14.2 Multidisciplinary Approaches for Herbal Drug Discovery and Development
14.3 Analytical Herbal Medicine
14.4 Herbal Practices and Quality Standards
14.5 Herbal Translational Research
Plant based herbal medicines are getting consideration all over the world. The importance of herbal medicine and medicinal plants is realized globally as a source for drug discovery and development. Post genomic era offers the great opportunity to screen lot of bioactive components from the herbal medicinal plants with its various advancing technologies. Environmental changes occurring globally by the various activities of human beings due to which biodiversity of important medicinal plants are endangered and their decline from natural habitat is gaining significance for improvement, identification, analysis and conservation in the wake of sustainable development. The process of herbal drug manufacturing, standardization prescribes standards that impart safety, efficacy and consistency of herbal medicines. Hence, regulatory submission requirements for scientific data on quality, safety, and efficacy are indispensable to evaluate and permit to market an herbal drug on similar lines as synthetic, chemical moieties. In addition, global harmonization of herbal medicines combined with modern ‘omic’ technologies can facilitate enhanced support of public health and treatment of disease.
Plant derived substances which are not having any industrial process and used to treat illness are called herbal medicines. Herbal medicines are considered one of the main forms of complimentary and alternative therapy to modern medicine. There are more than 11,000 species of herbal medicinal plants in use, out of which about 500 species are commonly used in Asian and other countries. Large number of people relies on traditional medicines to meet healthcare needs. Although modern medicine exists, but traditional medicine being popular for its history and culture is getting attention all over the world.
Herbal medicines are available commercially in developed countries Germany, USA, UK and Australia. In Germany, herbal products are sold as ‘phytomedicines,’ and are subjected to the same criteria for efficacy, safety and quality as are other drug products. In USA, by contrast, most herbal products in the market are sold as dietary supplements, and the same does not require pre-approval of products. Herbal drugs, annual sales have gone up considerably in the recent times in Germany and in the USA. Use of herbal drugs increased 25% annually. In international market, the total European market for homeopathic medicines was £590 m in 1991, in recent times sale of herbal medicine is gone up to £1.45bn. Over 60% of the population in Germany, and 80-90% of the population in China uses herbs regularly (Li, 2002). In Europe, North America and Asia, herbal medicines are popular and always there is a demand (8-15% annually) for efficient herbal medicines (Grünwald and Büttel, 1996).
In recent years, the importance of herbal medicinal plants is realized globally as a source for drug discovery and development. In addition to low cost along with no side effects creates them ideal targets for newer drugs. Recent advances in ‘omic’ technologies, hyphenated technologies, biotechnology, nanotechnology, etc. as applied to clinical cases, evaluation of phytochemical constituents and their effective formulation have enriched herbal medicine. Validating the traditional herbal medicine has set forth a new theory of reverse pharmacology. In this chapter we have focused on multidisciplinary approaches of herbal drug discovery and development in the perspective of post-genomic era.
Ethnobotany, in general defined as the “science of people’s interaction with plants” deals with therapeutic applications of plants (Turner, 1996). The objective of ethnobotany is to develop new chemical moieties which illuminate pharmacological activities. For example, Kava, a social beverage, is one of the examples of ethnobotanical lead with new pharmacological knowledge. Today the goal of ethnobotany is to understand relationship between human population and plants associated ecosystems. Rich biodiversity regions, called hotspots, are the focal point of ethnobotanical guided research to find on medicinal active plants. Most of the traditional medicines are coming from the wild for domestic supply, while harvesting the medicinal plants care was not taken for the habitat, thus leading to deterioration of its density The 41st World Health Assembly (1988) resolution WHA41.19 along with Chiang Mai Declaration endorsed the call for international cooperation and coordination to protect and conserve medicinal plants (Guidelines on the Conservation of Medicinal Plants, 1993). Ethnobotany is a valuable tool in exploring the plant genetic resources for utilization in industries as well (Ogunkunle and Ladejobi, 2011).
Biodiversity is universality oflife forms living in various ecosystems. Biodiversity of important medicinal plants are endangered due to the environmental changes occurred globally from the various activities of human beings, i.e., land degradation, shortage of freshwater. This reduction in the biodiversity may have fewer discoveries of natural chemical substances, thus leading to reduction in vital medical and biological applications, which will have high impact in medical discoveries in future. Many ethno-medicinal plants found to grow in northeast India, examples are Swertia angustifolia Buch. (Gentianaceae), used against fever and malaria; Stemona tuberosa Lour. (Stemonaceae), used for the treatment of asthma and tuberculosis and Dillenia indica L. (Dilleniaceae), used against diarrhea and dysentery (Yacoub et al., 2014). Currently with the advancing technology one can use smaller quantity of plant material for example cell and tissue culture and these can be subjected to various stresses like chemicals or hot or cold climates to synthesize phytochemicals.
Phytochemicals are secondary metabolites produced as by products from the primary metabolism. Secondary metabolites are alkaloids, phenolics, glucosinolates, amino acids, terpenoids, oils and waxes. Research findings showed that these compounds can be used for medical purposes. The phytochemical constituents present in the plant are bioactive molecules which have been shown to treat for various physiological conditions of people. Screening of phytochemicals serves to identify various compounds which can be used for treating various diseases (Ganesh and Vennila, 2011).
