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<big>''[[Platycladus orientalis]]'' (L.) Franco</big>
__NOTOC__
:Protologue: Portugaliae Acta Biol., Sér. B, Sist. Vol. "Julio Henriques": 33 (1949).
:Family: Cupressaceae
:Chromosome number: 2''n''= 22
Platycladus orientalis (L.) Franco - 1, fruiting twig; 2, detail of shoot
== Synonyms ==
== Properties ==
The leaves and fruits of ''P. orientalis'' contain an essential oil which can be easily obtained by steam distillation. The leaf essential oil contains high amounts ofαof α-pinene,β-caryophyllene, cedrol,β-myrcene, R-(+)-limonene and aloaromadendrene. The essential oil from the fruits contains high amounts ofαof α-pinene,δ-3-carene,β-terpinene, rho-cymene, cedrol, camphene, D-limonene and myrtenol. In Egyptian material the highest yield was obtained from fresh fruits (0.32 % v/w).
Furthermore, a labdane-type diterpene, pinusolide was isolated from the hexane and chloroform extracts of the leaves of ''P. orientalis'' . Pinusolide is a potent platelet activating factor (PAF) receptor-binding antagonist, which inhibited PAF-induced aggregation of rabbit platelets (IC<sub>50</sub>value of 5μM5 μM), but had no inhibitory effect on ADP-, thrombin-, or collagen-induced platelet aggregation. Pinusolide also protected mice from PAF-induced lethality (ED<sub>50</sub>values of 1.1 mg/kg, intravenous, and 69 mg/kg, per oral). Topical administration of pinusolide, at 2 mg/ear, was effective in inhibiting croton oil-induced mouse ear oedema. Ears of treated mice fully recovered, in contrast to the necrotized ears of their untreated controls.
The effects of pinusolide on PAF-induced [3H]serotonin release from rabbit platelets, hypotension and vascular permeability were furthermore confirmed. Pinusolide (IC<sub>50</sub>, about 5 x 10<sup>-6</sup>M) inhibited specifically [3H]serotonin release from rabbit platelets when stimulated with PAF (5 x 10<sup>-8</sup>M), but showed no effect when induced by ADP, collagen and thrombin. It also inhibited PAF-induced hypotension in a dose-dependent manner in rats with no effect on the hypotension induced by acetylcholine, histamine and serotonin. The inhibitory effect of pinusolide on the PAF-induced vascular permeability is less specific than the induced hypotension. The results suggest that pinusolide may prove of therapeutic value in the treatment of hypotension and a molecular design of pinusolide analogues may provide the possibility of new PAF specific antagonists.
The related compound pinusolidic acid, obtained from the CHCl<sub>3</sub>extract of ''P. orientalis'' , also inhibited PAF-induced aggregation of rabbit platelets (IC<sub>50</sub>value of 2.3 x 10<sup>-5</sup>M).
In an experiment with mice, an ethanol extract of the seeds of ''P. orientalis'' was investigated for its effect on learning impairment, produced by bilateral lesion of basal forebrain, and judged by performance in the step-through and step-down type passive avoidance tests. Chronic oral administration of the ethanol extract at a daily dose of 250 or 500 mg/kg, from the day of surgery until the end of the behavioural test, dose-dependently improved memory acquisition impairment in the step-down test, and memory retention disturbance in both behavioural tasks. Other effects of extracts include the haemostatic properties of the leaves, which are confirmed in a series of experiments in rabbits and dogs, aqueous and ethanolic extracts which showed marked in vitro and in vivo antitumour activity, and a decoction of the leaves which is reported as having an activity similar to that of vitamin K.
Immunosuppressant activity was observed in mice fed with a diet containing 10% seed oil.
== Description ==
The potential for cultivation of ''P. orientalis'' in South-East Asian countries especially at higher elevations needs further investigation. Pinusolide shows interesting activity in the field of hypertension and platelet activating factor (PAF-)antagonism. Although more research will be needed, the compound or its (semi-)synthetic analogues may have some potential in future medicinal research.
== Literature ==
== Other selected sources ==
* [135] Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A-HA—H) pp. 1-12401—1240, Vol. 2 (I-ZI—Z) pp. 1241-24441241—2444. *[215] Council of Scientific and Industrial Research, 1948—1976. The wealth of India: a dictionary of Indian raw materials & industrial products. 11 volumes. Publications and Information Directorate, New Delhi, India.*[263] Doan Thi Nhu, Do Huy Bich, Pham Kim Man, Nguyen Thuong Thuc, Bui Xuan Chuong & Pham Duy Mai (Editors), 1990. Les plantes médicinales au Vietnam. Livre 2. Médicine traditionelle et pharmacopée [The medicinal plants of Vietnam. Volume 2. Traditional medicine and pharmacopoeia]. Agence de coopération Culturelle et Technique, Paris, France. 189 pp.*[296] Farjon, A., 1998. World checklist and bibliography of conifers. Royal Botanic Gardens, Kew, United Kingdom. 298 pp.*[312] Flore du Cambodge, du Laos et du Viêtnam [Flora of Cambodia, Laos and Vietnam](various editors), 1960—. Muséum National d'Histoire Naturelle, Paris, France.*[562] Kosuge, T., Yokota, M., Yoshida, M. & Ochiai, A., 1981. Studies on antihaemorrhagic principles in crude drugs used for haemostasis. I. Haemostatic activities. Yakugaku Zasshi 101(6): 501—503. (in Japanese)*[577] Lai, L.T., Naiki, M., Yoshida, S.H., German, J.B. & Gershwin, M.E., 1994. Dietary Platycladus orientalis seed oil suppresses anti-erythrocyte autoantibodies and prolongs survival of NZB mice. Clinical Immunology and Immunopathology 71(3): 293—302.*[739] Nguyen Van Duong, 1993. Medicinal plants of Vietnam, Cambodia and Laos. Mekong Printing, Santa Ana, California, United States. 528 pp.*[786] Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. 620 pp.*[928] Singh, P. & Sinha, K.K., 1986. Inhibition of aflatoxin production on some agricultural commodities through aqueous plant extracts. Journal of the Indian Botanical Society 65(1): 30—32.
== Authors ==
*S. Aggarwal
[[Category:Medicinal plants (PROSEA)]]
[[Category:PROSEA]]
