Georgofili World

Newsletter of the Georgofili Academy

Recent discovery of chili peppers’ analgesic role

The health effects of hot chili peppers in our diet have been debated for some time and numerous biomedical studies have been carried out regarding this topic. Many results are favorable even if there are some contraindications that have often been questioned by the majority of experts.
Not only has the antibacterial role of hot chili peppers been ascertained but also its high vitamin-C content antioxidant power, and positive digestive effect—to mention just some of its properties.
In early 2015, the use of hot chili peppers as a painkiller was authoritatively confirmed.
As is well-known, hot chili peppers owe this effect to the presence in their fruit -unique in the vegetable world - of an alkaloid called capsaicin, a substance that “cheats” the TRPV1 receptor by making us feel a high temperature and therefore a strong burning sensation.
in February 2015, Science Signaling*, a scientific journal of the American Society for the Advancement of Science (AAAS), published an article on how this alkaloid works reporting the results of a carefully researched study carried out by a group of scientists from the Rutgers University Medical School (New Jersey). This substance has numerous properties often beneficial to human health. Specifically, capsaicin’s pain-relief action was analyzed, which takes place by inactivating the mechanosensitive channels found in the neuronal membranes. For a long time, it had been observed that, as a topical pain medication, capsaicin caused numbness in the tissue. However, researchers had never been able to understand how that effect was obtained. Now we know that the initial attenuation of pain is the consequence of capsaicin activating a vanilloid receptor’s (TRPV1) ion channels in the sensory neurons. It is interesting to observe that the term “vanilloid” derives from the sensitivity of those receptors reacting to all substances having a vanillic functional group (vanillin is the one that gives vanilla its characteristic smell) which is also precisely that of capsaicin, closely correlated structurally to vanillin. The final result is that prolonged stimulus with capsaicin desensitizes these neurons. The importance of this research carried out by the New Jersey group lies in having discovered the link between capsaicin’s heat-stimulating function (which everyone experiences when eating a hot chili pepper) and its ability to relieve neuralgic, neuropathic and muscle pain. Essentially, the activation of the TRPV1 receptor involves, in its turn, the (almost 100%) inhibition of other ion channels in the neuronal membrane, causing the attenuation of the above-mentioned conditions. What is unique in this study is how the biochemical processes that take place in one kind of channel regulate the activity of a different kind of ion channel. In other words, it is a cross-talk, i.e., an unusual “molecular dialogue”, between ion channels, mediated by specific molecules, phospholipids, which this same study also identified. 

Despite using terms unfamiliar to most people, I hope it can be understood how the studies being carried out on hot chili peppers are able to give us increasingly more scientific explanations on this special vegetable’s various positive roles for our well-being.

*"Borbiro I. et al., Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides. Science Signalling, doi:10.1126/scisignal.2005667,2015

Amedeo Alpi -