The herbal traditional medicine practices vary between regions to region. The traditional medicine has strong indigenous culture and supporting evidence. WHO also agrees with herbal traditional medicine and its practitioners playing an important role in treating the disease and improving the quality of life (Abbot, 2014). Traditional medicinal knowledge (TK) is generally defined as “consisting of the medicinal and remedial properties of plants in indigenous culture,” including genetic resources. TK is often “defined by its general characteristics: creation through a long period of time which has been passed down from generation to generation; new knowledge is integrated to the existing, as knowledge is improved; improvement and creation of knowledge is a group effort; and ownership of indigenous knowledge varies between indigenous peoples.” Having access to use herbal medicine is a human right but it has a difference when it comes in terms of property rights for indigenous community. For example, vinblastine and vincristine from the Madagascar rosy periwinkle (Catharanthus roseus); the drugs have earned the firm around $100 million per year, either the government or shamans of Madagascar have not received any monetary benefit for their contribution. Commodification is a breach of human rights. IPR is not suited for protection of indigenous herbal drugs, since IPR recognize only individual contribution not a community (Arihan and Ozkan, 2007).
The preservation of traditional knowledge of herbal medicine practice from the practitioners should be globally recognized and the knowledge source should be easily identifiable (Batugal et al., 2004). Globally TK has gained special significance and demand for herbal medicines. In such trend there are issues regarding patenting and sharing benefits of traditional medicine. For example patent involved in the Jeevani case shows the partnership between TK and herbal and pharmaceutical industries. Knowledge focus in establishing an equitable IP agreement needs shift from patenting alone to benefit sharing with or without patents. In addition to community-based initiatives to protect local TK with respect to indigenous medicine, two important database initiatives, designed against patenting of indigenous medical products and applications of plants were established. One in India operates internationally for the defense of national TK, and the other, established by the Science and Human Rights Program of the American Association for the Advancement of Science (AAAS), operates internationally for the defense of TK globally (Chatterjee, 2002).
Ethnopharmacology deals with the study of indigenous medical systems, which connects the region where treating the disease is done and its importance in medical practices and continue to provide new drugs and lead molecules for the pharmaceutical industry. The recent introduction of artemisinin as an effective antimalarial is a good example of this as the source of this compound, Artemisia annua, was used to treat fevers and malaria-like symptoms in traditional Chinese medicine. Currently modern medicines used for treating major disease are developed from medicinal plants, for example, reserpine, withanolide and curcumin, etc. Herbal medicines are offering vast range of structural diversity for pharmacological treatment of various diseases. Herbal medicines are having synergic effects that deactivate the side effects produced by modern medicines (Mukherjee et al., 2014). Secondary metabolites such as alkaloids, diterpenes, flavones, phenolics, and triterpenes have been isolated and some of these have been shown corresponding biological activities like antibacterial and antiparasitic (Koay et al., 2013) and reported to be anti-pyretic, antidiabetic, anti-inflammatory, anti-malarial and health maintaining properties (e.g., Tinospora crispa). The hydroethanolic extracts obtained from Funtumia elastica, Raphyostylis beninensis, Butyrospermum paradoxum, Serataria caudula, Parkia biglobosa and Curculigo pilosa plant species showed significant antimicrobial activities and are used to treat skin diseases in Southwest Nigeria (Adebayo-Tayo et al., 2010).
Indian medicinal systems of treating the disease are about several thousand years old. Indians believes in traditional medical care and treatment, which is based on the concepts and practices of three ancient codified Indian Systems of Medicine (ISMs): Ayurveda, Unani and Siddha. Indian traditional medicine is the dictionary of herbal formulations. These traditional herbal medicines are capable of treating potential chronic diseases. For example in Indian Ayurvedic monographs depicted that reserpine (Rauwolfia serpentina) was used for treatment of high blood pressure (Vickers and Zollman, 1999). India has traditional knowledge for anti-malarial activities of various medicinal plants from the times of Charaka and Susruta (Gupta et al., 2015). In India traditional practice of treating disease is well practiced by Vaidyas and Hakims. Presently, there is slow deterioration of traditional knowledge of herbal plants in many countries.
India has enormous facilities to support herbal drug research which includes the Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Central Institute of Medicinal and Aromatic Plants (CMAP), National Botanical Research Institute (NBRI), Regional Research Laboratories (RRL), and National Chemical Laboratory (NCL) are playing pivotal role (Sen and Chakraborty, 2015). Herbal drug information, standardization of drug, quality control, and strict monitoring are the few complexities involved in the promotion of traditional Indian herbal products. In recent years several regulatory guidelines are released to overcome such problems. Quality control is required to establish the effectiveness and safety of herbal products. In order to provide improved health care facilities to mankind around the world, scientific integration of Indian traditional herbal medicine along with the international system of herbal medicine into evidence-based clinical management of diseases is essential.
Globally traditional herbal medicines are getting significant attention in relation to health. Traditional Chinese medicines have been a major player in treating chronic respiratory syndrome. In African countries 80% of population uses traditional herbal medicines. In Kenya most of people choose combination of herbal and modern medicine, especially for treatments of HIV/AIDS, hypertension, infertility, cancer and diabetes (Nagata et al., 2011). Sri Lanka has well reserve of herbal plants compared to any other country in Asia.
The herbal medicines have long term healing effects in the body. Genes or genetic material are modified when the herbal medicines are used. Among the existing herbal medicines one third of medicines are having the property to alter genes. Research showed that 36% of these medicines interact with the enzymes responsible for altering histone which is present in the human chromosome. These changes in the enzymes promote condensation of chromatin. Almost most of the herbal medicines are found to alter the histones. Moreover, these medicines make changes in the miRNA of cells and modify genetic epigenome. The curative effect of herbal medicine differs from the chemical medicine. Each herbal plant have tens of minimum of active components each will have effect on the body. The combination of all bioactive components will effect metabolism of the human body by interacting with the immune system, organ functions, different tissue systems and nerve cells (Hsieh et al., 2011, 2013).
