Ethnobotanical investigations among tribes in Madurai District of Tamil Nadu (India)

Globally, about 85% of the traditional medicines used for primary healthcare are derived from plants [1]. Traditional medicine and ethnobotanical information play an important role in scientific research, particularly when the literature and field work data have been properly evaluated [2]. India is one of the twelve mega-biodiversity countries of the World having rich vegetation with a wide variety of plants with medicinal value. In many countries, scientific investigations of medicinal plants have been initiated because of their contribution to healthcare. Herbal medicines have good values in treating many diseases including infectious diseases, hypertension, etc. That they can save lives of many, particularly in the developing countries, is undisputable [3].

India possesses a total of 427 tribal communities [4] and over 275 papers have been published on specific ethnic groups [5]. Interest in traditional medicine in India has continuously been increasing; recently, various ethnobotanical studies have been reported to explore the knowledge from the various tribals of Tamil Nadu [6‐13].

Even today many local and indigenous communities in the Asian countries meet their basic needs from the products they manufacture and sell based on their traditional knowledge. Herbal drugs obtained from plants are believed to be much safer; this has been proved in the treatment of various ailments [14]. Rural communities, in particular paliyar tribes, depend on plant resources mainly for herbal medicines, food, forage, construction of dwellings, making household implements, sleeping mats, and for fire and shade. Rural people not only depend on wild plants as sources of food, medicine, fodder and fuel, but have also developed methods of resource management, which may be fundamental to the conservation of some of the world's important habitats [15].

The objective of this study was to assess the richness of ethnomedicinal plant species used by the paliyar tribes in Madurai district forest areas and the traditional medical practices of the people. Similar ethnobotanical studies have been reported in several parts of India to protect the traditional knowledge from disappearing [5, 12, 16‐19]. Documenting the indigenous knowledge through ethnobotanical studies is important for the conservation of biological resources as well as their sustainable utilization.

In Table 1, data obtained from the field survey are presented. In this study 60 plant species belonging to 32 families distributed in 53 genera have been recorded. These contribute to 81 remedies. Many species of the family Acanthaceae and Asclepiadaceae are frequently used (21 remedies from 12 species); the Euphorbiaceae and Solanaceae contribute to 9 remedies from 8 species. The informations collected from this study are in agreement with the previous reports [5‐12], [16‐19].

As seen in Table 1, common health ailments in the study area were skin problems such as wounds, cuts, burns and skin diseases and the largest number of the remedies (16 remedies from 16 species) were used to treat these ailments. Kani tribals in Tirunelveli hills of Tamil Nadu were using 14 plants for the treatment of skin problems [13]; 52 herbal preparations from 31 plants were used for skin diseases by tribals of Uttar Karnataka district, a nearest state of Tamil Nadu [18] and people of Eastern Cape Province, South Africa used 38 plant species for the treatment of wounds [27].

On the other hand, 14 remedies were used to alleviate problems of the respiratory system such as cold, cough, asthma and fever. Among the plants surveyed, Adhatoda zeylanica and Vitex negundo (4 remedies) are used frequently for the preparation of medicines for the treatment of respiratory problems. Respiratory problems are the most encountered illness and there may be hardly any person who has not suffered from respiratory problems in his lifetime [28]. 8 remedies were used against gastrointestinal problems such as stomachache, abdominal pain and ulcer. A previous study (29) has reported the use of 21 medicinal plants from 20 families to treat gastro-intestinal complaints in the same community. 5 remedies were used against inflammatory diseases such as rheumatism, fractured bones and joint pains.

Leaves of Acacia caesia, Asystasia gangetica, Oxalis corniculata, rhizomes of Costus speciosus, Dioscorea opositifolia, fruits of Gmelina arborea, and seeds of Piper nigrum are used as edible plants by the local inhabitants of the study area. The tribal people mostly eat vegetables of leafy varieties, which grow as wild weeds.

There are two types of tribal healers found in the study area namely herbalists and ritualists. Herbalists treat patients only by using plant resources. They diagnose diseases based on the symptoms told by the patients as well as based on their personal experience in treating human ailments. Ritualists believe that specific spirit causes ailments. The whole healing ceremony takes about a day. The preparation of medicines and treatment of diseases connected with the tribal healthcare are accompanied by elaborate rituals and music as previously observed in the case of Mikirs of India [30].

Paliyar tribal practitioners use specific plant parts and specific dosages for the treatment of ailments. The plant products are consumed raw or in the form of a decoction, as infusion for oral treatment and as burnt product, ointments or raw paste when applied externally. The parts of the plant most used for medicinal purposes are leaves, root, stem, fruits, the complete aerial parts, the whole plant, barks (root and stem) and flowers (including the flowering heads) in decreasing order. Internal uses (used in 36 of the cases) are predominating over external (used in 30 cases) uses. Juice (almost mix with water and goat's or cow's milk) and paste are the main methods of preparation, either for oral or for external administration. For topical use, the most important methods used are direct application of the paste or ointment (with oil).

Often, people use more than one plant either separately or mixed together. They mix several plants as ingredients to cure diseases immediately. Generally, fresh part of the plant is used for the preparation of medicine. When fresh plant parts are not available, dried parts are also used. Majority of medicinal plants are used as simple drugs and some plants are used with some other plant parts.

Paliyar tribes use some plants to prepare agricultural implements. For example Terminalia bellirica and Haldenia cordifolia are used to prepare ploughs; they prepare musical instruments from the wood of Gmelina arborea. They crush the fruits of Solanum erianthum and apply topically on their legs, while entering into forest to protect from leech-bite. From this account it is clear that the paliyar tribals like other ancient tribals [31] possess the ability to discern the character of various plants and their beneficial properties. It is interesting to note that such a way of life, particularly with respect to healthcare practices has hardly undergone any change even in the present day.

This study shows that knowledge and usage of herbal medicine for the treatment of various ailments among paliyar tribes is still a major part of their life and culture. They use forest plants, weeds, fruit plants, vegetables, spices, ornamental plants, ferns and many others as traditional medicine. Although many of these species are known as medicinal plants, others are mainly used for nonmedicinal purposes such as preparing agricultural implements. Adhatoda zeylanica, Vitex negundo, Plectranthus coleoides, and Piper nigrum are the leading species used as remedies against a variety of complaints.

The data collected show that majority of the remedies are taken orally. Most of the reported preparations are drawn from a single plant; mixtures are used rarely. In other parts of the country, the use of mixtures of plant species in treating a particular ailment is fairly common [6‐13]. Generally, the people of the study area still have a strong belief in the efficacy and success of herbal medicine. The results of the present study provide evidence that medicinal plants continue to play an important role in the healthcare system of this tribal community.