The analgesic potential of glycosides derived from medicinal plants

Pain represents an unpleasant sensation linked to actual or potential tissue damage. In the early phase, the sensation of pain is caused due to direct stimulation of the sensory nerve fibers. On the other hand, the pain in the late phase is attributed to inflammatory mediators. Current medicines used to treat inflammation and pain are effective; however, they cause severe side effects, such as ulcer, anemia, osteoporosis, and endocrine disruption. Increased attention is recently being focused on the examination of the analgesic potential of phytoconstituents, such as glycosides of traditional medicinal plants, because they often have suitable biological activities with fewer side effects as compared to synthetic drugs. The purpose of this article is to review for the first time the current state of knowledge on the use of glycosides from medicinal plants to induce analgesia and anti-inflammatory effect. Various databases and search engines, including PubMed, ScienceDirect, Scopus, Web of Science and Google Scholar, were used to search and collect relevant studies on glycosides with antinociceptive activities. The results led to the identification of several glycosides that exhibited marked inhibition of various pain mediators based on different well-established assays. Additionally, these glycosides were found to induce most of the analgesic effects through cyclooxygenase and lipoxygenase pathways. These findings can be useful to identify new candidates which can be clinically developed as analgesics with better bioavailability and reduced side effects. Graphical abstract Analgesic mechanisms of plant glycosides.