Looking for genetic and biochemical properties of biological material which has commercial value is called Bioprospecting (Reid et al., 1993). Mainly there are two types of search or developing new drugs from herbal plants, one is from the lead component from existing traditional use, and another one is random screening for highly diversified chemical molecule from the medicinal plants. Assays are done to detect the biological activity after random screening. Diverse collection of natural products from genetic sources is the key for success in the development. For example, notable drug cyclosporine A from a fungus (Tolypocladium inflatum), rapamycin from a microbe (Streptomyces hygroscopicus) and anti-cancer agent paclitaxel are identified as a result of large-scale screening of plant extracts (Frisvold and Day-Rubenstein, 2008). India’s estimated biodiversity is 8% ofthe world with 3500 species of plants of medicinal value and 500 species being used in Ayurveda. Indian Government has constituted National Biodiversity Authority (NBA) to oversee utilization of plants of medicinal value for sustainability and equity (Singh, 2006).
Genetic engineering tools are important in genetic advancements and genetic transformation. Plant genetic engineering technologies combined with the culture of hairy root and crown gall paves a way for research and development to produce active pharmaceutical ingredients (Huangi, 2012). New transformation techniques allow silencing specific genes or stacks in the same region of chromosome. Due to the advances in DNA technology, obtaining genetic background of chemically important molecules aid to identify whether genes are able to produce bioactive molecules in plants (Huangi, 2012).
According to general guidelines for methodologies on research and evaluation of traditional medicines by WHO, first step is ensuring quality, safety, and efficacy of traditional medicines and correct identification and this can be done successfully by molecular markers. Molecular markers are genetic markers to identify plants at the gene level and develop new standards in standardizing herbal quality control. Molecular markers are highly polymorphic nature, and reproducibility makes data transfer facile between laboratories, for example, RFLP, SNP and AFLP (Srivastava and Mishra, 2009).
A method called combinatorial biosynthesis in which genes from different organisms are put together for synthesis of a novel plant product of pharmaceutical value. This method can be used for synthesis of new drugs as well as for enhancement of efficacy of existing drugs. Present development of modern experimentation envisaged on herbal drugs helps to fight against various diseases (Biotechnology Forum, 2013).
In plants increased production of important metabolites is accomplished through genetic engineering. Metabolic engineering improves the metabolite composition at the cellular levels thereby eliminating the undesired effects and enhances the production of existing secondary metabolites in plants (Ramesh Kumar, 2016). Recent advances in metabolic engineering have allowed increase in the concentration of lead components and identifying non characterized pathways. For example, metabolic engineering was used to produce paclitaxel under in vitro conditions (Engel et al., 2008).
Two approaches for conserving plant genetic resources are (in situ) farming and gene bank (ex situ). Over the period of time there is a genetic change that has occurred based on locations. By quantifying genetic change between these locations allows the genetic resource personnel to validate the gene bank protocols and recollect with appropriate intervals. This will help to address in case of species that can prevent further decline in vulnerable in situ populations. For example Trifolium pratense is used in traditional medicine of India as deobstruent, antispasmodic, expectorant, sedative, anti-inflammatory and antidermatosis agent (Stephanie et al., 2014).
The outcome from synthetic compounds didn’t fulfill the expectation from high throughput screening (HTS) platforms of pharmaceutical industry. This situation lead to discovery of plant based drug in herbal medicines. The Drugs from Nature Targeting Inflammation (DNTI) program aimed at identifying and characterizing natural products with anti-inflammatory activity by the combined and synergistic use of computational techniques, ethnopharmacological knowledge, phytochemical analysis and isolation, organic synthesis, plant biotechnology, and a broad range of in vitro, cell-based, and in vivo bioactivity models (Fakhrudin et al., 2014). Mostly plant-derived substances are identified based on forward pharmacology approach. Reverse pharmacology uses in vitro screening of large number of plant-derived compounds against pre-characterized diseaserelevant protein targets to identify the bioactive molecules (Zheng et al., 2013).
Biotechnology tools are equally important in multiplication, plant cell culture-selective metabolite production, and tissue culture-vegetative propagation (Siahsar et al., 2011). Plants tissue culture helps vegetative propagation in a short duration, which has the capacity to reproduce millions of genetically and physiologically identical medicinal plants. Another application of plant tissue culture is to isolate the drug from suspension culture, in which uniformity in production of the desired products and reduce considerable time and manpower with increase in production of the drug (Hussain et al., 2012). Various tissue culture studies were done exhaustively to enhance the production of chemicals in medicinal plants for, for example, Swertia chirayita, Cathranthus roseus, Panax ginseng, Stevia rebaudiana, Artemisia annua, Elettaria cardamomum, Allium chí- nense, Camellia sinensis (Pradhan et al., 2013; Pant and Thapa, 2012; Nongdam and Chongtham, 2011).
Bioreactor is designed for mass cultivation of plant shoots and plantlet cultures which can result in high number of plant secondary products/bioactive compounds compared to the whole plants. Bioreactor has several advantages, not only in giving nutrition in a controlled environment for the growth of mass cell culture, but also helps plant cells to carry out biochemical trans- formation which leads to synthesis of bioactive components. Bioreactors provide better control, constant regulation of plant cell growth, simple and trouble free harvest and uptake of nutrients, thus leading to high multiplication rate and high yield of bioactive compounds. It gives great hope to the pharmaceutical industry. Furthermore, bioreactor prevents deterioration of natural herbs and helps mass cultivation. This method can be used for most of the lifesaving drugs (Popovic and Portner, 2012).
