A recent study has revealed that wild chimpanzees in the Budongo Forest, Uganda, consume certain plants not only for their nutritional value but also for their medicinal properties. This groundbreaking research observed two habituated chimpanzee communities and identified behaviors suggestive of self-medication, such as bark feeding, dead wood eating, and pith-stripping.
The study, published Thursday in the journal PLOS One, was carried out by a team led by Elodie Freymann of the University of Oxford and Fabien Schultz of Neubrandenburg University of Applied Sciences in Germany, which found that chimpanzees were consuming a variety of plants with medicinal effects but little other nutritional value, often when they had a health issue such as an injury or a parasite.
The study focused on 17 botanical samples from 13 different plant species, including nine trees and four herbaceous plants.
Researchers extracted compounds from these plants using n-hexane, ethyl acetate, and methanol/water (9/1, v/v) and tested them for antibacterial and anti-inflammatory properties.
The antibacterial tests included a panel of multidrug-resistant bacteria, known as ESKAPE strains, while the anti-inflammatory tests targeted cyclooxygenase-2 (COX-2) inhibition activity.
The findings were remarkable: 88% of the extracts showed significant antibacterial activity, with 45 out of 53 extracts inhibiting bacterial growth by 40% or more at a concentration of 256 μg/mL.
The most potent antibacterial effects were observed in the n-hexane extract of Alstonia boonei dead wood and the methanol-water extract of Khaya anthotheca bark and resin.
These extracts effectively inhibited Staphylococcus aureus, Enterococcus faecium, and pathogenic Escherichia coli. Notably, chimpanzees with high parasite loads were seen ingesting these specific plants, suggesting a deliberate choice for their medicinal benefits.
In the anti-inflammatory tests, 33% of the extracts demonstrated substantial COX-2 inhibition, with the methanol-water extract of K. anthotheca bark and resin showing the strongest effect.
The fern Christella parasitica also exhibited significant anti-inflammatory properties, with its extract being consumed by an injured chimpanzee, a rare behavior in this population.
This research, supported by eight months of behavioral observations, underscores the importance of self-medication in wild chimpanzees.
The interdisciplinary approach, combining pharmacological analysis with observational and health data, provides valuable insights into the field of zoopharmacognosy, the study of how animals use plants for medicinal purposes.
Overall, the study highlights the sophisticated ways in which chimpanzees manage their health and well-being through natural resources, offering a deeper understanding of animal behavior and the potential for discovering new medicinal compounds.