Vernonia (PROSEA Medicinal plants)

Plant Resources of South-East Asia Introduction

List of species

Vernonia Schreber

Protologue: Gen. pl. 2: 541 (1791).

Family: Compositae

Chromosome number: x= 9, 10; V. anthelmintica: 2n= 20, V. cinerea: 2n= 18, V. elaeagnifolia: 2n= 40

Major species

• Vernonia cinerea (L.) Less.,
• V. patula (Dryander) Merr.

Origin and geographic distribution

Vernonia comprises about 1000 species occurring in tropical, subtropical and temperate regions of America, Africa and Asia with its main centre of diversity in the Neotropics. About 35 species occur in the Malesian region, most of which are herbs, shrubs or climbers; only two species are trees.

Uses

All Vernonia species have in common that bitter constituents can be found in almost all plant parts. A multitude of medicinal properties are ascribed to these bitter constituents in particular. Ground leaves or a poultice of leaves of V. cinerea are a remedy for headache and when mixed with a little lime they are also applied to dress wounds. The leaves, either ground or as a decoction, are also used against skin diseases. In Indo-China and the Philippines, a decoction of the root is administered against diarrhoea and stomach-ache. In the Philippines, an infusion of the plant is used in the treatment of cough. In the Moluccas, the root is applied as a cough medicine and the juice of the whole plant to promote parturition. In India the flowers are administered for conjunctivitis and the root is given in cases of dropsy, whereas the seeds are also employed as an anthelmintic and alexipharmic. A decoction of V. patula is used as a general tonic, febrifuge and to treat diarrhoea.

V. anthelmintica (L.) Willd., occurring in India, Burma (Myanmar) and Laos, but not in the Malesian region, is applied as a vermifuge, and has a reputation for curing leprosy and skin diseases. It is also used as insecticide and insect repellent. The seeds, with a high content of epoxy acid, have been traded to Java as "kursani"; in high dosage they are claimed to be an abortivum. V. elaeagnifolia DC., from Burma (Myanmar), northern Thailand and Indo-China, is reported to be used in a mixture with tobacco. The dried and finely chopped wood is smoked in the form of cigarettes to treat ulcerations of the nose. It is also an ingredient of an infusion to relieve cough. V. arborea Buch.-Ham., a common tree of secondary forest, has some medicinal applications as well. An infusion of the root, or a decoction of the bark together with other ingredients, may be given against fever. In southern Sumatra, the bark was chewed at the first signs of sprue.

In Africa, the leaves and roots of V. amygdalina Delile are widely applied in folk medicine. A decoction is taken as a febrifuge and to relieve abdominal pains. In East Africa, the leaves or roots of various Vernonia species, either chewed or as a decoction, are used to cure stomach-ache. Another general application of the leaves, as an infusion or decoction, is in the treatment of coughs, and as a poultice on wounds and sores, either fresh, cooked or pounded.

The young shoots of V. cinerea and V. patula are consumed as a cooked vegetable in Java.

Properties

As with many other Compositae, Vernonia is rich in sesquiterpene lactones. The presence of common compounds such as triterpenes, sterols and flavone glycosides in Old World Vernonia is reported in literature.

The methanol extract of the whole plant of V. cinerea showed significant diuretic activity in rats at doses of 300, 700 and 1000 mg/kg body weight. Activity could be concentrated in the water-soluble fraction of the extract: the freshly prepared water-soluble fraction, representing 300 mg/kg body weight of the dried methanol extract was found to be effective. The effect was not linked to a certain compound or group of compounds; general chemical analysis of this fraction showed the presence of tannins, sugars, flavonoids and glycosides. Furthermore, an aqueous ethanol (50%) extract of the whole plant showed anti-cancer activity against Sarcoma 180 in mice; the maximum tolerated dose was found to be 500 mg/kg body weight.

Vernonin is a triterpenoid isolated from V. cinerea. When injected intravenously in dogs it produces hypotension and an action on the heart comparable to that of digitalin, but in general the compound is much less toxic. Other triterpenes isolated from the roots of V. cinerea are 3β-acetoxy-urs-19-ene and lupeol acetate. When V. cinerea flowers were screened for insecticidal principles, six pyrethrins (pyrethrin I, cinerin I, jasmolin I, pyrethrin II, cinerin II and jasmolin II) were identified by thin layer chromatography.

The anti-inflammatory effect of the alcoholic extract of V. cinerea flowers was tested in adjuvant-induced athritic rats. It was concluded that the extract, administered orally at 100 mg/kg, contained as yet unidentified anti-inflammatory principles. The petroleum ether and chloroform extracts of V. patula showed significant in vitro activity against lymphoid leukaemia L1210 and lymphocytic P388 tumour cell lines. A partially purified fraction was obtained from the chloroform extract, which was significantly active against these tumour cells in in vitro and in vivo models. Preliminary investigations by column chromatography of both petroleum ether and chloroform extract yielded 4 terpenes (2 identified as α-amyrin and its acetate; both inactive in anti-cancer tests) and 1 sterol (β-sitosterol).

