The medical ethnobotany of India is the study of Indian medicinal plants and their traditional uses. Plants have been used in the Indian subcontinent for treatment of disease and health maintenance for thousands of years, and remain important staples of health and folk medicine for millions. Indians today utilize plants for both primary medical care (principally in Rural and undeserved areas) and as supplementary treatment alongside modern medical science. It is estimated that 70% of rural Indians use traditional plant based remedies for primary healthcare needs. This reliance of plants for medicine is consistent with trends widely observed in the developing world, where between 65% and 80% of people use medicinal plant remedies.
Herbal medicine in India is largely guided by folk medicine, both in codified cultural practices shared widely (Ayurveda, Siddha, Unani), and highly localized practices unique to individual tribes or tribal groups (Adivasi). Between 3,000 and 5,000 species of medicinal plants grow in India with roughly 1,000 threatened with extinction. Of these, more than 2,400 plant species have been documented for medicinal use.
Herbal Ayurveda Ayurveda practitioners believe certain plants can restore balance distorted by disease. The vast majority (90%) of Ayurvedic remedies are plant based.
Although firmly rooted in folk medicine, Ayurvedic herbal remedies have been evaluated by laboratory and clinical studies to evaluate treatment efficacy. Some plants used in Ayurveda have biologically active secondary metabolites with potential value. Other remedies do not have established therapeutic value, and some may have deleterious health effects.
At least 700 plants have been identified from Ayurvedic medicinal systems. Although more than 12,000 Sanskrit plant names have been identified in classical Ayurvedic texts (including samhitas and nighantus) there is great difficulty in establishing exact botanical identities of many referenced species. Plants are prepared according to tradition, utilizing specific plant parts as indicated in historical texts. Ayurvedic belief stipulates that certain plant parts (e.g. leaf, flower, root) have specific properties key to treating disease.
Plant properties in Ayurveda Ayurvedic medicine is guided by a complex set of cultural, religious, and textual practices. Despite diversity in its application and practice, it operates as a codified system of folk medicine with a coherent methodology. Broadly speaking, Ayurvedic practitioners evaluate plants for medical use by examining 5 purported physical and energetic properties:
Rasa - taste or "essence"- broadly categorized into sweet (madhura), sour (amla), salty (lavana), pungent (kaṭu), bitter (tikta) or astringent (kaṣaya). Vīrya - effect on metabolism or body temperature Vipāka - effects on digestion Prabhāva - unique properties inherent to the plant Karma - therapeutic action (e.g. digestive, stimulant, purgative)
Herbal Preparations in Ayurveda
Processing herbs Ayurvedic practitioners process plants with the goal of enhancing absorption. Shelf life and ease of production are additional concerns in herbal preparations. Some common herbal preparations include herbal paste (kalka), powder (curna), decoction (kasaya), teas (phanta), jams (paka), medicated wines (arista), pills (vati), and herbal oils (taila).
Mixed herbal remedies and synergism Ayurvedic treatments are usually mixtures of multiple herbs (polyherbal formulations). Ayurvedic practitioners believe that certain herbs, when combined, have complementary effects which can enhance treatment efficacy; This concept is called synergism. The Ayurvedic text Sarangdhar Samhita (c. 1300 AD) emphasizes the importance of synergism. One common Ayurvedic remedy (trikatu) is prepared by combining ginger, long pepper, and black pepper as an aid for digestion or gastric distress. Ayurvedic practitioners believe that such combinations can enhance absorption. A 2014 review proposed several mechanisms that may be the basis for therapeutic herbal synergism.
Safety and Medical Efficacy
Ayurvedic medicine and drug interactions Herbal preparations in Ayurveda can impact the absorption (or bioavailability) of pharmaceuticals. Because Ayurveda is often used by practitioners to supplement conventional modern medicine, the interactive effects of Ayurvedic treatments can medically significant. For instance, medicinal plant remedies can interfere with the cytochrome enzyme system (CYP), a network of liver enzymes extremely important in drug metabolism. Inhibiting or potentiating CYP enzymes is the most common adverse effect of herbal remedies on medication absorption. Potentiation of CYP can cause medication activity to drop low beyond the point of therapeutic effect, while inhibition of the CYP system can cause medication levels to spike dangerously high.
Some Ayurvedic medicinal plants (Silybum marianum, Cannabis spp.) are CYP3A4 inhibitors. A commonly used antifungal medication, ketoconazole, is processed by the CYP3A4 enzyme. Use of this ketoconazole with any CYP3A4 inhibitor is potentially dangerous and a cause for medical concern. There are countless other herb-pharmaceutical interactions with potentially serious effects.
Responsible Ayurvedic practitioners must take into account how herbal medications can interact with other drugs, or even other concurrent consumed herbals.
Quality control While some preparations may be of high quality, many herbal medicines and supplements are not subject to rigorous quality control. Herbal concoctions may contain little-to-nothing of the herb advertised, or may even be contaminated with heavy metals or other toxic substances. This is not an issue relegated to Ayurvedic practice, but is a global phenomenon, even in developed countries.
