- Seeking plants with potential medical properties, a team of researchers in Gabon looked to the practices of two distinct groups: traditional healers living on the fringes of Gabon’s Moukalaba-Doudou National Park, and the gorillas that live inside the park, which are known to host pathogens like E. coli without developing serious illnesses.
- The researchers interviewed Indigenous Vungu healers and herbalists about their medical usage of local plants, then followed gorillas in the park to observe which plants the apes also consumed, ultimately selecting four plant species to test.
- The bark extracts tested by the team were found to have antimicrobial and antioxidant properties, as well as other bioactive compounds.
- This research, one expert says, highlights the shared evolutionary history of humans and gorillas, and the importance of preserving both apes and their habitats.
For the Indigenous Vungu people living along the border of Gabon’s Moukalaba-Doudou National Park, the forest here has long been a source of traditional medicines.
So when researchers set out to determine the bioactive properties of plants consumed by the park’s western lowland gorillas (Gorilla gorilla gorilla), and which the Vungu also use for medicine, the community’s knowledge proved vital to their findings.
Leresche Oyaba Yinda, lead author of the resulting study published in PLOS ONE, says interviewing the local people, traditional healers and herbalists about the medicinal uses of plants eaten by gorillas “was a decisive step in the effectiveness of our study.”
“Indeed, these ethnobotanical and ethnopharmacological surveys carried out among the [Indigenous people] of Moukalaba-Doudou National Park were like a compass pointing us in the direction of our questioning,” says Yinda, a scientist from the bacteriology lab at the Interdisciplinary Medical Research Center of Franceville in Gabon.
A growing body of research has established that nonhuman animals use plants, as well as animal or soil substances, to treat wounds or other health conditions. It’s also been found that some of the plants that animals consume for self-medication are also used medicinally by humans.
In the current study, a team of 13 researchers aimed to determine the medical properties of plants consumed by gorillas that are also part of the Vungu people’s traditional pharmacopeia.
Gorillas in the park are known to host pathogens, including forms of E. coli resistant to multiple drugs used by humans, without those pathogens progressing into serious disease. The researchers therefore hypothesized that gorillas’ consumption of bark and other plant parts with bioactive ingredients was likely enhancing their immunity.
For 10 days in August 2022, the researchers monitored the plants gorillas ate. Botanists on the team, with the help of traditional knowledge they had gathered from the community, collected fresh bark samples of plants that were also used medicinally by the local people. Ultimately, by cross-referencing both human medical usage and gorilla consumption, they selected four species to test: Ceiba pentandra, Myrianthus arboreus, Ficus ssp. and Milicia excelsa.
When they conducted lab tests on the extracts from the barks, they found the samples had antioxidant and antimicrobial properties. They also found organic compounds known to be active against malaria, diarrhea, inflammations and spasms.
The researchers say these findings justify the use of the barks in traditional medicine and point to a potential source for new bioactive compounds for use in the pharmaceutical, cosmetics and food industries.
Yinda says their Indigenous collaborators had “great interest” in the course of the research.
“They felt that their knowledge of traditional medicine and their pharmacopoeia would be enhanced by the results of the study. Our research team will make every effort to disseminate its findings to these local populations, whose contribution was considerable and undeniable,” he says.
However, the community wasn’t necessarily surprised that gorillas seek the same plants as they do for medicine.
“Given their knowledge of traditional medicine and the uses of selected plant organs, and the fact that they have almost always shared the same living ecosystem as gorillas, they were not fundamentally surprised by the self-medicating behavior of these animals, which they continually observe,” Yinda says.
For the scientists, the results of the study enable them to draw lessons in adding value to the crude extracts from the barks of the selected plants for production of improved traditional medicines.
“In addition, the results of our study provide data demonstrating the importance of conserving this rich ecosystem, in which humans and gorillas evolve in symbiosis,” Yinda says.
According to researchers, this sort of data is particularly important for low- and middle-income nations where well-planned exploration of biodiversity for the development of valuable products could help in nature conservation, “ultimately benefiting humankind in the long run.”
Denis Ndeloh Etiendem, a Cameroonian primatologist who previously conducted a study on traditional ecological knowledge and the conservation of Cross River gorillas (G. g. diehli) in his country, says traditional knowledge reinforces the interconnectedness between humans and gorillas and highlights the importance of preserving both the species and their habitats.
“By protecting the forest ecosystems where these medicinal plants grow, we safeguard a living pharmacy that benefits both gorillas and humans,” Etiendem tells Mongabay in an email.
Etiendem, who wasn’t part of the recent study, says the fact that both humans and gorillas rely on the same medicinal plants reminds us of our shared evolutionary history.
“It also emphasizes the urgent need to address the threats gorillas face from habitat loss and hunting. Their extinction would not only mark the loss of a species but would also have detrimental effects on human survival, particularly in terms of our relationship with the ecosystems we both depend on,” he says.
Since the tropical rainforests where gorillas live are known to be reservoirs of both known and emerging infectious diseases, understanding how gorillas survive in the rapidly changing ecosystems, including their use of medicinal plants, could inform modern human medicine.
“We cannot afford to let gorillas go extinct — it would be a loss not only for biodiversity but for human health,” Etiendem says.
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Citation:
Yinda, L. E., Onanga, R., Obiang, C. S., Begouabe, H., Akomo-Okoue, E. F., Obame-Nkoghe, J., … Godreuil, S. (2024). Antibacterial and antioxidant activities of plants consumed by western lowland gorilla (Gorilla gorilla gorilla) in Gabon. PLOS ONE, 19(9), e0306957. doi:10.1371/journal.pone.0306957
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