Hygrophila ringens (PROSEA)
Introduction |
Hygrophila ringens (L.) R.Br. ex Steudel
- Protologue: Nomencl. bot., ed. 2, 1: 783 (1840).
- Family: Acanthaceae
- Chromosome number: 2n= 32, 44
Synonyms
Hygrophila angustifolia R.Br. (1810), Hygrophila quadrivalvis (Buch.-Ham.) Nees (1832), Hygrophila salicifolia (Vahl) Nees (1832), Hygrophila erecta (Burm.f.) Hochr. (1934).
Vernacular names
- Malaysia: keremak, chukal, maman babi (Peninsular)
- Philippines: binakag (Iloko), kangon-kangon, mamitik (Tagalog)
- Thailand: toiting (Bangkok), nam dap fai (Prachuap Khiri Khan), sam sam (Loei)
- Vietnam: cây hạt phỏng.
Origin and geographic distribution
H. ringens has a wide area of distribution: from India and Sri Lanka, through Indo-China, southern China and Japan, to Thailand and the Malesian region, where there are records from Peninsular Malaysia, Singapore, Java, Borneo and the Philippines, but it probably also occurs elsewhere.
Uses
In Peninsular Malaysia, the leaves are applied as a poultice to treat wounds, swellings, boils and headache, and also to treat toothache. The seeds are used by the cosmetic and pharmaceutical industry, particularly in central Europe, as a skin-regenerating product. The leaves may be eaten as a vegetable.
H. schulli (Buch.-Ham.) M.R. Almeida & S.M. Almeida (synonyms: H. auriculata (Schum.) Heine, H. spinosa T. Anderson) is used in traditional medicine in India and Burma (Myanmar), e.g. to treat liver ailments and spermatorrhoea. In Africa, particularly the roots are applied in the treatment of blennorrhoea, dropsy, anuria, hepatic obstruction and rheumatism. H. schulli , which is accredited in India and Africa with diuretic properties, has once been recorded for Malesia (Singapore).
Some Hygrophila species are cultivated as ornamental aquatic plants in aquaria. Several species are weeds, often in rice fields.
Properties
Lipophilic extracts of H. ringens seeds possess neurotrophic activities. They showed a striking effect on the morphological differentiation of cerebral neurons of rat embryos in vitro, and proved to attenuate the degeneration of cholinergic neurons after injury. They also had interesting properties on mice resident peritoneal macrophages by provoking significant morphological changes and by increasing their phagocytosis capacity. A long-chain aliphatic alcohol, n-hexacosanol, proved to be responsible for these activities.
A significant hepatoprotective activity of a methanolic extract of H. schulli seeds was reported from tests with rats in India. Studies with rats suggest that an aqueous extract of the same species may exert hypoglycaemic action by mechanisms similar to those of the sulphonylureas. In tests with mice, a petroleum ether extract of the root of H. schulli potentiated the sedative-hypnotic action of chlorpromazine, diazepam, pentobarbitone and chlordiazepoxide, and protected against strychnine-induced convulsions. This extract also exhibited haematinic effect in rats and antitumour activity in Ehrlich ascites carcinoma and sarcoma-180 bearing mice.
Botany
An erect or ascending annual or short-living herb up to 90(-120) cm tall; stem rooting at the lower nodes, subquadrangular. Leaves decussately opposite, simple, linear-oblong to elliptical-oblong or elliptical-obovate, 1-16 cm × 0.5-5 cm, tapering into petiole at base, acute or obtuse at apex, margin entire to crenulate or undulate, irregularly marked with cystoliths; stipules absent. Inflorescence a dense axillary cluster, conspicuously bracteate. Flowers bisexual, 5-merous; calyx 6-12 mm long, with unequal linear-lanceolate lobes; corolla with ventricose, puberulent tube 7-10 mm long, 2-lipped, upper lip c. 5 mm long, 2-fid, lower lip c. 5 mm long, pale violet-blue or whitish; stamens 4, didynamous, inserted below the middle of the corolla tube; ovary superior, 2-celled, style slender, often with 2 teeth at apex. Fruit a linear-oblong to linear-ovoid loculicidal capsule 1-2 cm long, many-seeded. Seeds globose-ovoid, subcompressed, c. 1.5 mm long, long-hairy.
H. ringens is an extremely variable species, and is often split up into several species, particularly on the shape of the leaves. A taxonomic account of Hygrophila is needed to confirm the broad concept of H. ringens as adopted here.
Hygrophila comprises approximately 80 species, and occurs in Africa and Asia, mainly in the tropics. Africa is richest in species (about 45). There are a handful of species in Malesia.
Ecology
H. ringens occurs in swampy or periodically humid localities, e.g. at watersides, from sea-level up to 1000 m altitude.
Management In tests, the production of n-hexacosanol in tissue cultures of H. ringens was not successful, but verbascoside was a major extractable metabolite in callus and cell suspension cultures. This latter compound has antimicrobial properties.
Genetic resources
H. ringens is widely distributed and is not easily liable to genetic erosion. Its extreme morphological variability should be investigated.
Prospects
The uses of H. ringens in traditional medicine in South-East Asia as a poultice seem to agree to some degree with the interest of the European cosmetic and pharmaceutical industry in this species as a skin-regenerating product. More research on pharmacological activity may show that it is a promising medicinal plant for primary health care in South-East Asia. Research on H. schulli , which is a well-known medicinal plant in India, might also be worthwhile. Neither propagation nor cultivation will be a major impediment.
Literature
64, 121, 644.
Other selected sources
62, 120, 243, 283, 613, 614, 782, 861.
Main genus page
Authors
R.H.M.J. Lemmens