Vernolepin, a sesquiterpene dilactone isolated from V. amygdalina, shows platelet anti-aggregating properties. It has a stabilizing effect during freeze-thawing of platelets; it inhibits platelet aggregation induced by arachidonic acid, ADP and collagen, and interferes with ATP release. Electron microscopy shows protection of platelets against adhesion together with a disaggregating effect. All these activities are time-dependent; a steep dose-response relationship is seen. Furthermore, vernolepin has antitumour effects in vitro, just like vernodalin and vernomygdin, two more cytotoxic sesquiterpene lactones isolated from V. amygdalina.

Anti-leishmanial activity of chloroform and methanol extracts of V. amygdalina has been assessed in vitro on Leishmania aethiopica. Amastigotes were more sensitive to V. amygdalina than promastigotes. The chloroform extract had a stronger parasiticidal activity (with median effective doses (ED₅₀) of 18.5 μg/ml for promastigotes and 13.3 μg/ml for amastigotes), than the methanol extract (with ED₅₀ of 74.4 μg/ml and 45.8 μg/ml, respectively). Cytotoxicity caused by V. amygdalina to host cells, the human leukaemia monocyte THP-1 cell line, as determined by the methyl tetrazolium assay, resulted in a median lethal dose (LD₅₀) of 19.6 μg/ml for the chloroform extract and 243.4 μg/ml for the methanol extract. In comparison, the ED₅₀ and LD₅₀ of pentamidine, a standard anti-leishmanial drug, were 0.5 μg/ml and 1.4 μg/ml respectively. These results indicate that V. amygdalina displays potent anti-leishmanial activities and warrants further investigation.

Organic solvent extracts of leaves of V. amygdalina have inhibitory activity for His^- to His⁺ reverse-mutations induced by ethyl methane sulphonate acting on Salmonella typhimurium TA100. The concentrated ethyl acetate, methanol and petroleum ether extracts were heat-stable when dissolved in dimethyl sulphoxide.

Phytochemical investigations of V. anthelmintica revealed the presence of a novel 4α-methylsterol, being 4α-methyl-5α-stigmasta-8,14,24,24'-Z-trien-3β-ol (= 4α-methylvernosterol). The 4-demethylsterol and 4,4-dimethylsterol fractions from the seeds were also investigated. The 4-demethylsterol fraction contained vernosterol and avenasterol as the dominant sterols. 4α-Methylvernosterol is suggested to be the possible intermediate in the biosynthesis of vernosterol in V. anthelmintica seeds.

Clinical tests of the pollen antigens from V. cinerea revealed that they are common allergens causing respiratory tract allergy. The pollen showed allergic manifestations in very low concentrations, were heat stable and non-dialysable, but lost their allergenic property on incubation with trypsin and chymotrypsin.

Adulterations and substitutes

Sesquiterpene lactones of the germacranoline type are also found in Elephantopus, a closely related genus belonging to the tribe Vernonieae.

Description

• Evergreen herbs, shrubs, climbers or rarely small to medium-sized trees up to 30(-40) m tall.
• Leaves arranged spirally, simple, margin entire, glandular below, petiolate, stipules absent.
• Inflorescence terminal or in the upper leaf axils, consisting of widely branched panicles of heads.
• Head with many white, pinkish or purple flowers which are slightly to much longer than the turbinate to campanulate involucre; receptacle alveolate, naked.
• Flowers bisexual, 5-merous, pappus present, corolla tubular with a campanulate to funnel-shaped limb; anthers fused, with sagittate base; ovary inferior, 1-celled and 1-ovulate, style split into 2 stigmas.
• Fruit a faintly to prominently ribbed, cylindrical to many-angled achene; pappus hairs usually 2- or rarely 1-seriate, scabrous.
• Seedling with epigeal germination; cotyledons leafy, glabrous but upper surface glandular dotted, apex truncate to shallowly emarginate; hypocotyl up to 5 mm long, epicotyl very short; first two leaves opposite, subsequent ones alternate.

Growth and development

Light enhances germination of V. cinerea and seeds germinate over a 30-day period at 25°C. Germination decreases gradually from about 60% on the soil surface to less than 10% at 4 cm depth, and seedlings do not emerge from a depth over 1 cm. The pappus on the fruits enhances dispersal by wind and animals.

Other botanical information

The Old World Vernonia species are sometimes placed in the subgenus Orbisvestus, whereas the New World species are placed in the subgenus Vernonia. This subdivision is supported by differences in chromosome numbers and sesquiterpene lactones. Several attempts have been made to refine the genus Vernonia by segregating genera and delimiting sections. However, at present no consensus has been reached by those working on the genus.

Ecology

Vernonia occurs mostly in sunny or slightly shaded habitats, in general corresponding with young secondary vegetation, wasteland and other anthropogenic habitats, from sea-level to 1400 m altitude.

Propagation and planting

Vernonia can be easily propagated by seed.

