Aerva (PROSEA)
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Introduction |
Aerva Forssk.
- Protologue: Fl. aegypt.-arab.: 170, cxxii (1775).
- Family: Amaranthaceae
- Chromosome number: x= unknown; A. lanata: 2n= 16, A. sanguinolenta: 2n= 36, 42, 44, 52
Major species
- Aerva lanata (L.) A.L. Juss. ex Schultes,
- A. sanguinolenta (L.) Blume.
Origin and geographic distribution
Aerva consists of approximately 10 species and occurs in tropical and subtropical regions of Africa and Asia. Africa is considered the centre of diversity. Two species occur within the Malesian region, especially in regions with a monsoon climate.
Uses
Common medicinal uses of Aerva include applications as diuretic (valued in cases of lithiasis and catarrh of the bladder, and for prostatic ailments) and as vermifuge. In India the dried plants are used against diabetes and malaria. The seeds are used against bronchitis. In Sri Lanka small clumps of A. lanata are frequently grown in gardens to make a medicinal tea. The use of cultivated reddish forms of A. sanguinolenta to treat haematuria and menstruation problems has been considered as doctrine of the signature. In India the leaves are made into a paste and applied for the treatment of wounds. A. sanguinolenta is also cultivated as an ornamental.
Production and international trade
Aerva is usually cultivated in home gardens for use in local medicine and as an ornamental, and the plants do not enter the international trade.
Properties
Several alkaloids have been isolated, including aervine, methylaervine, aervoside, aervolanine, canthine-6-one and β-carboline-1-propionic acid in A. lanata. Several flavonoid glycosides have also been isolated and identified from this species, e.g. narcissin, aervitrin and 4 flavonoid β-coumaroylglycosides, together with 2 feruloylamides and other phenolic compounds. The compounds β-sitosterol, campesterol and chrysin have been isolated from A. lanata plants cultivated in Egypt and β-sitosterol, daucosterol, syringic acid, vanillic acid, feruloyltyramine and feruloylhomovanillylamine have been isolated from plants cultivated in Russia. Glucose, galactose and xylose were the predominant carbohydrates in hydrolysates from leaves and flowers.
Preliminary tests in India on rats to study the effects of fresh juice and aqueous extracts of A. lanata on the chemically induced nephrotic syndrome, and as anti-inflammatory, diuretic and steroidal agent showed positive results. An ethylacetate extract of the dried whole plant exhibited antimalarial activity. The diuretic effect has also been studied in humans. An extract (200 ml of a 50 g/l infusion) was reported to induce diuresis; the urine output was significantly elevated with extract from fresh plants, when compared with the control group which received the same quantities of water or isotonic saline. Furthermore, of the different parts of the plants tested, the flowers were found to be most effective in inducing diuresis. However, the nature of the diuresis (aquaretic or saluretic) was not defined, since only the urine flow was estimated. In a more comprehensive double-blind setting with healthy volunteers these results could not be repeated: the A. lanata extract did not significantly increase urine flow, sodium excretion, potassium excretion, or urine and plasma osmolality as compared to water or a diluted infusion of tea prepared to resemble the A. lanata extract as closely as possible in colour and taste. The influence on the formation of urinary (bladder) stones was investigated in the rat. It was shown that A. lanata did not affect the formation or dissolution of urinary stones of the phosphate type.
Leaves of A. sanguinolenta contain a potent inhibitor of plant virus infection. Leaf extracts mixed with the virus inoculum of tobacco mosaic virus and sunhamp rosette virus caused almost total inhibition of virus infectivity. The resistance to virus infection induced by the extract is systemic and long lasting. Leaf extracts of A. sanguinolenta, applied as 4% foliar spray, delayed the appearance of disease symptoms caused by yellow mosaic virus on mung bean, but they could not be used to control the disease.
Adulterations and substitutes
Java tea (Orthosiphon aristatus (Blume) Miq.) is another herb which is reputed for its diuretic activity, and which is prescribed to treat similar complaints and in similar preparations.
Description
- Perennial, erect or somewhat clambering, dioecious or polygamous herbs up to 200 cm tall, often almost woody at base, often divided from near the base into ascending or erect branches; branches often unbranched for a considerable length, terete, densely clothed with appressed or patent whitish hairs.
- Leaves alternate or opposite (often on a single specimen), simple and entire, densely clothed with appressed white hairs on both surfaces (but especially beneath); petiole short, stipules absent.
- Inflorescence an axillary and terminal spike, solitary or fascicled and sometimes forming a paniculate inflorescence.
