Chimpanzee-Guided Discovery of a Non-Native Bioactive Plant

Studies on chimpanzees suggest that some plants are consumed for their biological properties. Low frequency of consumption, small ingested quantities, complex food processing for a low nutritional value, and local ecological knowledge from human populations can serve as useful indicators for detecting self-medicative behavior. Since 2008, wild chimpanzees have been monitored in Sebitoli, Kibale National Park, Uganda. This study focuses on a plant locally called "Angel's trumpet," selectively consumed by chimpanzees but previously botanically unidentified. Across 890 observation days, 25 consumption events were recorded involving 18 chimpanzees, each ingesting about 10 g of pith. The plant was botanically identified as Acnistus arborescens, a species native to Central and South America and not previously reported in Africa. The plant is known to contain withanolides particularly studied in mice and humans for their anxiolytic effects. Chemical analysis of leaves and pith conducted during this survey revealed diverse withanolides and cinnamides, with some compounds unique to the pith. This finding highlights a chimpanzee-guided discovery of a non-native plant with known bioactive properties. This study opens avenues for further research on its distribution, potential invasiveness, and potential uses for its biological effects by both humans and wildlife in Africa.