Carpon Desmodium

Overview

Native to South-East Asia, Grona heterocarpos is distributed naturally from India and Sri Lanka through Burma, Thailand, Indo-China, Malesia, China, Taiwan, Ryukyu, Japan, to the Pacific Islands and Australia.The plant is harvested from the wild for local use as a medicine. The plant is used as a cover crop for erosion and weed control in tree plantations, with the potential for use as a green manure. It has possible use in agro-forestry systems due to its shade tolerance and comparatively shallow rooting. It can be used for cut-and-carry and for the restoration of degraded soils.

Vernacular Names

Rumput kerbau derapah (Malaysia), Mangkit-parang (Tagalog-Philippines), Baay dâm'nnaëp (Cambodian), Tra[n]g qu'a di qu'a (Vietnamese), Jia di dou (Chinese). 

Agroecology

Found on grasslands, grassy slopes, watersides, thickets, and forests. A plant of the moist tropics and subtropics, where it is found at elevations up to 1,000 metres. It grows best in areas where annual daytime temperatures are within the range 14-24 °C, but can tolerate 4-34 °C. It prefers a mean annual rainfall in the range 2,000-3,000 mm, but tolerates 1,000-4,000 mm, and a weak dry season of no more than 3-4 months. Prefers light shade, doing well in full sun and tolerating quite deep shade. Tolerant of a wide range of soils, succeeding in low fertility and able to grow with high levels of aluminium or manganese. Plants have a good tolerance of waterlogging and periodic inundation of the soil. Prefers a pH in the range 4.5-6.5, tolerating 4-7.

Morphology

• Stems - much-branched at the base, and when young variously hairy, from almost glabrous to densely covered with more or less appressed hairs.
• Leaves - with 3 leaflets, or often with 1 leaflet on seedlings or at the base of older stems; leaflets variable in texture, shape and size, mostly papery; the terminal one elliptical, ovate or obovate, (1.5-)2-6(-9) cm × (1-)1.5-3(-4) cm, indented or more or less pointed at the tip, sparsely covered with appressed hairs on the upper surface, the lower surface more densely covered with appressed silvery hairs and with prominent nerves; the lateral ones with the same proportions but up to 4 cm long.
• Flower - inflorescence a dense axillary or terminal raceme; flowers pink, mauve, purple, violet or white, 4-7 mm long, mostly in pairs, each on a 3-5 mm long pedicel within the axil of a 5-8 mm long pointed bract.
• Fruit - pod 10-28 mm × 2-3 mm, erect to ascending, straight along the upper margin, undulate along the lower margin, the isthmus between the 4-8 articles 2/3-4/5 as wide as the pod which splits along the lower margin when ripe; articles quadrate, 2.5-3 mm long, glabrous or hairy.
• Seed - broadly elliptical, 1.5 mm × 2 mm.

Cultivation

• Generative propagation is by seed - best sown as soon as it is ripe. Stored seed develops a hard seedcoat and may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12-24 hours in warm water. The seed usually germinates within 1-4 months at 25 °C. Prick out the seedlings into individual pots once they are large enough to handle and grow them on until large enough to plant out. 
• Vegetative propagation is by cuttings (of half-ripe wood with a heel and roots), and by division. Larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on until they are rooting well.

Chemical Constituents

Betulic acid, friedelin, n-hexadecanoic acid, β-sitosterol, (Z,Z)-9,12-octadecadienoic acid,1-hentetracontanol, octacosane, vitexin, isovitexin2-carboxy-dihydrostilbene glucoside, 2-carboxy-3,5,4′, trihydroxydihydrostilbene 3-O-β-d-glucopyranoside, lunularic acid 4′-O-β-d-glucopyranoside, (−)-epi-catechin 3-O-β-d-glucopyranoside, and (−)-epi-afzelachin 3-O-β-d-glucopyranoside.

Traditional Medicinal Uses

• Boiled roots used as poultice for sore breasts.
• Plant decoction considered tonic and useful for coughs.
• In West Java (Indonesia), roots and leaves used for women's problems.
• Santals use a plant preparation for fainting and convulsions.
• Plant used for reducing fever and treating contusions and strains.
• Studies have shown antimicrobial, antioxidant, and cytotoxic properties.