Cyathostemma argenteum (Bl.) J. Sinclair

Cyathostemma argenteum (Bl.) J. Sinclair

[From Latin, argentum = silver]

Synonymy: Uvaria micrantha Hook. f. & Thoms.

Physical description: It is a rainforest climber of Malaysia and Indonesia.The young stems are rufous-pubescent. Leaves: simple, alternate and exstipulate.The blade is oblong-lanceolate, 10 cm–17 cm×4 cm–6 cm, slightly silvery- grey puberulous beneath and glabrous above, except the midrib. The base of the blade is broad, round, truncate and the apex is shortly and obtusely acuminate. The petiole is 3 mm–5 mm long. The flowers are dark purple. The corolla consists of 6 petals which are broadly ovate, obtuse, 5 mm long, imbricate, pubescent and inflexed at the apex. The calyx comprises of 3 sepals which are broadly ovate, obtuse, and 2 mm long. The fruits are sausage-shaped and 2cm×4cm.

Pharmaceutical interest:

Antispasmodic properties: Isoquinoline alkaloids in Cyathostemma argenteum (Bl.) J. Sinclair and in other Annonaceae probably explain the frequent use of these plants to stop spasms. One such alkaloid, from Fissistigma glaucescens, is (-)-discretamine which inhibits, experimentally, the contraction of rat aorta induced by noradrenaline, phenylephrine, and clonidine. (-)-Discretamine inhibits the irreversible blockade of α-adrenoreceptors by phenoxybenzamine and inhibits the formation of [3H]-inositol monophosphate caused by noradrenaline, appearing, therefore, as a selective α1-adrenoreceptor blocking agent. (-)-Discretamine blocks non-competitively 5-hydroxytryptamine (5HT) receptors (Ko FN et al., 1994).

Cytotoxic properties: (-)-Discretamine inhibits the proliferation of brine shrimps (LC₅₀ > 125 μg/mL) less efficiently than emetine (LC50: 30μg/mL; Khamis SB et al., 1998). Cyathostemmine, from Cyathostemma viridifolium, inhibits the proliferation of KB cells cul- tured in vitro (IC₅₀ = 4.5 μg/mL; Mahmood K et al., 1993).

Uses: In Indonesia, the bark is used to stop spasms and to soothe inflamed parts. The flowers are used to treat malaria, and the seeds are eaten to assuage stomach discomfort and to combat fever. In Malaysia, a paste of the fresh flowers is applied to the chest to treat asthma. In the Solomon Islands, a paste of the leaves is used externally to heal boils. In India, the essential oil makes an external remedy used to treat cephalgia, ophtalmia and gout.

References

Khamis SB, et al. (1998) J Pharm Pharmacol 50: 281. Ko NK, et al. (1993) Br J Pharmacol 110: 882–888. Mahmood K, et al. (1993) Nat Prod Lett 3: 245–249.

Warning: Caution must be taken as the toxic effects of this plant are unknown.

Soure: MEDICINAL PLANTS OF THE AISA-PACIFIC: DRUGS FOR THE FUTURE