Diseases and pests

V. cinerea can be the host of tobacco leaf curl virus, powdery mildew (Erysiphe cichoracearum), root-knot nematodes, and cotton bollworm.

Harvesting

When grown as a vegetable, Vernonia is harvested when still young. For medicinal purposes the leaves are picked or the roots are collected.

Genetic resources and breeding

The Vernonia species of medicinal importance have a wide distribution and are common weeds in anthropogenic habitats. Therefore the risk of genetic erosion seems limited.

Prospects

Biological activities of extracts of Vernonia, and their isolated, purified compounds (e.g. the sesquiterpene lactones) show considerable potential in the treatment of e.g. tumours or leishmaniasis. The importance of these indications merits further research. Furthermore, the medicinal Vernonia have potential to be grown as a plantation crop.

Literature

• Akihisa, T., Hayashi, Y., Patterson, G.W., Shimizu, N. & Tamura, T., 1992. 4α-Methylvernosterol and other sterols from Vernonia anthelmintica seeds. Phytochemistry 31(5): 1759-1763.
• Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. 2nd edition. Vol. 2. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. pp. 2266-2268.
• Harborne, J.B. & Williams, C.A., 1977. Vernonieae - chemical review. In: Heywood, V.H., Harborne, J.B. & Turner, B.L. (Editors): The biology and chemistry of Compositae. Vol. 1. Academic Press, London, New York, San Fransisco. pp. 523-537.
• Herrera, C.L., Chanco, G.L. & Sison, F.M., 1980. Chemical and pharmacological studies on Vernonia patula (Dry.) Merr. and Vernonia cinerea (Linn.) Less. In: 4th Asian Symposium on Medicinal Plants and Spices: Abstracts. Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand. p. 249.
• Holm, J., Doll, J. & Holm, E., 1997. World weeds: natural histories and distribution. Wiley, New York, United States. pp. 903-906.
• Isawumi, M.A., 1995. Notes on Vernonia (Vernonieae: Compositae) in West Africa. In: Hind, D.J.N., Jeffrey, C. & Pope, G.V. (Editors): Advances in Compositae systematics. Royal Botanic Gardens, Kew, United Kingdom. pp. 51-106.
• Koster, J.T., 1935. The Compositae of the Malay Archipelago. I. Vernonieae and Eupatorieae. Blumea 1: 351-536.
• Obaseiki-Ebor, E.E., Odukoya, K., Telikepalli, H., Mitscher, L.A. & Shankel, D.M., 1993. Antimutagenic activity of extracts of leaves of four common edible vegetable plants in Nigeria (West Africa). Mutation Research 302(2): 109-117.
• Oliver-Bever, B., 1986. Medicinal plants in tropical West Africa. Cambridge University Press, Cambridge, New York, Melbourne. p. 28.
• Tadesse, A., Gebre-Hiwot, A., Asres, K., Djote, M. & Frommel, D., 1993. The in vitro activity of Vernonia amygdalina on Leishmania aethiopica. Ethiopian Medical Journal 31(3): 183-189.

Selected Sources

• [92] Backer, C.A., 1928-1934. Onkruidflora der Javasche suikerrietgronden. Handboek ten dienste van de suikerriet-cultuur en de rietsuiker-fabricage op Java [Weed flora of Javanese sugar-cane fields. Handbook for the cultivation of sugar-cane and manufacturing of cane-sugar in Java]. Vereeniging het Proefstation voor de Java-Suikerindustrie, Pasuruan, Indonesia. 4 volumes. 970 pp.
• [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.
• [202] Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A-H) pp. 1-1240. Vol. 2 (I-Z) pp. 1241-2444.
• [287] Council of Scientific and Industrial Research, 1948-1976. The wealth of India: a dictionary of Indian raw materials & industrial products. 11 volumes. Publications and Information Directorate, New Delhi, India.
• [458] Gagnepain, F., 1924. Composées [Compositae]. In: Gagnepain, F. (Editor): Flore générale de l'Indo-Chine [General flora of Indo-China]. Vol. 3. Masson & Cie, Paris, France. pp. 448-663.
• [580] Heyne, K., 1950. De nuttige planten van Indonesië [The useful plants of Indonesia]. 3rd Edition. 2 volumes. W. van Hoeve, 's-Gravenhage, the Netherlands/Bandung, Indonesia. 1660 + CCXLI pp.
• [774] Koster, J.T., 1935. The Compositae of the Malay Archipelago. I. Vernonieae and Eupatorieae. Blumea 1: 351-536.
• [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.
• [1128] Pételot, A., 1952-1954. Les plantes médicinales du Cambodge, du Laos et du Vietnam [The medicinal plants of Cambodia, Laos and Vietnam]. 4 volumes. Centre National de Recherches Scientifiques et Techniques, Saigon, Vietnam.

Selection of species

• Vernonia cinerea
• Vernonia patula

Authors

• B. Ibnu Utomo & J.L.C.H. van Valkenburg