Rutin: a pain-relieving flavonoid.

Rutin (vitamin P or rutoside) is a citrus flavonoid glycoside that has shown beneficial health effects in different organs against various conditions including inflammation and pain. The majority of rutin therapeutic benefits are ascribed to its antioxidant and anti-inflammatory properties. This review article discusses studies that investigated pain-relieving activity of rutin and summarizes the reported mechanisms of action. Rutin pain-relieving effect has been studied in streptozotocin-induced diabetes, chronic constriction injury, and oxaliplatin-, formalin-, acetic acid- and glutamate-induced nociception in mice or rats. Based on the literature, rutin analgesic effects are induced through potentiation of antioxidant arsenal, reduction of inflammatory cytokines (e.g., Tumor necrosis factor alpha (TNF-α) and interleukin-1β) levels, suppression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions and modulation of MAPK, NF-κB and Nrf-2/HO-1 signaling. Preclinical findings on rutin pain-relieving activity are promising, however, its safety profile needs to be more thoroughly investigated and clinical trials should be conducted to assess its analgesic effects in humans.