Asystasia gangetica (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Vegetable
Carbohydrate / starch
Medicinal
Ornamental
Forage / feed
Food security

distribution in Africa (wild)

1, flowering and fruiting branch; 2, flower in longitudinal section; 3, dehisced fruit. Source: PROSEA

flower

flowering plant habit

Asystasia gangetica (L.) T.Anderson

Protologue: Thwaites, Enum. pl. zeyl.: 235 (1860).

Family: Acanthaceae

Chromosome number: 2n = 26, 52

Synonyms

• Asystasia coromandeliana Nees (1832).

Vernacular names

• Tropical primrose, Chinese violet (En).
• Herbe le rail, mange-tout, herbe pistache, pistache marron (Fr).
• Asistasía branca (Po).
• Fuchwe, mtikini, kichwamangwo (Sw).

Origin and geographic distribution

Asystasia gangetica is native in tropical Africa, Arabia and tropical Asia, but has been introduced in many other tropical regions, where it often naturalized. It occurs throughout tropical Africa.

Uses

Asystasia gangetica is locally used as a potherb and leafy vegetable, mainly in times of scarcity. In Kenya and Uganda it is locally a popular vegetable, mixed with beans and groundnut or sesame paste. It is also often prepared in a mix with other leafy vegetables. Asystasia gangetica is sometimes promoted as a cover plant in orchards because it checks erosion and prevents infestation by noxious weeds, and because it attracts bees to the orchard. Because of its ability to grow under shade and its high nutritive value, Asystasia gangetica is used as a forage for cattle, goats and sheep in South-East Asia; it is either grazed or cut for stall feeding. Excessive consumption by sheep can result in bloat.

In Africa an infusion of the plant is used to ease pain during childbirth, and the sap is applied to sores, wounds and piles, and in embrocations to treat stiff neck and enlarged spleen in children. Powdered roots are considered analgesic and used in treating stomach-ache and snakebites. A leaf decoction is used as analgesic and to treat epilepsy and urethral discharge. In Nigeria the leaves are used to treat asthma. In India the sap is applied to swellings; it is also used as a vermifuge and to treat rheumatism. In the Moluccas (Indonesia) the juice, together with lime and onion juice, is recommended for dry coughs with an irritated throat and discomfort in the chest. In the Philippines the leaves and flowers are used as an intestinal astringent. In Tanzania plants are pounded with water to make a wash against fleas for young animals. Asystasia gangetica is occasionally planted as an ornamental.

Properties

The nutritional composition of Asystasia gangetica leaves per 100 g edible portion is: water 82.6 g, energy 234 kJ (56 kcal), protein 3.7 g, fat 1.2 g, carbohydrate 10.4 g, Ca 226 mg, P 30 mg, Fe 4.7 mg, carotene 6250 μg, thiamin 0.19 mg, riboflavin 0.21 mg, niacin 1.0 mg, ascorbic acid 42 mg (Leung, W.-T.W., Butrum, R.R. & Chang, F.H., 1972). Extracts of Asystasia gangetica have shown analgesic and anti-asthmatic properties in pharmacological tests.

Adulterations and substitutes

Asystasia mysorensis (Roth) T.Anderson is used as a substitute for Asystasia gangetica, as are several Justicia species.

Description

• Perennial herb, with usually ascending, branched, quadrangular stem up to 2 m long, often rooting at the lower nodes.
• Leaves opposite, simple; stipules absent; petiole 0.5–6 cm long; blade ovate to lanceolate, 3–8(–13) cm × 1.5–4.5(–7) cm, base cuneate to cordate, apex acuminate or acute, margin entire, glabrous to sparsely pubescent, with 4–6 lateral veins at each side of the midrib, provided with cystoliths.
• Inflorescence a terminal raceme up to 25 cm long, with flowers directed to one side.
• Flowers bisexual, slightly zygomorphic, 5-merous; pedicel up to 3 mm long; calyx with lanceolate lobes 4–10 mm long; corolla funnel-shaped, up to about 2.5(–4) cm long, usually white with purplish spots inside lower lobe, with rounded lobes c. 1 cm wide, lower lobe slightly longer; stamens 4, 2 shorter and 2 longer; ovary superior, densely pubescent, 2-celled, style up to 1.5(–2) cm long, stigma with 2 short lobes.
• Fruit a club-shaped capsule 2–3 cm long, pubescent and glandular, usually 4-seeded.
• Seeds ovoid, flattened, 4–5 mm long, grey to brown, with crenate margins, tuberculate, supported by retinacula.

