Pharmacological investigations of Sapindus trifoliatus in various in vitro and in vivo models of inflammation

OBJECTIVE: To investigate the effect of lyophilized aqueous extract of pericarps of Sapindus trifoliatus (ST) in various in vitro and in vivo inflammatory models. METHODS: ST was studied for its in vitro inhibitory activity against 5-lipoxygenase (5-LO), cyclo-oxygenase (COX), leukotriene B₄ (LTB₄) and nitric oxide synthase (NOS). At doses 20 and 100 mg/kg, i.p. ST was evaluated in acute pedal inflammation induced by carrageenan, histamine, serotonin and zymosan in rats and mice. Further, the effect of topical application of the extract (1 mg and 5 mg) on ear inflammation induced by various inflammatory agents like -O-tetradecanoyl-phorbol 13-acetate (TPA) or capsaicin or arachidonic oxazolone or dinitrofluorobenzene (DNFB) was also investigated. RESULTS: In vitro evaluation of the extract revealed its inhibitory activity against the major inflammatory mediators 5-LO, COX, LTB₄ and NOS. The extract significantly inhibited the pedal inflammation produced by carrageenan, histamine, serotonin and zymosan. Further, topical application of ST significantly inhibited the ear inflammation induced by acute and multiple applications of TPA and acute application of capsaicin or arachidonic acid. However, the extract failed to inhibit ear inflammation induced by oxazolone or DNFB. CONCLUSION: ST has antiinflammatory activity possibly mediated through 5-LO and COX pathways.