Zoopharmacognosy: the study of how animals self-medicate

A Sumatran orangutan named Rakus in Indonesia is seen two months after self-treating a wound with a medicinal plant. | Photo Credit: Reuters

In the May 2, 2024 issue of the magazine NatureIn the article titled ‘Active self-treatment of a facial wound by a male Sumatran orangutan with a biologically active plant’, Laumer et al. describe how this primate in Indonesia treats his facial wound by making a paste from a local plant. Fibrauria tinctoriaand applied it to the wound. An article published in Nature in 2012 by Matt Kaplan, titled: ‘Neanderthals ate their greens’, analysed the dental plaque of some Neanderthals from northern Spain, and found that they used plants such as yarrow and chamomile to get rid of infections and for their general health.

There are many plants that have been used by people around the world in traditional medicine, to overcome infections and for general health. A comprehensive review by R Raman and S Kandula (Resonance, 245-253, March 2008) explains that ecologist DH Janzen of the University of Pennsylvania coined the term ‘zoopharmacognosy’, and was the first to list animals that self-medicate by eating or topically applying specific plants, soil and insects. In addition to providing molecules necessary for metabolism and growth, these also provide disease treatment and protection against parasites. (‘Zoo’ refers to animals, and pharmacognosy refers to the study of medicines and tonics for health). In a 2012 paper entitled: ‘Zoopharmacognosy: the self-medicating behavior of animals’ in “Environmental Science, Biology”, Dr. E.M. Costa-Neto of Bahia, Brazil, and Joel Shurkin of Baltimore, in the Proceedings of the National Academy of Sciences, listed many plants and their roots, leaves and fruits that apes, monkeys, reindeer, bears and some birds (starlings) eat to stay healthy. Dogs self-medicate by chewing grass and vomiting to get rid of stomach infections. Pregnant lemurs nibble on tamarind leaves to aid milk production and pregnant elephants in Kenya eat the leaves of certain plants in the Boraginaceae family to induce labor. Many of these medicinal plants have been known in Africa, Egypt, the Middle East, India and China for over 3,000 years and are still used today.

Traditional medicines

Medicinal plant Fibrouria tinctoria The Sumatran orangutan contains the anti-inflammatory molecule berberine, used for wound healing.Akara Kunyi‘ Locally, the plant is used in the traditional medicine system there. And in the southern subtropical regions, its counterpart is called oleander and is used as a treatment for jaundice. The shrub aloe vera, found in India (where it is called ‘guar patta’ in Hindi and ‘katarazhai’ in Tamil) and many parts of Asia and Africa, has antimicrobial, anti-inflammatory and wound healing properties.

Many civilizations have recorded and used natural healing methods for thousands of years. China has had the Zhongyi system for 5,000 years, the Arab system for 4,000 years and the Indian Ayurvedic system for 5,000 years. They all use different plants, fruits and roots such as Rauwolfina serpentina (sarpagandha in Hindi), and holy basil (tulsi), aloe vera, wild garlic, onion, oregano, artichoke, camphor, coconut and castor oil. Natural product-based ‘chyawanprash’ is popular in India; a formula for it is recorded in the Charaka Samhita from about 700 BCE. We now look to biochemists and pharmaceutical companies for new natural product molecules.