2935

12(3): Medicinal and poisonous plants 3

Taxus sumatrana (Miq.) de Laub.

Kalikasan 7: 151 (1978).

TAXACEAE

2n = unknown

Taxus wallichiana auct. non Zucc.

Indonesia: tampinur batu, kayu taji (Sumatra). Philippines: amugauen (Igorot).

Taxus sumatrana occurs scattered in the Malesian region. It has been found in Sumatra, the Philippines and Sulawesi. It is also recorded for the eastern Himalayas, northern Burma (Myanmar), Vietnam, southern China and Taiwan, but it depends on the taxonomic interpretation whether this concerns the same species or a closely related one.

Taxus sumatrana is not used in traditional medicine. Like other Taxus species, it is notorious for the substantial toxicity of all its parts, except the seed aril, for humans and animals (especially horses). However, branchlets and leaves of Taxus are used in Chinese traditional medicine to treat kidney diseases and diabetes. In India bark and leaves of Taxus are considered a remedy for cough, and in Nepal twigs and leaves are used as an emmenagogue.
The discovery in 1971 that Taxus is a source of taxol (paclitaxel), a compound with anticancer activity, increased the scientific interest dramatically and resulted at the beginning of the 1990s in the development of important drugs.
Taxus wood is highly valued and is used for decorative woodwork, such as chests and coffins, flooring, fence posts, mallots and bows. Taxus is an important ornamental, its dense growth and ability to withstand regular clipping making it suitable for hedges.

The most interesting compounds isolated from Taxus are diterpenes with a taxane nucleus. Some of these are strictly diterpenoids, e.g. baccatins, whereas others have an amide function, e.g. taxol. Taxol was first isolated from the bark of Taxus brevifolia Nutt. from the United States, but it is present only in traces, requiring enormous amounts of material for commercial exploitation. It appeared also possible to isolate taxol from the leaves of Taxus cultivars, and to prepare it from structural analogs present in substantial quantities (e.g. 10-desacetylbaccatin III). Taxol and related taxoids (e.g. baccatin III) have also been isolated from Taxus sumatrana leaves of Sumatran origin. Recently, good methods for producing taxol in in-vitro cell cultures have been developed, e.g. by adding methyl jasmonate, producing about 1 g of taxol in 10 l solution after 2 weeks.
Taxol is a mitotic spindle poison with very specific mode of action. It promotes the formation of microtubules and inhibits their disassembly into tubulin. Moreover, it inactivates the protein Bcl-2, which prevents apoptosis (programmed cell death). Taxol is given intravenously and is used to treat different types of tumours, including advanced ovary and breast cancer and certain lung cancers (non-small cell lung cancer) in patients who cannot have surgery or radiation therapy. It may also be used to treat AIDS-related Kaposi's sarcoma. Taxol may prolong the life of patients with advanced cancer (on average by 3 months in patients with advanced breast cancer). Side effects include reduction in white and red blood cell counts often resulting in infections, hair loss, nausea and vomiting, joint and muscle pain, nerve pain, numbness in the extremeties and diarrhoea. Taxotere (docetaxel) is another compound of special interest isolated from Taxus. Phase II/III clinical trials have established this compound as the most active single agent in the treatment of advanced metastatic breast cancer.
The constituents implicated in animal and human poisonings are taxines, alkaloids active on cardiac myocytes, resulting in heart failure and death in some instances.
The heartwood is reddish-brown and clearly distinct from the pale yellowish sapwood.

A dioecious, evergreen, large tree up to 45 m tall, with a bole diameter of over 100 cm; bark thin, smooth, purplish-red, peeling in large flakes. Leaves arranged spirally, but usually twisted into a single plane, simple and entire, linear-lanceolate to linear, 1.5—2.5 cm x 1.5—2 mm, distinctly constricted at base, acute at apex, decurrent. Pollen cones axillary, solitary, small, globular, with a basal cluster of sterile scales. Seed solitary in axil of leaf, with keeled scales at base, flask-shaped, c. 6 mm x 5 mm x 4 mm, covered by a fleshy, bright red aril when ripe.
Seeds germinate readily in moist and shady localities. Taxus sumatrana grows slowly. Seedlings grown in nurseries in Taiwan reached a maximum average height of 57 cm after 3 years. Pollination takes place by wind, whereas seeds are dispersed by birds, which eat the aril.
Taxus comprises about 7 closely related species, and occurs predominantly in temperate regions of the Northern hemisphere; only 1 species reaches highland regions of Malesia. Taxonomic studies of Taxus resulted in different classifications, one of them being a single, very widespread species with different subspecies. There are conflicting opinions concerning the taxa occurring in South-East Asia. Three species are recorded for this region: Taxus sumatrana, Taxus wallichiana Zucc. and Taxus chinensis (Pilger) Rehder, the latter 2 occurring in Vietnam. They are all very closely related, possibly conspecific, and more detailed studies are needed to clarify their taxonomy.

