Melochia corchorifolia (PROSEA)
Introduction |
- Protologue: Sp. pl. 2: 675 (1753).
- Family: Sterculiaceae
- Chromosome number: 2n= 46
Synonyms
- Melochia concatenata L. (1753).
Vernacular names
- Chocolate-weed, redweed (En)
- Indonesia: orang-aring (general), jaring (Sundanese), gendiran (Javanese)
- Malaysia: lemak ketam, lemak kepiting, bayam rusa (Peninsular)
- Philippines: bankalanan (Iloko), kalingan (Panay Bisaya)
- Thailand: khaang paak put (Chiang Mai), sa aeng bai mon (Chai Nat), seng lek (Ang Thong)
- Vietnam: trứng cua, v[ai]i giấy.
Origin and geographic distribution
Melochia consists of approximately 55 species and is largely confined to the tropics, although some species reach subtropical regions. The greatest diversity in species is found in Central and South America. Only 2 or 3 species are native to South-East Asia. M. corchorifolia is a weed throughout the tropics and subtropics, including South-East Asia. It originates from the Old World tropics and has been introduced in the Americas.
Uses
Traditional uses of M. corchorifolia in South-East Asia are only reported for Malaysia. The leaves are used for poulticing sores and swellings of the abdomen, and the sap is applied as an antidote to wounds caused by arrows poisoned with Antiaris toxicaria Lesch. Leaves and roots are used for poulticing in cases of smallpox. A decoction of the leaves and roots is used internally to treat dysentery, and a decoction of the leaves to stop vomiting. A leaf decoction is prescribed in a compound mixture against urinary disorders. A decoction of the plant is applied in folk medicine in India as a cure for abdominal swelling, dysentery and snake bites.
In Papua New Guinea, the leaves of an unidentified Melochia species are applied to the forehead to treat headache, and the fruit is eaten. The leaves of M. corchorifolia are sometimes eaten in Indo-China and India. The plant yields a beautifully silvery-white, fine and strong fibre, but in too small quantity to be important.
Properties
A phytochemical investigation of extracts from the dried, powdered aerial parts of M. corchorifolia revealed the presence of the triterpenes friedelin, friedelinol and β-amyrin, the sterol β-sitosterol together with its stearate and β-D-glucoside, the aliphatic compounds ethylstearate, tetratriacontanol, nonacosylnon-4-enoate, 24-ethyl-2-methyltritetracont-1-ene-3,23-diol and 27-methyloctacosane-1,3-diol and the flavonoids vitexin and robunin. Furthermore several alkaloids have also been reported in similarly prepared extracts: franganine, frangufoline adouetine-y' and melofoline (cyclopeptide alkaloids), melochicorine (a pseudo-oxindole alkaloid) and 6-methoxy-3-propenyl-2-pyridine carboxylic acid (a pyridine alkaloid). The latter compound may be of significance, since related pyridine derivatives (e.g. pyridoxine, 4'-methoxypyridoxine, nicotinic acid) are physiologically active. The flavonol glycosides hibifolin, triflin and melocorin have been isolated from the leaves.
The main alkaloid in M. pyramidata L., American in origin but naturalized in many tropical and subtropical regions including South-East Asia, is (-)-(R)-melochinine. This compound has been shown to produce paralysis, bradypnea, bradycardia and hypotension in laboratory animals, and ingestion of plant material by cattle may cause paralysis. The mechanism of action of this alkaloid can be described as in general non-specific. It may be partly explained by an unspecific interaction with membranes, partially responsible for a calcium-antagonistic effect. Unlike its structural analogue piercidin A, a well-known inhibitor of the mitochondrial respiratory chain, melochinine does not show insecticidal activity.
Description
- A perennial herb or subshrub up to 130 cm tall, erect or spreading and often widely branched, with tough bark.
- Leaves arranged spirally, simple, triangular or broadly ovate to lanceolate, lower leaves often slightly 3-lobed, 1-9 cm × 0.5-5 cm, margin crenate-serrate, 3-veined or 5-veined from the base, pubescent on the veins, green or with purplish tinge; petiole 0.3-4.5 cm long, sparsely pubescent to subvillose; stipules about 5 mm long, present on young twigs.
- Inflorescence an axillary or terminal head-like cyme, rarely less compact, subtended by 1-4 leaves with their stipules forming a kind of involucre, many-flowered.
- Flowers with pedicel bearing 3-4 pilose bracteoles at apex, bisexual, actinomorphic, 5(-7)-merous; calyx campanulate, about 2.5 mm long, with teeth much shorter than tube, pubescent; petals obovate-spatulate, 4-7 mm long, lilac or white with a yellow spot at base, soon withering; stamens opposite the petals, filaments connate to halfway or more, anthers broad, 2-lobed; ovary superior, 5-celled, densely pilose, each cell with 1-2 ovules, styles 5, united at base.
