Ethnobotany of medicinal plants used by tribes of Kerala

Abstract

Investigations were carried out on the Ethnobotany of medicinal plants of the tribes of Kerala in the Centre for Advanced Studies on Humid Tropical Tree Crops and Environmental Horticulture attached to College of Horticulture, Vellanikkara during 1988 – 1991. The study included documentation of ethnomedicines, botanical description and propagation of selected five rare plants and screening of selected plants for antimicrobial activity. The Malayan tribe of the selected localities, viz., Chimminy, Marottichal, Sholayar, Vazhachal and Vazhani were selected for the study. Ethnomedico – botanic information on 212 plant species, belonging to 184 genera of 73 families were documented. According to the magnitude of availability of information and paints, the localities could be ranked as Sholayar > Vazhachal > Marottichal > Chimminy/ Vazhani. Erosion of the knowledge and depletion of the flora as urbanization advances were observed. The tribe knew the remedy for almost all the common diseases. Single plant remedies were observed for alopecia (Nyctanthes arbortristis), bone fracture (Justicia gendarussa), paralysis (Cassia fistula), prolapse of the rectum (Mangifera indica), whitlow (Euphorbia antiquorum) and as analgesic (Thevetia neriifolia), antilactogenic (Jasminum pubescens) and diaphoretic (Oroxylum indicum). Maximum number of plants, either alone or in combination were used for eye diseases followed by diarrhoea and dysentery, loss of hair and snake bite. Plants used as animal and insect repellents and for cattle diseases were also documented. Information was also obtained on diagnostic and prophylactic plants. Use of Allium sativum along with Ocimum sanctum as a prophylactic for mumps, Allanthus excels for lalarial fever, and the leaves of Tragia involucrate for diagnosing pregnancy were very simple and worth mentioning. Plants were used in combination with other plants ; plant products like oils, jiggery, sugar, animals like chiken, crab and tadpole; animal products like butter, honey and milk; and inert materials like ash, clay and salt. Religious or magical rituals accompany the uses of certain plants. They also keep certain taboos about medicinal plants. Five rare plants, Alstonia venenata, Coscinium fenestratum, Habenaria latilabris, Rotula aquatic and woodfordia fruticosa were botanically described and illustrated. Feasibility of multiplication of these species under Vellanikkara conditions revealed that the easiest method of multiplication was through root cuttings in Coscinium fenestratum, pseudobulbs in Habenaria latilabris, hardwood cuttings in Rotula aquatic and seeds in Woodfordia fruticosa. In Alstonia venenata, the treatments tried were not successful. None of the ether and alcoholic plant extracts screened showed any antimicrobial properties while the essential oils from four plants showed remarkable traits in this aspect. Clove leaf oil was found to be inhibitory to all the bacteria and fungi tested . The inhibition was more compared to most of the antibiotics and fungicides available in the market. The essential oil of Coscinium fenestratum and Cinnamomum verum also showed fairly good antibacterial and antifungal properties. The essential oil of Alstonia venenata was able to suppress the growth of bacteria, though ineffective in the case of fungi. However, further in vivo studies are required in order to prove its efficacy in natural/experimental infections before its utility is advocated for field conditions. The information gathered revealed that the tribal community of Thrissur District has a traditionally self managed system of folk medicine. Comprehensive and systematic surveys and documentation are required in other unexploited areas also for gathering such valuable information before they are being lost.