Cerbera (PROSEA Medicinal plants)
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Introduction |
Cerbera L.
- Protologue: Sp. pl. 1: 208 (1753); Gen. pl. ed. 5: 98 (1754).
- Family: Apocynaceae
- Chromosome number: x= 20; C. manghas: 2n= 40, C. odollam: 2n= 40
Major species
- Cerbera manghas L.,
- C. odollam Gaertner.
Vernacular names
- Grey milkwood (En, trade name)
- Indonesia: bintaro (Java)
- Malaysia: pongpong (Peninsular)
- Papua New Guinea: cerbera (general).
- Burma (Myanmar): kalwa
- Cambodia: krapur
- Thailand: teenpet (central)
- Vietnam: mướp xát, mật sát.
Origin and geographic distribution
Cerbera comprises 6 species and is found from Tanzania (Pemba), Madagascar and islands in the Indian Ocean to India, Burma (Myanmar), Indo-China, Taiwan, southern Japan and Thailand, throughout the Malesian region towards Melanesia and north-eastern Australia.
Uses
Several Cerbera species are applied medicinally against itch and sores. C. manghas and C. odollam are well known for their poisonous seeds, which are for various purposes in the Philippines and Thailand including for stupefying fish. In areas where both species occur, they are apparently used indiscriminately. An excellent purgative can also be prepared from their root and bark. The seeds contain an oil which has been used for making candles. In Thailand, the bark is used as a laxative, antipyretic and in the treatment of dysuria. The wood is used in paralysis, and the outer bark in the treatment of ringworm. The leaves are also externally applied to treat ringworm. The oil from the seeds is externally used to treat scabies and as a hair tonic. The flowers are applied to treat haemorrhoids. In Vietnam, a liniment of the seed oil is used to treat scabies and itch, and applied to the hair to kill head lice. The bark and leaves are occasionally used with caution as a purgative. In the Solomon Islands, heated leaves of C. floribunda K. Schum. are rubbed on the skin to relieve aches and sores. Likewise the exudate is placed on sores. In New Ireland, Papua New Guinea, the scraped bark mixed with leaves of wild ginger is squeezed into water and taken as a remedy for malaria, black water fever and hepatitis.
C. manghas and C. odollam are also planted as ornamentals. The wood of Cerbera is used for non-durable or indoor applications. The wood of both C. manghas and C. odollam yields a good charcoal.
Production and international trade
Cerbera is only locally used medicinally and is not traded on the international market.
Properties
Both Cerbera species are known to contain a series of cardiac glycosides of the cardenolide type. The seeds contain cardenolides derived from the aglycones tanghinigenin and digitoxigenin, such as cerberin, neriifolin, thevetin B and 2'-O-acetyl-thevetin B. The principal cardenolides contained in the bark and root are gentiobiosyl-thevetoside and glucosyl thevetoside along with other thevetosides derived from tanghinigenin and 17βH-tanghinigenin as their aglycone. Cardenolides in the leaves are: 17βH-neriifolin, neriifolin, 17βH-deacetyltanghinin and deacetyltanghinin.
Besides the cardiac glycosides, phytochemical investigations of both species revealed the presence of a series of lignans, derived from olivil (the cerberalignans D-I, from the stems), and the monoterpenoids cerberidol, epoxycerberidol and cyclocerberidol together with their respective D-allopyranosides.
The purified cardenolide cerberin acts on plain muscle preparations as definite stimulant both with regard to its tone and peristaltic movements. As such it behaves as a parasympatomimetic poison. When administered subcutaneously to animals in dilute solutions it produces vomiting, diarrhoea and sometimes unconsciousness.
In moderate doses cerberin has positive inotropic properties. It acts both on the rhythm and amplitude of the heart. In toxic doses, it produces a negative inotropic and chronotropic effect. This is in correspondence with the administration of graded doses of an alcoholic extract of the seeds in anaesthetized cats and dogs, which resulted in first degree heart block, atrial and ventricular fibrillation and death. Furthermore, the immediate and delayed toxicity of C. odollam leaf extract was studied in mice. The leaves appeared to be relatively devoid of the marked toxicity found in seeds. At doses smaller than the maximal dose was never lethal (14.5 g/kg intra peritoneally), the leaf extract decreased spontaneous motor activity in mice significantly, increased the reaction time to a thermal stimulus, reduced the duration of pentylenetetrazole-induced tonic seizures and mortality, and potentiated sodium pentobarbital-generated hypnotic effects.
Other pharmacological effects of Cerbera extract include activity in a DPPH free radical scavenging assay; the lignans olivil, (-)-carinol, and (+)-cycloolivil were identified as active principles. In addition, ethanolic extracts of C. manghas have shown selective activity against vesicular stomatis viruses (VSV) at a minimum inhibitory concentration (MIC) of 0.005-0.1 mg/ml and cytotoxic activity was observed in HeLa cells at a median curative dose (CD50) of 0.001-0.1 mg/ml.