Taxus sumatrana occurs in montane forest and mossy forest at 1400—2300 m altitude, and is locally the dominant canopy species.

Taxus sumatrana has very scattered occurrence and in several regions is considered endangered, e.g. in Taiwan. This is due to its low reproduction rate and its highly valued wood. Its exploitation for taxol has been considered a serious danger to natural Taxus populations because of the enormous amounts of material needed and the slow growth rates, but this has been overcome by collecting prunings from cultivated plants and the development of techniques for in-vitro production of active compounds.
Many cultivars are planted as an ornamental in e.g. the United States, Canada and Europe. There is an excellent Taxus collection of various cultivars of most species at the Secrest Arboretum in Wooster, Ohio, United States.

It is unrealistic to expect that Malesian populations of Taxus sumatrana will play a role in the production of taxol or related compounds interesting for drug production. The species is too scarce in the region, cultivation is difficult because of altitudinal requirements, and other means of taxol production are becoming available, e.g. through in-vitro cell culture. Although Taxus sumatrana is an excellent timber tree, its occurrence is too scattered and it grows too slowly to be of future importance.

[118]Bruneton, J., 1995. Pharmacognosy, phytochemistry, medicinal plants. Technique & Documentation Lavoisier, Paris, France. 915 pp.
[247]Flora Malesiana (various editors), 1950—. Foundation Flora Malesiana. Rijksherbarium/Hortus Botanicus, Leiden, the Netherlands.
[484]Kitagawa, I., Mahmud, T., Kobayashi, M., Roemantyo & Shibuya, H., 1995. Taxol and its related taxoids from the needles of Taxus sumatrana. Chemical and Pharmaceutical Bulletin 43(2): 365—367.

[250]Flore du Cambodge, du Laos et du Viêtnam [Flora of Cambodia, Laos and Vietnam] (various editors), 1960—. Muséum National d'Histoire Naturelle, Paris, France.
[461]Ketchum, R.E., Gibson, D.M., Croteau, R.B. & Shuler, M.L., 1999. The kinetics of taxoid accumulation in cell suspension cultures of Taxus following elicitation with methyl jasmonate. Biotechnology and Bioengineering 62(1): 97—105.
[564]Lin, S.-T. & Chien, W.-T., 1997. Silvicultural studies on Taiwan yew (Taxus sumatrana). (II) Effects of different light quantum regimes on the seedling performance of Taiwan yew. Quaterly Journal of the Experimental Forest of National Taiwan University 11(1): 81—98 (in Chinese).
[599]Mantle, D., Lennard, T.W. & Pickering, A.T., 2000. Therapeutic applications of medicinal plants in the treatment of breast cancer: a review of their pharmacology, efficacy and tolerability. Adverse Drug Reactions and Toxicological Reviews 19(3): 223—240.
[1001]Wilson, C.R., Sauer, J. & Hooser, S.B., 2001. Taxines: a review of the mechanism and toxicity of yew (Taxus spp.) alkaloids. Toxicon 39: 175—185.
[1046]Yukimune, Y., Hara, Y., Nomura, E., Seto, H. & Yoshida, S., 2000. The configuration of methyl jasmonate affects paclitaxel and baccatin III production in Taxus cells. Phytochemistry 54(1): 13—17.

F.C. Pitargue

Pitargue, F.C., 2003. Taxus sumatrana (Miq.) de Laub.. In: Lemmens, R.H.M.J. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(3): Medicinal and poisonous plants 3. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea