Yew

Yew
This genus includes 5-10 species of evergreen coniferous trees and shrubs, occuring throughout northern temperate zones and into SE Asia and C America. Male and female flowers are usually borne on separate plants. Yew trees are widely planted as specimen trees, hedges, and topiary, in spite of the fact that all parts, except the aril, are extremely poisonous. Eating the leaves of yew is a common cause of death among livestock, which succumb so quickly that the foliage of the plant is often still found in the mouth of the animal. The common yew (Taxus baccata) is renowned for its longevity. Reliable records date some British trees to at least 1500 years old, and the Fortingall yew in Perthshire, Scotland is estimated to be over 8000 years old, though the trunk is hollow, so precise dating is not possible. Yew trees were sacred to the Druids, who built their temples nearby - an association continued by the Christian practice of planting yew trees around churches. In the 1960's, the Pacific yew (Taxus brevifolia) was found to contain paclitaxel or taxol, which was first isolated in 1971 and , after clinical trials that began in 1983, was hailed as one of the most promising drugs for treating ovarian and other cancers.. In the form of tamoxifen, the drug reduces rates of death from breast cancer by 30 percent. At the outset, and enormous number of trees were needed to supply Pacific yew bark for the drug; in order to provide sufficient taxol to treat a cancer patient, the bark of six trees is required. The resulting increase in exploitation of T.brevifolia in the USA led to the Pacific Yew Act (1992), which provides for the management of trees on federal lands, covering both harvesting and conservation. Subsequent research, reported in 1996, found the taxol exists in a fungus, Pestalotiopsis, the grows symbiotically in other species of yew, and in other tree species, enabling taxol to be produced more cheaply and easily, and without further endangering the Pacific Yew. In particular the Himalayan yew (T. wallichiana, yields far higher quantities of taxol. Taxus baccata also contains taxol; it has been utilized in the UK through a program to collect prunings from properties where there are significant plantings of yew hedges. The bark and twigs of T. canadensis (Canadian yew) have been used by several native N American tribes in a tea to treat influenza.

This forty- to fifty-foot-tall tree with its wide spreading branches was considered sacred by the Druids, who built their temples nearby. Later, early Christians followed suit, and these trees are still associated with places of worship. The yew's extremely hard, water-resistant wood was once in great demand for making longbows. Yew also has important medicinal uses, as it contains an anticancer substance called taxol, which has been refined to produce a drug used for breast cancer.

Domed, spreading evergreen tree with scaly, purple-brown bark and dark green, linear leaves, to 3cm (1¼in) long, arranged in two ranks on either side of the twigs. Pale yellow flowers appear in spring; females followed by single green seeds, surrounded by a fleshy red aril, 1cm (½in) across.

Common Name:

Yew

Other Names:

Common Yew, Common Yew, English Yew, European Yew

Botanical Name:

Taxus baccata

Genus:

Taxus

Family:

Taxaceae

Native Location:

Europe to N Africa and Iran

Cultivation:

Well-drained soil in sun or shade. Trim hedges and topiary in summer and early autumn. Withstands hard remedial pruning.

Propagation:

By seed sown in autumn; by semi-ripe cuttings in late summer or early autumn. Seeds may take two years or more to germinate.

Harvest:

Leaves are picked in early autumn or in spring, and bark is collected from autumn to spring, for commercial extraction of taxol.

Varieties:

Dovastonii Aurea
Is a small female tree with spreading branches, pendant branchlets, yellow shoots, and yellow-margined leaves.
Height: 3-5m (10-15ft)
Width: 2m (6ft)

Fastigiata
Syn. Hibernica
(Irish Yew)
Is a female tree with a narrow, upright habit and leaves arranged radially.
Height: 10m (30ft)
Width: 6m (20ft)

Repandens
Is a female shrub with a prostrate, mound forming habit.
Height: 60cm (24in)
Width: 5m (15ft)

Height:

10-20m (30-70ft)

Width:

8-10m (25-30ft)

Hardiness:

Parts Used:

Leaves, leaf extract (paclitaxel), branches, twig tips.

Properties:

A bitter, astringent, purgative herb that contains extremely poisonous alkaloids and anti-cancer paclitaxel (taxol).

Medicinal Uses:

Internally, in the form of paclitaxel, for breast and ovarian cancers. Also in the form of a homeopathic tincture only, for bronchial and urinary problems, arthritis, gout and pustular skin diseases.
To treat epilepsy, worm infestastions, diphtheria, rheumatism, and liver ailments.

Possible Side Effects:

Yew's side effects include lowered blood pressure, irregular heartbeat, nausea, vomiting, allergic reactions, and joint and muscle pain.

Drug Interactions:

Taking yew with these drugs may interfere with the action of the drug:
Omeprazole, (Losec, Prilosec)	Pantoprazole, (Pantoloc, Protonix)	Ranitidine, (Alti-Ranitidine, Zantac)	Sucralfate, (Carafate, Sulcrate)

Taking yew with these drugs may worsen the drug's side effects and/or interfere with the drug's action:
Docetaxel, (Taxotere)	Paclitaxel, (Onxol, Taxol)	Tamoxifen, (Nolvadex, Tamofen)

Taking yew with these drugs may be harmful:
Ketoconazole, (Apo-Keoconazole, Nizoral)—may interfere with the metabolism of the drug.	Sucralfate, (Carafate, Sulcrate)—may interfere with the action of the drug.

Warning:

For use by qualified practioners only.
No longer used in herbal medicine due to its toxicity.
All parts, except aril, are extremely toxic if eaten.

Bibliography:

The Encyclopedia of Herbs by Deni Bown, Copyright © 1995, 2001 Dorling Kindersley Limited. pp. 383-384
The Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.505-506