Recognizing the key importance of herbal medications to healthcare in the developing world, the World Health Organization (WHO) has proposed quality control mechanisms for marketed medicinal plant medicines, including Ayurveda. This includes DNA barcoding to ensure contents of herbal preparations match advertised/labelled species. An important milestone was reached in 2019, when 65% of WHO member states had a documented registration system for herbal medicines, a significant improvement over the previous two decades.
Research into efficacy In 2021, a systemic review into Ayurvedic treatments for sinusitis determined the necessity of further rigorous clinical studies before conclusions about safety and efficacy could be reached. A major challenge in assessing Ayurvedic herbal medicines is substantial variation in quality between remedies. Multiple reviews on Ayurveda determined that standardization of quality and herbal contents is required for research. This includes research into herbal contents, therapeutic efficacy, chemical profiling of medicines, and identification of actual therapeutic modes of action (i.e., how the medicines actually work).
Another review found that Ayurvedic herbs could be the basis for research into neuroprotective compounds.
Ethnobotany by region India is home to speakers of between 453 and 780 languages with many different cultures and subcultures present across 28 states and 8 union territories. This diversity is reflected in complex regional variation in the usage of herbal medicines. While Ayurveda and other elements of folk medicine are practiced nationally, the tribal peoples of India (Adivasi) have uses for medicinal plants unique to themselves or their geographic locale.
At least 50 million people belong to Adivasi communities, constituting at least 427 tribal groups (with some much higher estimates). Much of the regional variation in plant use can be attributed to the ethnobotany practiced by Adivasis in rural India. Local variations in climate, ecology, and culture determine the availability and use of medicinal plant species.
Eastern Ghats Range
The Eastern Ghat Mountain range begins in the state of Odisha, traveling south through Andhra Pradesh and Telangana, terminating finally in Tamil Nadu. The Eastern Ghats, and the accompanying western portion of the central Deccan plateau, are characterized by a tropical savanna climate. Severe dry seasons allow for a landscape dominated by grasslands with sparse trees (savanna ecosystem) or tropical deciduous forests.
These mountains have been home to many tribal peoples since ancient times. In 2017, over 200 tribes were reported in the regions of the Eastern Ghats and Deccan plateau. A summary of ethnobotanical surveys identified 1,800 species of medicinal plants occurring in these regions of India, with 782 species actually used. Medicinal plants are used in codified indigenous healthcare practices, such as Ayurveda, as well as local practices unique to tribes or tribal groupings. Of the ethnic or tribal groups in this region, 54 are reported to utilize plants for their primary medical needs, though only 40 have been surveyed for exact plant species used.
Medicinal plant taxonomy The 782 medicinal plants used in this region belong to 132 families. Overwhelmingly, identified plants belonged to the legume, dogbane, orchid, nightshade, and coffee families. Legumes (Fabaceae), the largest single family, accounted for 67 species. The most prolific genera were Cassia (Fabaceae) and Solanum (Solanaceae), each containing 11 species. By plant habit, utilized plants were herbs (41%), trees (24%), shrubs (22%) and lianas/vines (13%).
75 species of plants used for medicine in the region are unique to the Eastern Ghats.
Local plants and their uses Of 782 utilized plants, only 28 species were used by all assessed tribal communities. Plant species were most frequently utilized for issues relating to the stomach and skin disease, with 120 species being used as primary treatments in either of these problem categories.
Abrus precatorius was the medicinal plant most widely cited in ethnobotanical surveys of the region. Although parts of the plant are extremely toxic and hazardous when ingested, leaves of this species are utilized for treatment of bronchitis, eczema, hepatitis, skin disease, gynecological disease and in treatment of venomous snake bites. Aegle marmelos, or Bael, is a tree with religious significance utilized for treatment of gastrointestinal and skin disease. Although used throughout India as a treatment for jaundice, the plant creat (Hindi: kaalmegha) (Andrographis paniculata) is used in the Eastern Ghats as an anti-malarial.
Tribal communities in this region are noted for the reverence paid to trees in religious practice.
Western Ghats and West Coast
The Western Ghat Mountain range begins in the southeastern corner of Gujarat, traversing the states of Maharashtra, Goa, Karnataka, and Kerala. The western portion of these mountains, and the accompanying coastal regions, receive among the highest annual rainfalls of any part of India.The Malabar coast (from Goa to the southernmost part of peninsular India) receives over 250 cm of rain annually. These areas are characterized by a tropical monsoon/tropical wet climate. Coastal areas and much of the mountain slopes contain tropical evergreen and moist deciduous forests, with rain forests in Kerala.
Because of the rain shadow effect, eastern slopes of the Western Ghats and the accompanying portions of the Deccan Plateau are very dry, receiving <40 cm a year. This dry area, affecting eastern Gujarat, Maharasthra, and Karnataka, is classified as semi-arid steppe climate. These areas qualify as tropical thorny woodland and dry deciduous forest.
The Western Ghats region is a global biodiversity hotspot, with more than 1500 endemic plant species. Though only 5% of India's landmass, the region contains about a third of India's plant species. As many as 35% of plant species here are endemic.