A few weeks ago it was learned that an orangutan was applying a poultice based on a medicinal plant to an ugly wound on its face. Now, thousands of kilometers away, on another continent, it is revealed that another great ape, the chimpanzee, uses a range of vegetables, from leaves to tree bark, to treat its ailments. The analysis of these plants, some common in traditional medicine, has shown that the majority have antimicrobial activity and, a third, anti-inflammatory activity. The authors of this work believe that great apes may one day help humans discover new drugs.
In the reserve of Budongo forest (Uganda) there are several communities of chimpanzees. Two of them, those of Sonso and Waibira, are accustomed to the presence of scientists, who have been studying the two populations (the first of 68 individuals and the second of 105) since the last century. Occasionally, they have been seen eating plants of unknown or no nutritional value. Suspecting its possible medicinal use, a group of researchers collected dozens of samples from 17 parts of 13 different species (from some they collected leaves, bark or dead wood) that were not part of their usual diet. In parallel, they analyzed stools and urine from both groups to detect pathologies, especially following the behavior and condition of 51 of them.
As detailed in the scientific magazine PLOS ONE, the samples were analyzed to determine their anti-inflammatory and antibiotic properties at the Neubrandenburg University of Applied Sciences (Germany), in the laboratory led by Dr. Fabien Schultz, co-author of the study. They obtained 53 extracts through different methods and the next thing they did was analyze their pharmacological effects.
“We tested these extracts for their antibacterial and anti-inflammatory effects,” says Schultz, an ethnopharmacologist who has spent years studying the bridges between traditional medicine in human communities and the medicinal plants consumed by primates. “In our antibiotic trials in vitro, we have investigated the effects of the extracts against the growth of 11 different strains of bacterial pathogens. These included clinical isolates of the so-called ESKAPE pathogens, which the WHO considers one of the greatest threats to global health,” he adds. Among the bacteria there are some pathogenic ones, such as Escherichia coliand multi-resistant, such as Staphylococcus aureus either Klebsiella pneumoniae. “All the strains used in our study had resistance to multiple drugs, often against the most important antibiotics that exist,” completes the German researcher. They almost made it: 45 of the plant extracts (88%) showed at least some antibacterial activity at the lowest test concentration against at least one strain.
They showed that the collected plants had antibacterial effects, but, as Schultz points out, this “does not tell us anything about the potency of these herbal remedies; simply that there are active ingredients that cause such effects present.” Potency was evaluated using dose-response assays. They thus identified the most powerful extracts, highlighting the one obtained from the dead wood of the Alstonia boonei, a deciduous tree present in much of sub-Saharan Africa and used by many human communities as medicine. In the experiments, its greatest inhibitory capacity was shown against a bacteria feared in hospitals, S. aureusand another that, common to the human digestive system, can become pathogenic, causing meningitis in newborns, Enterococcus faecium. They also showed great antibiotic capacity against this bacteria and E.coli the bark and resins of the Khaya anthotheca, a large tree. In the last two years of monitoring, the researchers had observed several chimpanzees with intestinal parasites eating the wood of one and the bark and resin of the other.
“A chimpanzee with a damaged hand searched for leaves of a fern with strong anti-inflammatory properties”
Elodie Freymann, researcher at the University of Oxford
Until now, it was known that several communities of chimpanzees ingested leaves or other parts of plant species to combat their intestinal parasitic infections. In the case of many leaves, the healing effect is mechanical in nature, there is no active ingredient: incapable of being digested and populated with rough trichomes on their surface, they drag intestinal worms such as nematodes with them. But the use of plants with antibiotic activity had not been documented in this detail. And not just antibiotics.
As Oxford University researcher and first author of the study, Elodie Freymann, relates, “a chimpanzee with a damaged hand looked for leaves of a fern with strong anti-inflammatory properties; “no other individuals around it ate ferns, and this had only been seen once before in 30 years of observation.” The species of fern was specifically the Christella parasitica. A third of the species analyzed had some anti-inflammatory or analgesic effect. Although it is difficult to close the circle and connect intentionality with action and result, for Freymann, “this provides evidence to suggest that the chimpanzee may have sought out the ferns for their anti-inflammatory properties.” They are going to continue studying this to confirm that, at least in these communities, they look for certain plants and not others when they have a certain ailment and not another.
“It is important that we remember that wounds are not the only ailments that animals suffer, and that there will be internal diseases for which animals will need to self-medicate,” recalls the Oxford researcher. “This can be more difficult to study than wounds, because you can’t physically see what’s happening to the animal you’re studying, so doing so requires taking a multidisciplinary approach, analyzing behavioral anecdotes alongside health data and pharmacological results. “, Add. Connecting the history of these chimpanzees with that of the orangutan Rakus, Freymann ends by highlighting: “The natural world is full of medicines on which we depend, as well as our non-human neighbors. If we want to keep these animals safe, we must protect their medicine cabinet.”
Even being selfish. His research colleague, ethnopharmacologist Schultz, who is now investigating the use of medicinal plants by mountain gorillas, recalls that “finding a highly successful medicine from natural materials is often like finding the needle in the haystack.” ; however, our work has contributed to drug discovery in its early stages.” Of course, there would still be a lot to do, an extract can contain more than 1,000 different substances. “We do not know (yet) what substances are present, whether they are new to science and how powerful they are. There can also be synergistic effects, that is, a combination of substances causes the effect, not just one,” recalls the German scientist. Furthermore, they have only provided scientific evidence of its effectiveness in vitro and it remains to isolate the active ingredient(s) and whether they would be applicable in animal tests, but, concludes Schultz, “this is a very long road to travel, but in theory, humans can learn from our closest animal ancestors and, some “One day, human lives may be saved thanks to the knowledge of chimpanzees.”
You can follow SUBJECT in Facebook, x and instagramor sign up here to receive our weekly newsletter.
#Chimpanzees #antibiotics