OLEACEAE

A dicot family of about 29 genera of trees or shrubs, growing in temperate or tropical regions in both hemispheres. The olive is the best known and many other members of the family are grown in parks and gardens as ornamentals.

Chionanthus virginicus

Fringe tree

images

Family Oleaceae

Description

A deciduous shrub or small tree growing from 2–7 m tall. Leaves, opposite, entire, oval, over 20 cm long, glabrous or downy, glossy green, turning yellow in autumn. Buds on previous year's growth develop into long stems with numerous delicate, fringe-like white flowers in 10–20 cm long panicles. (Chionanthus means “snow flower”.) Fruits blue-black oval elongated fleshy drupes with 1–3 seeds. Flowers from late spring to mid-summer.

Odour—none; taste—very bitter.

Habitat and cultivation

Native to North America from Pennsylvania to Florida and west to Texas. Available from garden centres and cultivated in all temperate regions. Propagated by seed or cuttings and grown in moist, sandy, loam soils in sunny situations.

Parts used

The root bark collected in autumn.

Active constituents

1) Lignans including phillyrin, pinoresinol and their glucosides1

2) Secoiridoids including oleuropein, ligustroside and angustifolioside B1

3) Saponins including chionanthin

The bark constituents are very poorly characterised.

Actions

1) Cholagogue

2) Laxative

3) Anti-emetic

4) Hepatic stimulant

Scientific informaion

The herb was an official medicine in the USA however there is very little scientific research available on any aspect of it. Its use is therefore reliant on tradition where it was considered of great value in treating liver-related diseases predominantly but also feverish conditions.

In vitro—The lignans have good anti-oxidant properties.2

Medicinal uses

Gastro-intestinal tract

Used for:-

Pharmacy

Three times daily  
Decoction of dried herb –   2–4 g
Fluid Extract (25%) –   1–3 ml
Tincture 1:5 (45%) –   2–3 ml

Historical uses

Fevers (typhoid, intermittent and bilious); dyspepsia including that of infants, gastritis due to alcohol, pancreatic disease; scrofula; syphilis; as a diuretic, nephritis; as a tonic, cachexia; to aid recovery from exhaustive illness. Externally for wounds, ulcers and inflammations.

Olea europaea

images

Family Oleaceae

Olive

Description

A long-lived evergreen tree growing to 10 m with a greyish deeply grooved trunk. Leaves elliptic-lanceolate over 7 cm long, leathery, green above, silvery beneath growing in opposite pairs. Flowers small, greenish-white in panicles, corolla tube short with 4 lobes. Fruit an oblong drupe, to 4 cm long, fleshy, green at first becoming glossy black when ripe. Many cultivars are available for oil.

Habitat and cultivation

Olives are native to the Mediterranean area where they have been cultivated for centuries as a source of oil. They are also cultivated worldwide in areas with a similar Mediterranean-type climate. Trees may be propagated by softwood cuttings or from suckers taken with a heel from around the tree trunk. They may also be grown from seed but seedling-grown trees are usually grafted later. They need a deep fertile well-drained soil to thrive. Drought resistant, frost tender.

Parts used

Leaves gathered throughout the year. Historically it has been the fruit and its oil that was valued in medicine. Both are still recognised in modern medicine for their contribution to a healthy diet although the oil is no longer used directly as a medicine. The fruit gathered green or ripe for pickling and ripe to be pressed for oil.

Active constituents

1) Phenolics3 including mainly:-

a) secoiridoids4,5 predominantly oleuropein (6–9%),6 also derivatives of elenolic acid and hydroxytyrosol—actual levels of these vary particularly with the age of leaf (green leaves are richer in oleuropein)7 but also to some extent with variety of olive,8 method of processing and time of harvesting8

b) flavonoids mainly derived from luteolin, also rutin and apigenin derivatives6,9–11

c) phenylpropanoids including verbascoside,9 caffeic,6 p-coumaric and ferulic acids12

