Chimpanzees appear to consume plants with medicinal properties to treat their ailments, according to a new study led by the University of Oxford. The research, published in PLOS ONE, provides compelling evidence that these primates intentionally seek out plants with health benefits.
EVIDENCE OF SELF-MEDICATION
Many plants produce compounds that have medicinal effects on humans and animals. Wild chimpanzees eat various plants, including some that are nutritionally poor but may treat or lessen symptoms of illness. It has been challenging to determine whether chimpanzees self-medicate or passively consume medicinal plants.
RESEARCH METHODOLOGY
Researchers combined behavioural observations of wild chimpanzees with pharmacological testing of the plants they eat. The study monitored the behaviour and health of 51 chimpanzees from two communities in Uganda’s Budongo Central Forest Reserve, who were accustomed to human presence.
PLANT COLLECTION AND TESTING
The team collected plant extracts from 13 species of trees and herbs suspected of being used by chimpanzees for self-medication. These plants included those eaten by sick or injured chimpanzees but not part of their regular diet, and plants previously suggested as medicinal.
The extracts were tested for anti-inflammatory and antibiotic properties at Neubrandenburg University of Applied Sciences, led by Dr. Fabien Schultz.
Findings
- 88% of plant extracts inhibited bacterial growth.
- 33% of extracts exhibited anti-inflammatory properties.
NOTABLE PLANTS
- Alstonia boonei: This tree in the Dogbane family showed the strongest antibacterial activity and also had anti-inflammatory properties. It is used in East African communities to treat bacterial infections, gastrointestinal issues, snake bites, and asthma.
- Khaya anthotheca: Bark and resin from the East African mahogany tree exhibited potent anti-inflammatory effects.
- Christella parasitica: Leaves from this fern showed strong anti-inflammatory properties. Researchers observed a male chimpanzee with an injured hand eating these leaves, likely to reduce pain and swelling.
- Scutia myrtina: Bark from the cat-thorn tree, consumed by a chimpanzee with a parasitic infection, had anti-inflammatory and antimicrobial properties.
BEHAVIORAL OBSERVATIONS
Researchers documented chimpanzees seeking out specific plants for their medicinal effects. For instance, a male with an injured hand ate leaves of the Christella parasitica fern, and an individual with a parasitic infection consumed Scutia myrtina bark, a plant previously not observed in their diet.
IMPLICATIONS FOR HUMAN MEDICINE
Lead author Dr. Elodie Freymann highlighted the potential for medicinal plants identified in this study to aid in developing new drugs, especially given the global health challenges of antibiotic-resistant bacteria and chronic inflammatory diseases.
PRESERVING NATURAL PHARMACIES
Dr. Freymann emphasized the importance of preserving forests like Budongo Central Forest Reserve, which serve as natural pharmacies. Observing other species in the wild can offer valuable medicinal knowledge.