Menthol, Camphor, Wintergreen oil & Oleoresin capsicum
Local Pain Reliever
The fresh or dried fruits of different capsicum species are used medicinally. Capsicum oleoresin is prepared by extracting the crushed capsicum with volatile solvents by percolation method. Preparation made from the oleoresin in cayenne and oleo-resin’s isolated constituent ‘Capsaicin’ is used as topical analgesic in OTC (overthecounter) market. The herb is indigenous to Mexico and Central America. Melhylsalicylate, menthol and camphor are originally derived from plants. Methyl salicylate is derived from oil of wintergreen, menthol is derived from mint and camphor is derived from a number of plants including Peppermin Eucalyptus and Cedar.
Capsicum induces selective analgesic effect by depleting substance P, a neuropeptide of 11 amino acids that mediates the transmission and modulation of pain impulses from the peripheral nerves to the spinal column. Capsicum initially stimulates substance P release from peripheral sensory C type nerve fibers, then prevents its reuptake and also blocks its transport within the neuron, which causes its eventual depletion resulting in analgesia. The mode of action of methyl salicylic acid is similar to that of aspirin and shows anesthetic properties by blocking the voltage-operated sodium channels in pain-receptor neurons. The menthol molecule binds and stimulates the TRPM-8 receptor protein that produces a sensation of cold (pain in extreme cases) when stimulated. FDA has approved camphor for topical use as a pain reliever and anesthetic. It acts as counter irritant and numbs the nerve endings that inhibit the transmission of pain sensation.