2) Triterpenes of oleanane type including oleanolic and betulinic acids13

3) Volatiles including aldehydes, sesquiterpenes and monoterpenes14,15

Also contains a xylitol (0.5–1%)16 and β-sitosterol.17 Apart from the unsaturated fatty acids, the oil also contains phenolics similar to those found in the leaf18 and melatonin, the levels of the latter being higher in virgin than refined oil.19

Nutritional constituents

Vitamin: A and E

Actions

1) Hypotensive

2) Diuretic

3) Antiseptic

4) Spasmolytic

Scientific information

The oil has been an official preparation and is much better documented for medicinal use. The leaves have enjoyed a limited reputation in traditional medicine without having been registered officially. Recent studies on the leaf extract and/or its constituents have driven some of its current applications in proprietary natural medicines. However these uses are not supported by traditional medicine and are yet to be fully validated.

Anti-oxidant

In vitro—All the phenolic constituents are very good anti-oxidants,20,21,35 they appear to work synergistically,22 giving the whole leaf a very strong activity.23 This action protects cells from oxidative damage.24 Oleuropein, the main active constituent (also considered the bitter principle of the herb),12 slows down the aging of fibroblasts.25

As the processes of oxidation are believed to be behind the initiation of a number of diseases it is the anti-oxidant action that forms the basis of a good deal of the recent research into Olea.12 It is likely that this action, found in the oil and fruit also, is at least in part responsible for its epidemiological link of reduced risk of heart disease in the Mediterranean countries where they are routinely consumed.

Antimicrobial

The leaf has antiviral activity against HIV-126 as well as providing cells with protection from infection by the virus. The secoiridoids contribute to this activity by blocking viral attachment to host cells.27,28

Aqueous leaf extracts have broad spectrum antibacterial activity29,30 including against Staphylococcus aureus31 and dermatophytes including Candida albicans.29 Hydroxytyrosol, oleuropein, elenoate and the aldehydes all have a wide range of antimicrobial activity.14,32–35

Other

In vitro—The leaf inhibits the growth of leukaemia cells and encourages them to differentiate.36 It inhibits platelet aggregation and may be anti-inflammatory.37 The phenolic fraction is also anti-inflammatory.20

Some of the phenylpropanoid acids are well absorbed through the skin where they can prevent oxidative damage due to ultra-violet irradiation.38 In vivo—One clinical trial undertaken in 1996 showed the leaves were hypotensive39 an action for which they have been used traditionally.40 This may be due in part to the spasmolytic effect on blood vessels which has been demonstrated in animals only so far. Leaves have also been used in some traditions to treat diabetes.40

There are no in vivo studies reported into the effectiveness of the leaf in preventing or treating microbial infections, the claims for this action appears to be by extrapolation from in vitro research and/or anecdotal reports. The in vivo absorption of some phenols, particularly oleuropein, is still to be established, and it has been suggested that the large size and particular configuration of this molecule may mean that this is poor37 (see Pharmacokinetics).

Medicinal uses

Cardiovascular system

The vasodilatory effect of the leaves would explain its traditional use in fevers and for aiding:

Weiss has described the herb as being suitable for “labile and medium-severe hypertension”.

Gastro-intestinal tract

The combination of the bitterness of oleuropein, which should encourage digestive secretions, and the established in vitro research of its antimicrobial activity may indicate a use for the leaf extract in treating infections in this tract.

Endocrine

Based on tradition the leaves may be useful for:

Externally

The antimicrobial activity indicates a wash of leaf extracts may be used for:

Pharmacy

There are no official guidelines for dosage of Olea folia.

Three times daily suggested dosage41

Infusion of dried leaves   –   5–15 g

However there is this precaution from Weiss—the leaves may cause gastric irritation and should be taken after food.

Oil as a laxative single dose 15–60 ml.

Pharmacokinetics

Some preliminary studies failed to detect either oleuropein or its metabolites in plasma after the consumption of leaf extracts,42 however hydrotyrosol and tyrosol have been detected as glucuronides in urine.43

Historical uses

Leaf—fevers including malaria. Oil used as a nutrient, demulcent and purgative. The oil was used “to retard the flow of gastric juice” in the treatment of peptic ulcers44 and to treat constipation and/or impacted stools. Externally—as an emollient to soften crusty lesions, to soothe burns.