Tools of biotechnology are increasingly applied to conserve plant genetic resources. Several in vitro techniques have been developed for storage of vegetative propagation and recalcitrant seed producing species, which includes: (i) slow growth procedures, (ii) cryopreservation (Kasagna and Karmuri, 2011). Cryopreservation helps to store germplasm at -196° C to ensure storage efficiently of plant cells for a longer time. Maintaining genetic integrity is one of essential criteria while preserving plant cells under cryopreservation. Flow cytometry technique helps to check genetic stability in in vitro regenerated plants as well as cryopreserved regenerated plants (e.g., Oncidium flexuosum Sims for its wound healing property) (Galdiano et al., 2013).
To study the structure and function of genomes, recombinant DNA technology, sequencing, and bioinformatics are applied and is known as genomics (Freyhult et al., 2008). Draft of human genome published in the year of 2003 lead post genomic period received more attention and progress on personalized health care with the advent of genomic profiling. In addition it made way to every single disease risk and the approach towards the healthcare management (Mendoza and Maria, 2010). Advances in high throughput sequencing technologies help us to analyze a complex chemical mixture which have more than one lead component and is termed as herbal genomics. It helps to understand the quality and identify of herbs at molecular level. Modification of chromatin structure without changing primary DNA sequences makes alteration of expression in genes called epigenetic regulation (Boonsanay et al., 2012). High advances in technology leads to integrating epigenomics, spatial organization and genomic evolution into the total cell profiles, the data can be useful if it is clearly interpreted by the researcher. Post genomic era offers the great opportunity to screen lot of bioactive components from the herbal medicinal plants with its various advancing technology especially with epigenomics and bioinformatics technologies (Falcone, 2014).
Next-Generation Sequencing (NGS) produces millions of short DNA sequence in short time with less cost. It includes template preparation, sequencing and imaging, and data analysis in which protocol distinguishes one technology from another and by the amount of the data produced from each platform. In the NGS techniques, DNA templates are randomly read along the entire genome in a massively parallel sequencing by splitting the entire genome into small pieces followed by adapter ligation to the fragmented DNA (Zhang et al., 2011). DNA barcoding is meant to identify small, standardized gene sequences in a rapid, accurate, and cost-effective manner in the plant materials. Chloroplast/ nuclear regions are used by researchers as universal barcodes for the authentication/adulteration of phyto-medicines. Plastome sequencing/ superbarcode is an enhanced progress in DNA barcoding through Next Generation Sequencing. It identifies the presence of various plant species in herbal mixtures. By using DNA barcoding technologies, integrity and authenticity of herbal medicines can easily be identified and it also protects the health of mankind from adulteration of herbal products. Barcode databases available for plants are as follows: GenBank - USA, BOLD - Canada, Medicinal Materials DNA Barcode database - China (Balachandran et al., 2015).
Plant tissue used to generate cDNAs from mRNA populations and sequenced to generate Expressed Sequence Tags (ESTs) represent the transcriptome. The transcriptome sequences are annotated for putative function using a suite of bioinformatics approaches such as sequence searches of protein databases, motif/domain identification, biochemical pathway mapping, and sub cellular localization predictions. Transcript abundance data can also be used to provide in-depth expression profiles of individual genes on a per tissue/treatment basis. The deduced function, coupled with expression frequency, can facilitate identification of candidate genes pertinent to the pathway of interest as well as non-pathway targets (e.g., primary/intermediary metabolism) whose expression is consistent with synthesis of compounds.
DNA microarray is an orderly arranged sequence of genes on impermeable sheet like microchip and nylon. It allows a detailed analysis and investigation of gene expression. In herbal drug discovery it helps to identify the genes responsible for the lead components, identification of specific herbal components and its validation in pharmaceutical industry (Khan et al., 2009). Genetic variants involved in the gene expression in the toxicity profile and difference in effect between patients can be analyzed through Micro array technologies (Hanna, 2012).
Metabolomics is the complete quantitative and qualitative analysis of all metabolites present in a specific cell, tissue, or organism (Shyur and Yang, 2008). Metabolomics is one of the key approaches of systems biology that consists of studying biochemical networks having a set of metabolites, enzymes, reactions and their interactions (Tagore and Chowdhury, 2014). The challenge is the subsequent compound identification and handling the noise or false-positive peaks in a spectrum of complex metabolic profiles. Metabolomics is an important emerging technology in field of phytomedicine, drug development, and toxicology, combined with hyphenated analytical methods (e.g., gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR) spectroscopy) and data mining tools to generate comprehensive metabolic profiles of an organism. Advancement in metabolomics provides an opportunity to segregate and measure complex matrices of plant tissues which helps to assess any modifications of the metabolic pathways.
Some metabolomics studies have characterized plant metabolites of nutritional importance and significance (Hall et al., 2008) and shown intricate relationships association between the intake and metabolism of dietary phytochemicals with human health (Manach et al., 2009). Metabolome analysis with LC-MS is a unique method for profiling of pharmacologically bioactive secondary metabolites (e.g., carotenoids, flavonoids, saponins, alkamides, alkaloids, and glycosidic derivatives) (Matsuda et al., 2009; Moco et al., 2009; Hou et al., 2010). Metabolomics aid to recognize bio- markers for drug action.