Cerbera yields a lightweight to medium-weight timber. Shrinkage upon seasoning is moderate; the wood seasons readily and well. It works easily. The wood is non-durable and resistant to preservative treatment under pressure.
Adulterations and substitutes
Cardiac glycosides are present in several other genera of the Apocynaceae family, e.g. Thevetia (structurally very similar to Cerbera) and Strophanthus.
Description
- Evergreen shrubs or small to medium-sized trees up to 30 m tall; bole up to 90 cm in diameter, not buttressed; bark surface irregularly scaly or warty, peeling off in small flakes, exuding abundant white latex.
- Leaves arranged spirally, clustered at the apices of twigs, glabrous, entire or sinuate with a decurrent base.
- Inflorescence terminal, cymose, glabrous.
- Flowers actinomorphic, 5-merous; calyx deeply divided or the sepals free; corolla hypocrateriform, white or light red, strongly scented, lobes overlapping to the left in bud; disk absent; anthers lanceolate, contiguous to the style head and with filiform appendages; carpels 2, free, with 4 ovules in each carpel, style-head composed of 2 annular swellings, surmounted by 2 thick appendages.
- Fruit consisting of 2 (or by abortion 1) drupaceous mericarps, exocarp fleshy, endocarp woody, seeds 1 or 2.
- Seed compressed, not winged.
- Seedling with hypogeal germination; hypocotyl not elongated.
Growth and development
C. manghas develops according to Koriba's architectural tree model, characterized by orthotropic axes which branch to produce initially equivalent modules, but where one of these subsequently becomes dominant, constituting one unit of the sympodial trunk. In Vietnam, Cerbera spp. flower from February to October and bear ripe fruits from August to April. In Australia C. manghas flowers and fruits throughout the year. The flowers are pollinated by insects. The fruits of C. manghas and C. odollam are dispersed by water and are quite commonly washed up on the shores.
Other botanical information
There used to be considerable confusion about the correct names for C. manghas and C. odollam. As a result, it is often not possible to allot given information to one of these species. Furthermore, open flowers, or else mature or almost mature buds are indispensable for determination. Fruiting specimens can only exceptionally be named, often only on the basis of mutual exclusion by the natural distribution of the species involved.
Ecology
Cerbera species are generally associated with water and occur along rivers or streams, in swamp forest and behind mangroves, but may also be found in shrubby savanna or in secondary forest edges. Some species, like C. manghas and C. odollam, are common elements of mangrove swamps and tidal river banks and may root in muddy locations but also in sandy coastal soils. Most Cerbera species occur at low altitude in primary lowland rain forest, but some may ascend up to 2000 m. Where species distributions overlap, they have different biotopes.
Propagation and planting
Cerbera is usually propagated by seed but can also be propagated by ripewood cuttings. Cerbera should preferably be grown in full light in a fertile moist but well-drained loam with additional leaf mould.
Harvesting
Fruits of Cerbera are harvested when ripe.
Handling after harvest
The pulp of the ripe fruits of Cerbera is removed to obtain the seeds. Alternatively, the fruits are dried first, and then cracked to liberate the seeds. Seeds are pressed to extract the oil.
Genetic resources and breeding
The Cerbera species of medicinal importance have a widespread natural distribution. They are locally common and sometimes planted. The risk of genetic erosion seems therefore rather limited.
Prospects
At present in medicine, cardiac glycosides are only applied in specific cases. The drug of choice is generally digoxin from Digitalis lanatae Ehrh. or in acute situations the strophanthins (e.g. ouabain) from Strophanthus. Therefore the cardenolides from Cerbera are unlikely to play an important role in future medicine; in certain cases they may, however, be of some local importance.
Literature
- Ali, A.M., Mackeen, M.M., El-Sharkawy, S.H., Hamid, J.A., Ismail, N.H., Ahmad, F.B.H. & Lajis, N.H., 1996. Antiviral and cytotoxic activities of some plants used in Malaysian indigenous medicine. Pertanika 19(2-3): 129-136.
- Cambie, R.C. & Ash, J., 1994. Fijian medicinal plants. Commonwealth Scientific and Indutrial Research Organisation, Canberra, Australia. pp. 82-83.
- Hien, T.T., Navarro-Delmasure, C. & Vy, T., 1991. Toxicity and effects on the central nervous system of a Cerbera odollam leaf extract. Journal of Ethnopharmacology 34(2-3): 201-206.
- Lee, S.K., Mbwambo, Z.H., Chung, H., Luyengi, L., Gamez, E.J., Mehta, R.G., Kinghorn, A.D. & Pezzuto, J.M., 1998. Evaluation of the antioxidant potential of natural products. Combinatorial Chemistry and High Throughput Screening 1(1): 35-46.
- Leeuwenberg, A.J.M., 1999. Series of revisions of Apocynaceae XLVII. The genus Cerbera L. Wageningen Agricultural University Papers 98.3. 64 pp.
- Nguyen Van Duong, 1993. Medicinal plants of Vietnam, Cambodia and Laos. Mekong Printing, Santa Ana, California, United States. pp. 57-58.
Selection of species
Authors
- Tran Cong Khanh
