Orangutans Use Plant Extracts to Treat Pain

Medicine is not exclusively a human invention. Many other animals, from insects to birds to nonhuman primates, have been known to self-medicate with plants and minerals for infections and other conditions. Behavioral ecologist Helen Morrogh-Bernard of the Borneo Nature Foundation has spent decades studying the island's orangutans and says she has now found evidence they use plants in a previously unseen medicinal way.

During more than 20,000 hours of formal observation, Morrogh-Bernard and her colleagues watched 10 orangutans occasionally chew a particular plant (which is not part of their diet) into a foamy lather and then rub it into their fur. The apes spent up to 45 minutes at a time massaging the concoction onto their upper arms or legs. The researchers believe this behavior is the first known example of a nonhuman animal using a topical analgesic.

Local people use the same plant—Dracaena cantleyi, an unremarkable-looking shrub with stalked leaves—to treat aches and pains. Morrogh-Bernard's co-authors at the Czech Academy of Sciences, Palacky University Olomouc and the Medical University of Vienna studied its chemistry. They added extracts from it to human cells that had been grown in a dish and had been artificially stimulated to produce cytokines, an immune system response that causes inflammation and discomfort. The plant extract reduced the production of several types of cytokines, the scientists reported in a study published last November in Scientific Reports.

The results suggest that orangutans use the plant to reduce inflammation and treat pain, says Jacobus de Roode, a biologist at Emory University, who was not involved in the study. Such findings could help identify plants and chemicals that might be useful for human medications, de Roode says.

In creatures such as insects, the ability to self-medicate is almost certainly innate; woolly bear caterpillars infected with parasitic flies seek out and eat plant substances that are toxic to the flies. But more complex animals may learn such tricks after an initial discovery by one member of their group. For example, an orangutan may have rubbed the plant on its skin to try to treat parasites and realized that it also had a pleasant pain-killing effect, says Michael Huffman, a primatologist at Kyoto University, who was not involved in the new research. That behavior may then have been passed on to other orangutans. Because this type of self-medication is seen only in south-central Borneo, Morrogh-Bernard says, it was probably learned locally.

INTRODUCTION

It wouldn’t come as a surprise to anyone that active pharmaceutical ingredients (APIs) come in a wide variety. Small molecule, large molecule, peptide, monoclonal antibody, innovative, generic; the list goes on. These molecules have the ability to cure or mitigate debilitating conditions that can change a person’s life forever. It makes sense, then, that these ingredients are of primary importance in a formulation, and appropriate measures should be taken to maintain their stability and efficacy. As these APIs become more complex, they also become increasingly vulnerable to a series of different degradation pathways. Changes in pH environments can cause acidification and lead to breakdown. Exposure to moisture can initiate hydrolysis and subsequently lead to the formation of secondary by products. Residual catalyst that isn’t removed from an excipient can trigger side reactions and perpetuate degradation of not just the API, but everything else in the formulation. To combat this, formulators will typically front-load their formulations to compensate for this anticipated loss. However, this does not end up being a practical solution, as the degradants are still forming, and becomes an even bigger concern when the cost of developing the formulation becomes even higher. As a result, the more practical solution is to ensure that the remaining ingredients in the formulation are of the highest quality and purity. This certifies the drug will not degrade, and that efficacy and longevity are maintained.