Post genomic era advances helps in targeted genome modification, specific gene expression of tissue, cell and organelle and controlled expression pathways of multigenes (Wilson and Roberts, 2014). The experimental system and tools are readily available in omics era to approach multiple molecular gene targets. Evolution of metabolic engineering with high throughput methods for gene discovery and functional analysis is a new platform for testing heterologous pathways in plants. Providing the metabolome for medicinal plant to know and have a deeper understanding of the metabolic potential of plants gives an opportunity to the investigators to identify the sites of synthesis and accumulation of structurally diverse compounds. Determining the metabolome for a plant involves the profiling of the small molecules varying in size from 100 to 2,500 atomic mass units found throughout the plant in all the tissues and organs, and in response to various growth conditions. Single analytic method is not sufficient to study all the chemical diversity within a plant, but by using LC-TOF (liquid chromatography-time of flight mass spectrometry) method one can document the non-targeted (documenting the metabolites without any bias) profile of small molecules (metnetdb.org).
Bioinformatics act as an essential tool for the identification of genes and its pathways that correlate with important bioactive secondary metabolites in medicinal plants. The International Ethnobotany Database (ebDB), NAPALERT and USDA maintain a database for medicinal plants. The majority of genomics resources for plants have come from ESTs. Transcriptlevel information could be valuable to molecular biology-based research relative to medicinal plants. Bioinformatics approaches can be used to create coexpression networks from transcriptome data, providing possible leads to gene discovery in related plant species. In particular, the use of comparative genomics provides basis for exchange of information among the different species (Sharma and Sarkar, 2013).
Proteomics used to interpret and investigate physiological conditions, mutations, changes in response to external factors, and adaptation. Proteomics is an analytical tool, two-dimensional gels coupled with tandem mass spectrometry-based isobaric tags, allows the systematic quantitative and qualitative mapping of the whole proteome in case of any diseased condition (Hussain and Huygens, 2012). Protein alterations are a potential target to understand drug’s mechanism of action by using proteomics tools. Proteomics can also involve in the identification of post-translational protein modifications (Mann and Jensen, 2003; Zhang and Ge, 2011). To study the changes in the protein and protein interaction in vivo and in vitro before and after herbal medicine treatment proteomics is used to study the mechanism of action of remedies (Cho, 2007). Proteomics can also be used to understand the mechanism of action of herbal remedies for diseases including neurological diseases, cancer, and diabetes. For, for example, Podophyllum hexandrum in anticancer treatment (Bhattacharyya et al., 2012).
Systems biology includes all omics (genomics, epigenomics, proteomics, and metabolomics, lipidomics, etc.) that explains the interactions between biological system components and to understand the biological system behavior (Oberg et al., 2011). To answer how each component assembles and form a structure in the biological system and how its interaction produce complex system behaviors, and how changes in conditions may alter these behaviors systems biology has come out as one of the important area of research in drug discovery that leads to the interpretation of genome data at systems level and understand molecular basis of disease and mechanism of drug action. It is visible that cancer disease is more complex, due to combination of multiple molecular abnormalities, which supports a novel network perspective of complex diseases. Systems biology makes possible for translating preclinical discoveries into clinical benefits for, for example, Biomarkers (Ziu et al., 2013).
Recent technologies that are available to interpret different information on complex biological phenomena at systems level have increased. The development of high-throughput technologies, data analysis methods and omics technologies have made it possible to understand biological phenomena because of the huge information obtained. Along with it bioinformatics, data mining, machine learning, made possible to understand and predict interactions and patterns of biological systems. Very recently developed database of medicinal materials and chemical compounds in northeast Asian traditional medicine (TMMC), has tried to overcome the problems faced by prior databases, such as redundancy of herbs in a system, and contains medicinal materials from Korean, Chinese and Japanese pharmacopeias. Another database is the anticancer herbs database of systems pharmacology (Cancer HSP) is a specialized database on anticancer herbs. It has anticancer activities from 492 cancer cell lines, helps to define the molecular mechanisms of anticancer activities. Shortcomings of origin, synonyms of the medicinal plant and language are solved and the researchers have made many studies based on databases (Lee, 2015).
Nanotechnology in herbal medicine is playing a lead role in drug delivery. The reach of plant molecules at the affected parts in human body is poor due to low permeability, low solubility and low bioavailability, and these properties are masked by using them with encapsulated nanomaterials for safe herbal drug delivery. Nanotechnology helps to develop and commercialize macromolecules to deliver the bioactive molecule at intracellular level precisely. Herbal medicines incorporated into novel drug delivery system, such as nanoparticles, microemulsions, matrix systems, solid dispersions, liposomes, solid lipid nanoparticles are delivered carefully at the site of action without side effect and enhance the bioavailability (Sachan and Gupta, 2013). Nanotechnology is used to reduce the toxicity and side effects in pharmaceutical medicine. Herbal nanocarriers help to treat the dangerous diseases like cancer. The nanoparticles can enhance the therapeutic index and pharmacokinetics of herbal drugs, for example, Liposomes in cancer drug delivery. Nanoparticles introduce the gene and activate it accurately and manage with no side effect after its use (Pandey and Pandey, 2013).
Medicinal plants are widely used for treating illness and assumed to be safe, but these medicines are potentially toxic due to misidentification of the plants or incorrect preparation and administration by inadequately trained personnel (Nasri and Shirzad, 2013). Plants produce primary and secondary metabolites that have various toxic elements. Intake of such plants will give negative effects, thus, it is imperative to study the elemental contents of medicinal plants to highlight safety and efficacy of traditional herbal medicines and it is important to have herbal medicines with no side effects. In practice, herbal plants can be identified from a toxic/safety point of view. Herbal plants have pharmaceutical concentrations of poisonous constituents which should not be taken internally, for example, Arnica spp., Atropa belladonna, Aconitum spp. and Digitalis spp. Herbs with potential actions should be used only under appropriate conditions. There is a distinct group of herbs which has specific kind of toxicity, for example, hepatotoxicity of pyrrolizidine-alkaloid, Comfrey, Dryopteris, Viscum, and Corynanthe (Nasri and Shirzad, 2013). In Tanzania 25% of the corneal ulcer and in Nigeria and Malawi 26% of the childhood blindness were associated with the use of traditional eye medicine as per the studies conducted (Sushma et al., 2011).