- Flowers small, usually bisexual but sometimes unisexual, solitary in the axil of persistent bracts, subtended by 2 bracteoles, white or tinged with purple; tepals 5, free, hairy; stamens 5, filaments connate at base, free parts subulate, about half as long as tepals, alternating with shorter staminodes, anthers 2-celled; ovary superior, 1-celled, compressed, glabrous, style very short with 1-2 stigmas.
- Fruit a much compressed utricle, about 1 mm in diameter, bursting irregularly, 1-seeded.
- Seed reniform, shiny black.
Growth and development
A. lanata is often reported not to flower before the second year, but flowering sometimes does occur in the first year. In India two forms have been distinguished, one reddish with a deep penetrating taproot having numerous lateral roots, short branches and leaves and comparatively long and numerous spikes, and the other green in colour with a short, thin taproot having few lateral roots, longer branches, larger leaves and comparatively short and few spikes. The first form is apparently an adaptation to drier conditions. Intermediate forms have been found.
Other botanical information
Three Aerva species have been reported to occur in the Malesian area, but one of these (A. curtisii Oliv.) has been transferred to a new genus Psilotrichopsis together with the continental South-East Asian species A. cochinchinensis Gagn.
Ecology
Both Aerva species occur especially in periodically dry areas and in dry locations. They are found in sunny or slightly shaded sites, e.g. along roadsides, in waste places, in brushwood and hedges, and are common in many regions. They can be a weed on cropped land.
Propagation and planting
A. sanguinolenta may be propagated by stem cuttings. Plant growth regulators (e.g. ethyl hydrogen-1-propyl phosphonate) promote root formation and subsequent shoot growth.
Genetic resources and breeding
Aerva species occur widespread in anthropogenic habitats and are not at risk from genetic erosion.
Prospects
Aerva may have some prospects as a medicinal plant that is easy to cultivate on a small scale e.g. in home gardens. The diuretic properties that have been claimed since antiquity, however, should be clarified first to define their exact nature, before recommendations can be given for a possible application of A. lanata as a drug.
Literature
- Amin, K.M.Y., Ahmed, S. & Khan, N.A., 1994. Anti-nephrotic syndrome ethnic drug Bishiri Booti (Aerva lanata) - experimental study of relevant pharmacological actions. Ethnobiology in human welfare: abstracts of the fourth international congress of ethnobiology, Lucknow, Uttar Pradesh, India, 17-21 November, 1994. p. 94.
- Backer, C.A., 1949. Amaranthaceae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Series 1, Vol. 4. Noordhoff-Kolff N.V., Djakarta, Indonesia. pp. 84-86.
- de Padua, L.S., Lugod, G.C. & Pancho, J.V., 1981. Handbook on Philippine medicinal plants. Vol. 3. Technical Bulletin Vol. V, No 2. Documentation and Information Section, Office of the Director of Research, University of the Philippines at Los Baños, the Philippines. p. 5.
- Nirmala Mary, T. & Aruna Prabha, S., 1980. Ecology of Aerva lanata Juss. Geobios 7(6): 285-286.
- Pervykh, L.N., Karasartov, B.S. & Zapesochnaya, G.G., 1992. A study of the herb Aerva lanata IV. Flavonoid glycosides. Chemistry of Natural Compounds 28(5): 509-510.
- Singh, S.S., 1992. Rooting and regeneration potential of stem cuttings of Aerva sanguinolenta L. as influenced by ethyl hydrogen-1-propyl phosphonate (Niagara). Acta Botanica Indica 20(2): 294-296.
- Udupihille, M. & Jiffry, M.T.M., 1986. Diuretic effect of Aerva lanata with water normal saline and coriander as controls. Indian Journal of Physiology and Pharmacology 30(1): 91-97.
- Verma, H.N. & Srivastava, A., 1985. A potent systematic inhibitor of plant virus infection from Aerva sanguinolenta Blume. Current Science (Bangalore) 54(11): 526-528.
- Zapesochnaya, G.G., Kurkin, V.A., Okhanov, V.V. & Miroshnikov, A.I., 1992. Canthin-6-one and β-carboline alkaloids from Aerva lanata. Planta Medica 58(2): 192-196.
- Zapesochnaya, G.G., Pervykh, L.N. & Kurkin, V.A., 1991. A study of the herb Aerva lanata. Chemistry of Natural Compounds 27(3): 336-340.
Selection of species
Authors
N. Bunyapraphatsara & R.H.M.J. Lemmens
