Medicinal Plants in the Diet of Golden Langur Trachypithecus geei in Kakoijana Reserve Forest, Western Assam, India. A Bio-Rational for the Search of New Medicines for Human Use?

The present study expected to compare the plant food diet of Golden Langur (Trachypithecus geei) inhabiting in Kakoijana Reserve Forest of Western Assam with medicinal plant species used by humans in the surrounding areas of the park as vegetables with medicinal properties. The diet of Golden Langur was studied by direct observation and Scan sampling method along with the plants used as medicine and food by the local tribes, India from March 2013 to April 2015. A group of 9 Golden Langurs of different age and sex classes was observed to feed on 152 different plant species belonging to 55 families. Among the different plant categories, trees accounts for 76%, followed by climber and shrub each 10%, grass 2%, fern and orchid each being 1% and liana 0.7% .The highest percent of food tree species belonged to the family Moraceae (9%) followed by Fabaceae (7%) and Euphorbiaceae (5%). The Langurs primarily fed on young leaves, mature leaves, fruits, seeds, figs, tubers and flowers during the study period. Semi structured interviews showed that 45 plant species used by locals as medicines, 17 species used as vegetables and two are rare medicinal plants of Assam. The diet species of Golden Langur was compared with other areas and discussed. The similarities between the ingestion of plants by primates and their medicinal use by humans provide a bio-rational for the search of bioactive plants in primate diet.