Harmonized standards oftoxicity testing methods for herbal medicine toxicological characterization was done globally. Next generation sequencing and computer-based modeling and simulation tools are used to predict the potential toxicity of herbal medicine which may arise from herbs administered alone or concomitantly with other herbs and/or drugs. To ensure chemical uniformity and detect chemical adulterants in herbal products, hyphenated technologies are used (Ifeoma and Oluwakanyinsola, 2013). Hyphenated technology is the combination of separation technique along with spectroscopic detection technique. Using various hyphenated technologies which includes for example, GC-MS, LC-MS, LC-FTIR, LC-NMR, CE-MS, etc. helps to isolate from crude extracts or fraction from various natural sources and on-line detection of natural products, using LC as the separation tool. Hyphenated techniques are used for the qualitative and quantitative determination of compounds in natural product extracts. Since these techniques are coupled with the separation and detection techniques, it helps to solve complex structure of natural products. The physical connection of HPLC and MS or NMR has increased the capability of solving structural problems of complex natural products. Considering trace analysis is vital, LC-MS has been considered one of the potential tools (Patel et al., 2010).
The process of herbal drug manufacturing, standardization prescribes a set of standards that imparts safety, efficacy and consistency and it is meant for quality control (Kunle et al., 2012). Standardization includes all quality measures taken at the time of manufacturing process (Shinde et al., 2009). Quality control ensures safe, consistent and predictable performance and is dependent on before and after the harvesting processes. This covers Good Agricultural Practices (GAPs) and Good Manufacturing Practices (GMPs). The World Health Organization (WHO) has encouraged the development of national standards and guidelines to evaluate the quality of traditional drugs. It has also emphasized on the need to develop national pharmacopeia and monographs of medicinal plants as well as the protection of biodiversity (WHO, 2005; Shinde, et al., 2009).
The current development of herbal medicine is focused on the manufacture process, quality control standards, material basis and clinical research. Herbal medicine should be safe, consistent and predictable performance. Quality control should be followed during the manufacturing process, which is based on collection and extraction processes (Chege et al., 2015). Quality control is a foundation step for the manufacturing herbal product and which should suit for biological and clinical studies. A typical drug preparation includes mixture of many plants and having vast chemical component that function synergistically to get a therapeutic effect. A combination of analytical finger printing and quality control is useful to monitor consistency in each batch and to assure authenticity and quality through multi-component assay that has been developed and applied for several Chinese herbal medicine preparations, for example, Salvia miltiorrhiza (Guo et al., 2015).
Good Clinical Practice (GCP) provides assurance that a study’s results are credible and accurate. It includes conduct, performance, monitoring, auditing, recording, analysis and reporting and that the rights and confidentiality of the study subjects are protected. It is necessary to have a system management of safety evaluation, for toxicology research of herbal drugs based on standard of Good Laboratory Practices (GLP) (Gao et al., 2012). GLP inspections are to review the non-clinical safety, toxicological and pharmacological studies proposed in human applications for herbal marketing authorizations and various post-authorization applications submitted to any regulatory agencies (EMA, 2015). GLP ensures the quality and reliable data by complying qualified Study Director for each study, a quality assurance unit, adequate test system care facilities, characterized test samples, equipment that has been calibrated to perform its function and procedures for the activities. The GLP compliances need to have documentation of all laboratory activities. It should include the result of original observations and activities of a non-clinical laboratory study, since it is essential for reconstruction and evaluation of specified study. All the study related information should be archived properly to retrieve raw data, documents, protocols/plans, and specimens generated as a result of a non-clinical laboratory study.
Herbal medicines are alternatives to modern medicine for treating complex disease. To validate the effects of herbal medicine, recent technology is used. To transfer the knowledge from laboratory to clinical setup the barrier between clinical and basic medical sciences is overcome with Translational Research. For bronchial asthma, herbal formulation (UNIM-352) is used. Clinical and experimental studies were conducted to validate their observed effects. The results indicate that this poly-herbal agent could be used as an alternative/adjunct in the treatment of bronchial asthma (Gulati, 2015). Ethnopharmacology is contributing the evidence-based data. Traditional medicines are taken only when the availability of experimental data and clinical data are established. The standard studies are ensuring the safety and efficacy of medicine. Clinical studies should focus on effectiveness by including various populations in the usual healthcare setting (Leonti and Casu, 2013).
Ethnopharmacology not only applies forward-translational research but also back-translational research, starting with traditional treatment observations of patients undergoing trial and the findings into para-clinical trials and laboratory studies. This strategy, referred to as “reverse pharmacology”, has the advantage that it is more efficient and much faster than with traditional approach. Reverse pharmacology comprises three domains. The first one is the experiential phase that includes documentation of clinical observations/ formulation effect from traditional medicine or developed drug which has all the details of drug formulation. Second, is the exploratory study to evaluate target activity by para-clinical study using relevant in vitro and in vivo models. Third phase includes experimental studies, to identify and validate reverse pharmacological correlates of safety and efficacy of drug candidates. Finally, reverse pharmacology can improve efficiency with minimal toxicity (Surh, 2011). For example, the decoction of Argemone mexicana, used as an antimalarial traditional medicine in Mali used the method of reverse pharmacology.