- Fruit a small globose capsule, 3.5-5 mm in diameter, green, whitish, pink to purplish-black, loculicidal but valves easily septicidal dehiscent, each cell 1-2-seeded.
- Seeds small, wingless; endosperm abundant; embryo straight, cotyledons flattened.
- Seedling with epigeal germination; cotyledons suborbicular, foliaceous.
Growth and development
M. corchorifolia is reported to flower and fruit all year round. The flowers are probably pollinated by small insects.
Other botanical information
M. corchorifolia is extremely variable morphologically and numerous varieties have been distinguished.
Roots of M. tomentosa L. have been used in Curaçao to relieve throat inflammation. However, the root extract was reported to be tumorigenic. M. umbellata (Houtt.) Stapf is a small tree indigenous from India to New Guinea for which no medicinal uses have been recorded.
Ecology
M. corchorifolia is a common weed in many regions in sunny or slightly shaded, usually humid localities, at watersides and in fields, waste places and open forest, up to 700 m altitude in Java. Although it is adapted to xerophytic conditions, M. corchorifolia has retained its ability to grow in mesophytic and hydrophytic habitats. In the Philippines, it is reported as one of the dominant weeds in upland rice, together with Echinochloa colona (L.) Link. In Thailand and Indonesia it is also a weed in lowland rice, moreover it is also recorded as such in soya bean.
Propagation and planting
Scarification of seed improves germination considerably. Scarified seed germinates best at a temperature of 35-40°C. Seed buried to a depth of 1-5 cm gave a germination rate of 80-90% after 7 days; when planted at the soil surface or deeper than 8 cm the seed did not germinate.
Genetic resources and breeding
Since M. corchorifolia shows a very extensive geographical distribution, occurring in anthropogenic habitats, it is not liable to genetic erosion.
Prospects
Although some research has been done on the phytochemistry, very little is known about the pharmacological properties and activity of M. corchorifolia and its compounds. The fact that tumorigenic and toxic activity has been reported from some other Melochia spp. should lead to caution in using M. corchorifolia in phytotherapy as so little is known about its biological activity.
Literature
- Bhakuni, R.S., Shukla, Y.N. & Thakur, R.S., 1986. 6-methoxy-3-propenyl-2-pyridine carboxylic acid: a new pyridine alkaloid from Melochia corchorifolia. Chemistry and Industry 1986(13): 464.
- Bhakuni, R.S., Shukla, Y.N. & Thakur, R.S., 1987. Chemical constituents of Melochia corchorifolia Linn. Indian Journal of Chemistry, section B, Organic Chemistry including Medicinal Chemistry, 26(12): 1161-1164.
- Bhakuni, R.S., Shukla, Y.N. & Thakur, R.S., 1987. Cyclopeptide alkaloids from Melochia corchorifolia. Phytochemistry 26(1): 324-325.
- Bhakuni, R.S., Shukla, Y.N. & Thakur, R.S., 1991. Melochicorine, a pseudooxindole alkaloid from Melochia corchorifolia. Phytochemistry 30(9): 3159-3160.
- Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. Vol. 2. Ministry of Agriculture and Cooperatives, Kuala Lumpur, Malaysia. p. 1472.
- Eastin, E.F., 1983. Redweed, Melochia corchorifolia, germination as influenced by scarification, temperature and seeding depth. Weed Science 31(2): 229-231.
- Goldberg, A., 1967. The genus Melochia L. (Sterculiaceae). Contributions from the United States National Herbarium 34(5): 191-363.
- Li, H.-L. & Lo, H.-C., 1993. Sterculiaceae. In: Huang, T.-C. (Editor): Flora of Taiwan. 2nd edition. Vol. 3. Editorial Committee of the Flora of Taiwan, Taipei, Taiwan, Republic of China. p. 764.
- Nair, A.G.R., Ramesh, P. & Subramanian, S.S., 1977. Melocorin, a new herbacetin glucuronide from Melochia corchorifolia. Indian Journal of Chemistry, section B, Organic Chemistry including Medicinal Chemistry, 15(11): 1045.
- Soerjani, M., Kostermans, A.J.G.H. & Tjitrosoepomo, G., 1987. Weeds of rice in Indonesia. Balai Pustaka, Jakarta, Indonesia. pp. 554-555, 640-641.
Other selected sources
- [97] Backer, C.A. & Bakhuizen van den Brink Jr, R.C., 1963-1968. Flora of Java. 3 volumes. Noordhoff, Groningen, the Netherlands. Vol. 1 (1963) 647 pp., Vol. 2 (1965) 641 pp., Vol. 3 (1968) 761 pp.
- [185] Breuer, H., Rangel, M. & Medina, E., 1982. Pharmacological properties of melochinine, an alkaloid producing Central American cattle paralysis. Toxicology 25: 223-242.
- [1126] 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.
- [1178] Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. 1262 pp.
Authors
- M.C. Ysrael