Introduction: Pain is one of the most common clinical symptoms . This
review aims to describe research on herbs and their active ingredients in treating pain
and provide a valuable reference for the development and utilization of analgesic
traditional Chinese medicine (TCM).
Areas covered: The literature search was performed from 1995 to October 2016,
covering the relevant studies that concern the treatment of pain with TCM. Active
ingredients extracted from TCM with analgesic activity are summarized and classified
into six categories, including polysaccharides, saponins, alkaloids, flavonoids,
terpenoids, and other constituents.
Expert opinions: There are two pathways constituting the analgesic mechanisms of
TCM: through the central nervous system and the peripheral nervous system. The
former pathway includes increasing the content of endogenous analgesic substances
like opiate peptide, cutting down the second messenger of neurotransmitter like nitric
oxide (NO), reducing the content of prostaglandin E2 (PGE2) in brain tissues, blocking
the central calcium channel, reducing excitatory amino acids in brain tissues, inhibiting
their receptors and raising the content of the central 5-hydroxytryptamine (5-HT). The
latter one usually involves the decrease in the secretion of peripheral algogenic
substances, the induction of pain-sensitive substances, the accumulation of a local
algogenic substance, the increase in the release of peripheral endogenous analgesia
materials and the regulation of c-Fos gene (immediate early gene).