Comparative effectiveness research (CER), a current trend in clinical medicine research supports the real world evidence based criteria. CER aims to provide evidence from the real life that helps clinicians and patients to select the treatment options which is best suited for individual preference and needs. It uses a combination of research technologies i.e., omics technologies. It is useful in identifying, connecting and interdependence of each component with various level of organization (Witt et al., 2015).
Herbal medicine consumption is 80% around the world, according to statistics given by WHO. There is a challenge in the safety and efficacy of herbal drug and there is no scientific evidence to support the issue. It is known that most of the population is consuming herbal drugs, thus it is the need of the hour to prove the efficacy of herbal drugs through clinical trials and is advised to use single and consistent batches of formulations (FDA, 2004). This issue can be solved by using modern technologies in clinical trials. Several clinical trials were performed, but there is a wide gap to comply international medicine policy. In general clinical trial should be carefully designed protocol and prove the safety and efficacy of the drug when it is used first in human. In herbal clinical trials inclusion criteria includes both modern diagnosis and traditional diagnosis, thus treatment is given by using traditional medicine and outcomes are analyzed by using modern and traditional systems (Leung, 2004; Jonas and Linde, 2002). Not having standard methods in preclinical trials and too many clinical trials on herbal products is poor quality of clinical trials. Regulatory authorities need to assess the purity of medicinal plant substances used and contraindication of the substances with other medicine (Jäger, 2015). In India DCGI released guidelines for safety and efficacy of herbal drugs in the year of 1993.
Herbal clinical trials have several challenges such as quality, finance and ethics. Quality and consistency ofthe traditional herbal products can be made possible through advanced scientific methodologies and carefully planned clinical trials. Safety and efficacy of clinical trials start with randomized clinical trials. Current herbal medicine clinical studies outcome show deficiency in the quality trial reports such as design, execution and analysis and the information of drug. Though traditional use does not ensure the safety and effectiveness of herbal medicines but it is useful guide for identification of new pharmacologically active substances in plants. A reverse pharmacology/toxicology or “bedside-to-bench” approach starting with a rigorous collection of clinical data in field surveys, as suggested by Graz (2013), may be a fruitful strategy to improve knowledge on the safety of traditionally used herbal medicines (Moreira et al., 2014).
China, Japan, and Germany have their national policy and laws on regulations of traditional herbal medicines (Parveen et al., 2015). To prove the efficacy of clinical trials, it is advised to use single and consistent batches of formulations (FDA, 2004). World Health Organization (WHO) released guidelines and regulatory requirements needed to support clinical trials of herbal products (WHO, 2005). In herbal clinical trials, inclusion criteria can be based either on modern medicine or herbal medicine diagnosis to understand the nature of the disease (Leung, 2004). Therefore, it becomes difficult to define inclusion and exclusion criteria and hence Jonas and Linde have devised a “double classification method” where subjects are primarily diagnosed using modern diagnostic criteria and then are classified according to the traditional system. Treatments are given according to traditional classification and outcomes are evaluated by criteria for both the systems (Jonas and Linde, 2002). In randomized clinical trials (RCT), blinding is a gold standard that eliminates bias and isolates placebo effects. Treatment allotment is not known by the investigator and the subject.
Consistency in high quality, effectiveness of treatment, safety and patient affordability are the major player in the drug development. The principles underlying in translational research is the standard bottom up bench to bed side. Clinical studies should be conducted in parallel. A well-defined methodology for standardized assessment of the quality, efficacy, and safety is must before starting of any basic project (Yang et al., 2014). For topical treatment of external genital and perianal warts Veregen (sinecatechins) is the first FDA approved herbal drug in the year of 2006 and the second is Fulyzaq (crofelemer) for symptomatic relief of noninfectious diarrhea in patients with HIV/AIDS on antiretroviral therapy in 2012. It shows that herbal drugs can be developed to comply the FDA standards of quality, safety, and efficacy (Lee, 2015).
Around the world various indigenous herbal medicines have evolved from diverse ethnic, cultural and geographical backgrounds. Ensuring safety and efficacy of these products is not well standardized and the regulatory requirements of these products, varying from country to country, present an important challenge. Consumer interest in the herbal products globally leads pharmaceutical industry to focus on herbal medicines for economical reason. Most of the countries are allowing legalized trade of herbal products. But complexities in quality, safety and efficacy data, differences in the status of ingredients and excipients are delaying growth of herbal drug industry (EMA, 2004). In Europe, for the marketing approval is based on Traditional medicinal use provisions accepted on the basis of continuous use for medical treatment at least 10 years with in Europe and safety and efficacy data from the literature or developed from own treatment.
In India, herbal drugs are regulated under the Drug and Cosmetic Act (D and C) 1940. Department of AYUSH (Ayurveda, Unani, Siddha medicine) is the regulatory authority in India. According to AYUSH norms it is mandatory for any herbal drug manufacturing company should get the license (Malik, 2013). The D and C Act extends the control over licensing, formulation composition, manufacture, labeling, packing, quality, and export under the category of ASU drugs and Patent. Schedule “T” meant for Good Manufacturing Practice (GMP) to be followed. The quality standards of the medicines are found in official pharmacopeias and formularies. Ayurvedic medicines are in increasing demand from India and (Chaudhary and Singh, 2011) several drugs from ISMs have undergone clinical trials to verify and prove their efficacy.
