Streptocaulon (PROSEA)
Introduction |
Streptocaulon Wight & Arnott
- Protologue: Wight, Contr. bot. India: 64 (1834).
- Family: Asclepiadaceae
- Chromosome number: x= unknown
Origin and geographic distribution
Streptocaulon comprises approximately 5 species, which all occur in tropical Asia. Thailand seems richest, with 3 species.
Uses
Streptocaulon roots are fairly widely used in Indo-China, southern China and Thailand, mainly to treat fever and dysentery, as a rejuvenating drug and as a tonic for kidneys and liver. The leaves are applied to snake bites and abscesses, whereas the latex is used as a vulnerary in the Philippines. S. baumii is in demand as raw material for baskets and other handicrafts in the Philippines.
Properties
General screening of S. juventas roots showed the presence of starch and alkaloids.
Botany
Lianas or shrubs with twining stems; white latex present. Leaves opposite, simple and entire, herbaceous to leathery, glabrous to densely hairy, with pinnate venation, with minute trichomes, often shortly petiolate; stipules absent. Inflorescence an extra-axillary or terminal, often lax and irregularly forked, paniculiform cyme. Flowers bisexual, regular, 5-merous, small; calyx small, with minute glands at base of the lobes; corolla rotate, with short tube and large lobes overlapping to the right in bud; corona lobes inserted on the corolla, adnate to the filaments, slender, inflexed; stamens inserted at base of corolla, shortly connate at base, alternating with minute teeth, anthers connivent and adnate to the stigma head, with short, apical membrane, with pollen tetrads in solitary masses in each anther cell; ovaries 2, free, superior, 1-celled, stigma head convex, angular. Fruit consisting of 2 divaricate follicles, cylindrical to ovoid, finely warty, many-seeded. Seeds oblong, comose.
Ecology
Streptocaulon usually occurs in lowland forest, often at edges and in open localities, and in thickets.
Management Streptocaulon is rarely cultivated. The tuberous roots of S. juventas are usually collected from the wild. In Vietnam they are harvested year-round, but preferably in autumn. After collecting, they are well washed, sliced and dried in the sun or in ovens.
Genetic resources
In most regions where Streptocaulon occurs it is collected from wild populations for medicinal applications and sometimes also for basketry. The plants are often killed during collection and therefore Streptocaulon may become threatened in the near future.
Prospects
Streptocaulon is fairly widely used in traditional medicine in Vietnam, southern China, as well as Thailand, but almost no research has been done on the phytochemistry and pharmacological properties. This should be given more attention, and if suitable cultivation methods can be developed, Streptocaulon may have prospects as a valuable medicinal plant for wider use in South-East Asia, including the Malesian region.
Literature
172, 760, 1008.
Selection of species
Authors
Wongsatit Chuakul, Noppamas Soonthornchareonnon & Orawan Ruangsomboon