Other botanical information

Asystasia comprises about 50 species, and is distributed in the tropics of the Old World, with about 30 species in tropical Africa. Two subspecies can be distinguished within Asystasia gangetica.

• Subsp. micrantha (Nees) Ensermu, with corolla normally less than 2.5 cm long and style less than 1.5 cm long, is diploid (2n = 26) and distributed in tropical Africa, the Indian Ocean islands and Arabia.
• Subsp. gangetica, with corolla normally more than 2.5 cm long and style more than 1.5 cm long, is tetraploid (2n = 52) and distributed in India, Sri Lanka, South-East Asia and islands of the Pacific Ocean, and introduced in tropical America. Both subspecies can be weedy, but subsp. micrantha is more serious as it is more vigorous and tends to become decumbent, producing a dense carpet of rooting stems and foliage.

Growth and development

The period from seedling emergence to seed dispersal can be as short as 8 weeks in open areas, but it can take 2 weeks longer in partially shaded areas. It takes one month from flower development to seed dispersal. The seeds are thrown as far as 6 m by an explosive opening mechanism of the fruits, triggered by hot afternoons.

Asystasia gangetica is a shade-loving plant and optimum photosynthesis occurs between 30% and 50% full sunlight. With no weeding, its proportion in the undergrowth of a young oil palm plantation increased in a period of 2 years from 25% to 84%. It grows, though slowly, under a closed canopy of oil palm with less than 10% full sunlight.

Ecology

Asystasia gangetica is found along roadsides and river banks, in more or less waterlogged areas as well as well-drained cultivated areas, from sea-level up to 2500 m altitude. In areas with a dry season of 4 months or more it may not survive. It thrives on coastal alluvium, peat soils with 85% organic matter and pH 3.5–4.5, sandy loams and clay soils.

Propagation and planting

Asystasia gangetica can be propagated by seed and stem cuttings with 1–3 nodes. Single-node cuttings buried in soil produce flowers and fruits within 6 weeks.

Management

Its agressiveness, high uptake of soil nutrients and ability to smother other species have characterized Asystasia gangetica as a weed in plantation management. However, the high palatability and digestibility of Asystasia gangetica make it attractive to grazing animals as plantation undergrowth.

Diseases and pests

Asystasia gangetica is susceptible to the fungus Colletotrichum dematium, which causes necrosis, defoliation and stunted growth. In West Africa it was observed as a host plant for a mottle virus, transmitted by aphids.

Harvesting

Young tender leaves and shoots of Asystasia gangetica are collected as a vegetable. Frequent cutting for stall feeding induces early dieback because the stems have long internodes and growing points higher up the stems. Low grazing pressures or long intervals between grazing allow the plant to flower and set seed. It is usually consumed fresh by animals but it can be conserved as hay if properly dried.

Yield

For Asystasia gangetica grown under heavy shade (6–16% full sunlight) dry matter yields of 2–5 t/ha have been recorded, but under a more open canopy of Leucaena leucocephala (Lamk) de Wit at 2 m × 1 m spacing, yields of 3.5–8 t/ha were obtained. Cattle production in the range of 110–135 kg/ha per year, equivalent to 270–310 g/head per day, can be achieved from native forages mixed with Asystasia gangetica grown under oil palm.

Handling after harvest

Asystasia gangetica leaves can be dried, pounded, and the powder stored for use in the dry season.

Genetic resources

There are no known germplasm collections of Asystasia gangetica and no breeding programmes. It is not at risk of genetic erosion. More attention to its different types may be desirable, focusing on vegetable use, forage use, medicinal properties, weedy characteristics and ornamental value.

Prospects

Asystasia gangetica may have potential and warrants research as a nutritious vegetable, as an auxiliary plant in agriculture and as a forage plant. It may be used as a substitute for legumes in the production of leaf meal. However, the spreading of some types as a serious weed needs attention.

Major references

• Adetula, O.A., 1987. Distribution and cytomorphology of Asytasia calycina Bentham and A. gangetica (L.) T. Anderson (Acanthaceae) in Nigeria. MSc Dissertation, University of Lagos, Akoka, Lagos, Nigeria.

• Ensermu Kelbessa, 1994. A revision of Asystasia gangetica (L.) T.Anders. (Acanthaceae). In: Seyani, J.H. & Chikuni, A.C. (Editors). Proceedings of the 13th plenary meeting of AETFAT, Zomba, Malawi, 2-11 April 1991. Volume 1. Plants for the people. National Herbarium and Botanic Gardens of Malawi, Zomba, Malawi. pp. 333–346.

