TILIACEAE
The Tiliaceae or Linden family consists of about 50 genera of trees, shrubs or rarely herbs distributed widely throughout the world. The leaves are usually alternate and simple. Flowers are regular and usually bisexual and mostly in cymes in leaf axils or in cymose panicles. Peduncle united for about half its length to a large ligulate bract. Sepals and petals usually 5 but sometimes fewer, or flowers may be without petals altogether. Stamens are many and fruit a capsule or drupe. Tilia is the main medicinal genus.
Tilia spp. [Tilia x europaea, T. platyphyllos and T. cordata]
Lime, linden
Description
Tilia x europaea, the common or European lime, is a large deciduous tree to 40 x 5 m with an erect, branching trunk and reddish bark and buds. Leaves alternate, broadly ovate to 10 cm long, obliquely cordate or truncate, sharply serrate, dull green above with axillary tufts beneath. Flowers yellowish, fragrant, in drooping cymes of 5-10, staminodes present. Peduncle linked for about half its length to a large pale, ligulate bract. Fruit globose, 1-3 seeded, faintly 5-ribbed. T. platyphyllos, the largeleaved lime, is similar but with larger leaves, and branches and leaves pubescent. Cymes generally 3, or rarely 4-6 flowered. T. cordata, the small-leaved lime, grows to about 30 m and has nearly orbicular leaves, broader than long, finely serrate. Cymes 5-7 flowered, staminodes lacking. Flowers in midsummer.
Family Tiliaceae
Habitat and cultivation
These 3 species are native to Europe up to latitude 65°N. Planted in cooler climates elsewhere. Grown from seed, cuttings, layers or grafting, in cool, deep soils in open, sunny places. Frost resistant but drought tender.
Parts used
The flowers with their bracts harvested in early summer when the flowers are fully open.1
Active constituents
1) Volatile oil (up to 0.1%) including limonene, p-cymene, careen, germacrene-D, anethole and farnesol2,3
2) Flavonoids (about 1%) including derivatives of quercetin—quercitrin, rutin and hyperoside—and kaempferol—tiliroside and astragalin4,5
3) Phenolic acids including ferulic, chlorogenic, p-coumaric, caffeic and derivatives of cinnamic acid6
4) Mucilage (3-10%)7
5) Tannins (around 2%) of condensed type
It also contains saponins including scopoletin.8
Nutritional constituents
Minerals: Calcium, potassium, selenium, zinc and chromium9,10
Actions
1) Diaphoretic
2) Hypotensive
3) Sedative
4) Spasmolytic
5) Diuretic
6) Mild astringent
Scientific information
An official medicine in many countries, Tilia spp. have been valued as medicines in folklore.1 The flowers are approved by German Commission E for the treatment of colds and cold-related coughs. Very little current research of any sort has been conducted into the herb in spite of its widespread uses in many parts of the world.
A number of the active constituents have been examined in isolation and some research was undertaken in the past.
In vitro—Constituents including the flavonoids and scopoletin are hepatoprotective, anti-oxidant, inhibitory to the growth of some cancer cells11,12 and may, along with the herb itself, have immunomodulatory activity—stimulating T-cell proliferation. To date this has only be shown in animal models.13
The flavonoids from Tilia interact with benzodiazepine receptors in brain tissue of animals—this may indicate part of the mechanism for its relaxing effect.14
Human lymphocytes themselves have benzodiazepine receptors that influence immune function again this may explain the reputation that Tilia has in benefiting fevers, colds and influenza.15
Other studies report that the herb does not appear to have a strong anti-oxidant activity (its phenolic content is moderate).16 As an infusion it showed no mutagenic activity, acting instead as a desmutagen.17
In vivo—An epidemiological study on the drinking of herbal teas, including lime flower, found the practice was associated with a reduced incidence of breast cancer.18
Weiss quotes a study in which lime flower tea was used to treat children with influenza and this, with bed rest, was superior to antibiotic treatment.
Medicinal uses
Cardiovascular system
The actions of Tilia, including diuresis, give it an important place in the treatment of circulatory problems but added to this is the traditional reputation the species has in the prophylactic treatment of arteriosclerosis:
- hypertension
- varicose veins
- phlebitis
Respiratory tract
It may be used in the treatment of:
- fevers
- influenza
- common cold
- upper respiratory catarrh
- irritable coughs
Nervous system
As a relaxant it is used to help in the treatment of any condition of nervous tension.
- migraine
- restlessness
- insomnia
- hysteria
- headaches
Externally
Tilia may be used topically to treat skin conditions.
Pharmacy
| Three times daily | |
| Infusion of dried herb | – 2–4 g |
| Tincture 1:5 (25%) | – 4–10 ml |
| Fluid Extract (25%) | – 2–4 ml |
For diaphoresis a hot infusion is the most effective dosage form.
Precautions and/or safety
The herb has no known toxicity19 but Tilia pollen has been reported as a significant inhaled allergen20 and there are cases of contact dermatitis and respiratory allergy to the flowers.21–23
Lime flower tea reduced iron absorption from a simple meal by 52%, and may be best drunk between meals.24
Historical uses
Apoplexy; epilepsy; vertigo; indigestion; nervous vomiting; palpitations. As a bath for treatment of hysteria. Externally for burns and sores.