A review on pain-relieving activity of berberine.

As isoquinoline alkaloid naturally occurs in Coptis and Berberis species, berberine (BER) has shown anti-oxidant, anti-tumour, anti-bacterial and hepatoprotective activities and beneficial effects against digestive, cardiovascular and neurological conditions. Also, BER antiinflammatory, pain-relieving and anti-cholinesterase activities were widely studied. The present overview discusses the analgesic effects of BER. Based on the literature, BER exerted pain-relieving activity against diabetic and chemotherapy-induced neuropathy, and sciatic nerve injury-induced pain via down-regulation of transient receptor potential vanilloid 1, suppression of NF-κB and modulation of μ and δ opioid receptors. Besides, BER could repress inflammatory markers tumour necrosis factor-α, interleukin-6 and IL-1β, as well as prostaglandin E2, inducible nitric oxide synthase and cyclooxygenase-2. The modulatory effects of BER on dopamine and N-methyl d-aspartate systems were also noted. Moreover, BER could induce Nrf2 expression but inhibits p38-MAPK and STAT3 phosphorylation. Noteworthy, anti-cholinesterase activity, which may potentially contribute to BER analgesic properties, warrants particular attention.