• Kang, L.C., 1981. Asystasia. Nature Malaysiana 6(2): 14–17.

• Katende, A.B., Ssegawa, P. & Birnie, A., 1999. Wild food plants and mushrooms of Uganda. Technical Handbook No 19. Regional Land Management Unit/SIDA, Nairobi, Kenya. 490 pp.

• Lee, S.A. & Chen, C.P., 1992. Asystasia gangetica (L.) T. Anderson. In: ’t Mannetje, L. & Jones, R.M. (Editors). Plant Resources of South-East Asia No 4. Forages. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 51–53.

• Leung, W.-T.W., Butrum, R.R. & Chang, F.H., 1972. Food composition table for use in East Asia. Department of Health, Education and Welfare, Bethesda, United States. 334 pp.

• Maundu, P.M., Ngugi, G.W. & Kabuye, C.H.S., 1999. Traditional food plants of Kenya. Kenya Resource Centre for Indigenous Knowledge (KENRIK), Nairobi, Kenya. 270 pp.

• Sri Endreswari, 2003. Asystasia Blume. In: Lemmens, R.H.M.J. & Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No 12(3). Medicinal and poisonous plants 3. Backhuys Publishers, Leiden, Netherlands. pp. 86–88.

• Ugborogho, R.E. & Adetula, O.A., 1988. The biology of the Asystasia gangetica complex (Acanthaceae) in Lagos state, Nigeria. Feddes Repertorium 99(11–12): 507–517.

• van der Zon, A.P.M. & Grubben, G.J.H., 1976. Les légumes-feuilles spontanés et cultivés du Sud-Dahomey. Communication 65. Département des Recherches Agronomiques, Koninklijk Instituut voor de Tropen, Amsterdam, Netherlands. 111 pp.

Other references

• Adetula, O.A., 1985. Cytotaxonomic studies of Asystasia gangetica (L.) T.Anderson (Acanthaceae) in Lagos State. BSc thesis, University of Lagos, Akoka, Lagos, Nigeria.

• Akah, P.A., Ezike, A.C., Nwafor, S.V., Okoli, C.O. & Enwerem, N.M., 2003. Evaluation of the anti-asthmatic property of Asystasia gangetica leaf extracts. Journal of Ethnopharmacology 89(1): 25–36.

• Bosser, J. & Heine, H., 2000. Acanthacées. In: Bosser, J., Cadet, T., Guého, J. & Marais, W. (Editors). Flore des Mascareignes. Familles 127–135. The Sugar Industry Research Institute, Mauritius, l’Institut pour le Développement (IRD), Paris, France & Royal Botanic Gardens, Kew, Richmond, United Kingdom. 42 pp.

• Kiew, R. & Vollesen, K., 1997. Asystasia (Acanthaceae) in Malaysia. Kew Bulletin 52(4): 965–971.

• Rajaratnam, J.S., Chan, K.W. & Ong, H.T., 1976. Asystasia in oil palm plantations. In: Earp, D.A. & Newell, W. (Editors): International developments in oil palm. Proceedings of the Malaysian international agricultural oil palm conference, Kuala Lumpur, 14-17 June 1976. Incorporated Society of Planters, Kuala Lumpur, Malaysia. pp. 454–470.

• Tan, T.K. & Tow, S.A., 1994. First record of Colletotrichum dematium as a pathogen of Asystasia nemorum and A. gangetica in Singapore. Plant Pathology 43(4): 762–766.

• Yeoh, H.H. & Wong, P.F.M., 1993. Food value of lesser utilized tropical plants. Food Chemistry 46(3): 239–241.

Sources of illustration

• Lee, S.A. & Chen, C.P., 1992. Asystasia gangetica (L.) T. Anderson. In: ’t Mannetje, L. & Jones, R.M. (Editors). Plant Resources of South-East Asia No 4. Forages. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 51–53.

Author(s)

• O.A. Adetula, National Horticultural Research Institute (NIHORT), P.M.B. 5432, Idi-Ishin, Jericho, Ibadan, Nigeria

Correct citation of this article

Adetula, O.A., 2004. Asystasia gangetica (L.) T.Anderson. [Internet] Record from PROTA4U. Grubben, G.J.H. & Denton, O.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands.

Accessed 22 December 2024.