Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi

This is the final version of the article. Available from Springer Nature via the DOI in this record.Animals self-medicate using a variety of plant and arthropod secondary metabolites by either ingesting them or anointing them to their fur or skin apparently to repel ectoparasites and treat skin diseases. In this respect, much attention has been focused on primates. Direct evidence for self-medication among the great apes has been limited to Africa. Here we document self-medication in the only Asian great ape, orang-utans (Pongo pygmaeus), and for the first time, to our knowledge, the external application of an anti-inflammatory agent in animals. The use of leaf extracts from Dracaena cantleyi by orang-utan has been observed on several occasions; rubbing a foamy mixture of saliva and leaf onto specific parts of the body. Interestingly, the local indigenous human population also use a poultice of these leaves for the relief of body pains. We present pharmacological analyses of the leaf extracts from this species, showing that they inhibit TNFα-induced inflammatory cytokine production (E-selectin, ICAM-1, VCAM-1 and IL-6). This validates the topical anti-inflammatory properties of this plant and provides a possible function for its use by orang-utans. This is the first evidence for the deliberate external application of substances with demonstrated bioactive potential for self-medication in great apes.We thank our financial supporters: the Wildlife Conservation Society, the U.S. Fish and Wildlife Service Great Apes Conservation Fund, Primate Conservation Inc., Foundation UMI – Saving of Pongidae, the L.S.B. Leakey Foundation, NERC (Natural Environmental Research Council) and the University of Exeter. L.R. and K.D. were supported by the Ministry of Education Youth and Sports, Czech Republic (grant LO1204 from the National Program of Sustainability and Agricultural Research). We are also very grateful to grant No. P505/11/1163 from The Grant Agency of The Czech Republic and to Prof. Jitka Ulrichová for the kind gift of HUVEC cells