Anti-inflammatory properties of cryptolepine

Cryptolepine is the major alkaloid of the West African shrub, Cryptolepis sanguinolenta. Cryptolepine has been shown to inhibit nitric oxide production, and DNA binding of Nuclear Factor-kappa B following inflammatory stimuli in vitro. In order to validate the anti-inflammatory property of this compound in vivo, we investigated its effects on a number of animal models of inflammation. Cryptolepine (10-40 mg/kg i.p.) produced significant dose-dependent inhibition of the carrageenan-induced rat paw oedema, and carrageenan-induced pleurisy in rats. These effects were compared with those of the non-steroidal anti-inflammatory drug indomethacin (10 mg/kg). At doses of 10-40 mg/kg i.p., cryptolepine inhibited lipopolysaccharide (LPS)-induced microvascular permeability in mice in a dose-related fashion. Oral administration of up to 40 mg/kg of the compound for four consecutive days did not induce gastric lesion formation in rats. Analgesic activity was also exhibited by cryptolepine through a dose-related (10-40 mg/kg i.p.) inhibition of writhing induced by i.p. administration of acetic acid in mice. The results of this study reveal that cryptolepine possesses in vivo anti-inflammatory activity.