Ayurvedic products have been successfully evaluated in clinical trials for the treatment of bronchial asthma, rheumatoid arthritis, ischemic heart disease, and cancer, among other illnesses (Patwardhan et al., 2005; Gupta et al., 1998, 2000; Chopra et al., 2000; Kumar et al., 1999). To establish the effects of drug and to compare the potency of traditional medicines with allopathic medicines clinical trials are done in India. In Indian regulations, the major class of drugs includes Ayurveda, Siddha, or Unani (ASU) drugs. Classical ASU drugs, issue of license to manufacture are based on citation in authoritative books and published literature, unless the drug is meant for a new indication when proof of effectiveness is required. Safety and efficacy studies are not required for marketing approval, as per the Drugs and Cosmetics Act of 1940 (DCA). Patent or proprietary medicine makes use of ingredients from authoritative texts but with intellectual intervention and invention to manufacture products vary from the existing classical medicine. For this category issue of a license to manufacture requires proof of effectiveness, based on the pilot study protocol relevant to ASU drugs. In India, ASU drugs have been under the scrutiny of Department of AYUSH. In 2015 regulatory requirements for phytopharmaceuticals are under the purview of the Central Drugs Standards Control Organization (CDSCO).
Regulatory submission requirements for scientific data on quality, safety, and efficacy are essential to evaluate and permit marketing for an herbal drug on similar lines to synthetic, chemical moieties. In Schedule Y, the newly added Appendix I-B describes data to be submitted along with the application to conduct clinical trial or import or manufacture of a phytopharmaceutical drug in the country. The regulatory requirements for NDA for the phytopharmaceutical drug include standard requirements for a new drug-safety and pharmacological information, human studies, and confirmatory clinical trials. For phytopharmaceutical drug, there is a lot of stress on available information on the plant, formulation and route of administration, dosages, and therapeutic class for which it is indicated and the claims to be made for the phytopharmaceutical, and supportive information from published literature on safety and efficacy and human or clinical pharmacology information and data generated on manufacturing process and quality control.
The new regulation for phytopharmaceutical is in line with regulations in USA, China, and other countries involving scientific evaluation and data generation. In India, USA and China regulation is expected to promote innovations and development of new drugs from botanicals in a scientific way and would help in the acceptance of the use of herbal products by modern medical profession. A report of a global survey on national policy on traditional medicine and regulation of herbal medicines indicated that most of the countries including China, Japan, and Germany have their national policy and laws on regulations of traditional herbal medicines and efforts should be made for the integration of traditional medicine into national healthcare systems.
In Malaysia herbal products need to be registered with the Malaysian Registrar of Business. Herbal drugs are classified into Traditional products and Health supplements and labeling is mandatory (Shak and Mohamed, 2011).
Herbal products are categorized under complementary medicine by Therapeutic Goods Administration (TGA) regulatory agency of Australia. Herbal medicine has to be registered before marketing in case of high risk whereas the low risk medicines are listed under complementary medicine and should support for the claim (TGA, 2014).
Any herbal drug should be marketed under Approved New Drug Application as per the regulatory norms of USFDA (NDA), Dietary Supplement Health and Education Act of 1994, FDA, manufacturer has to ensure safety of the herbal product, though pre market approval is not necessary and labeling as per the FDA compliance and the drugs should be manufactured as per the present GMP for dietary supplements (FDA 2004, 2014). FDA Botanical Drug Development Guidance recommends that IND should have data to support for the drug is safe if it is given to the humans. In addition pharmacology/toxicology studies, to prove/ensure safety and efficacy of the drug by product documentation which has studies on animals and the raw materials used, i.e., evidence to support quality control and evidence to ensure therapeutic consistency are needed.
In Canada from 2004, before initiation of any activity related to the herbal drugs, manufacture or marketer has to register with Health Canada. The process involves registration of the manufacturing site(s) along with the products. Complete data on product composition, standardization, stability, microbial and chemical contaminant testing methods and tolerance limits, safety and efficacy along with ingredient characterization, quantification by assay and comply with GMP norms (Health Canada, 2013).
The European Medicine Agency (EMA) has two types of registration of herbal medicinal products: (1) A full marketing authorization by submission of a dossier includes the information on quality, safety and efficacy of the medicinal products including the physicochemical, biological or microbial tests and pharmacological, toxicological and clinical trials data; under directive 2001/83/EC. (2) Traditional herbal medicine which has, long traditional use and not having scientific evidence can submit a simplified procedure under directive 2004/24/EC. The product should comply with the quality standards in European Pharmacopoeia. The evidence should support that the medicine was used for at least 30 years out of which 15 years the medicine should be practiced in the Europe.
Herbal medicines in China are normally considered as medicinal products with special requirements for marketing, for example a quality dossier, safety and efficacy evaluation, and special labeling. New drugs have to be examined and approved according to the Drug Administration Law. After approval, a New Drug certificate is granted an approval number. The factory is then permitted to put the product on the market. This procedure reflects the respect in which traditional experiences are held, while modern scientific and technical knowledge is used in appraising the therapeutic effects and the quality of the modified traditional medicines, and contributes administratively to the exploitation of traditional Chinese medicine (Wang, 1991).
Medicinal plants are serving as rich resources of traditional medicine and curing the diseases for long. Currently allopathic medicines have become very costly thus leading to the development of herbal drugs and being considered equal to modern therapy in developing countries. Therefore, it is a crucial time to develop plant-based drugs involving ethanobotanist, researchers from diverse fields and pharmaceutical companies. Post genomic era which offers latest technologies could help us to derive the chemicals/plant based medicine with the traditional knowledge of our very ancient system of medicinal practices as well the plant based medicinal script which was written in ancient times. In terms of development of herbal drug, when compared to modern medicine, it has high success rate and enhance the drug development in near future in order to have a safe drug to boost national health.
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