Investigation of the anti-inflammatory and antinociceptive activities of Hymenocardia acida Tul. (Hymenocardiaceae)

Abstract

Hymenocardia acida Tul. (Hymenocardiaceae) locally called Orupa, is traditionally used for the treatment of inflammation, including arthritis, rheumatic pain and toothache. The potential antiinflammatory and antinociceptive activities of the aqueous leaf extract of this plant were evaluated in animal models. The extract (50, 100 and 200 mg/kg) significantly (P < 0.05) and dose - dependently inhibited carrageenan and egg albumin-induced rat paw oedema development compared with control group. At 3 h of post-carrageenan administration, the highest dose of the extract (200 mg/kg, p.o) inhibited oedema formation by 66.67%. The reference drug used, indomethacin (10 mg/kg, p.o), gave an inhibition of 72.22%. The inhibitory activity shown by the aqueous leaf extract of H. acida over a period of 6 h in the carrageenan and 3 h in the egg albumin-induced paw inflammation models was comparable to that exhibited by the reference drugs used, indomethacin and cyproheptadine (10 mg/kg, p.o). The extract elicited a significant analgesic activity in the tail immersion test as evidenced by the increase in latency time in seconds as compared with the control at the end of 20 min. In the acetic acid-induced writhing model, the extract showed a dose-dependent reduction in the number of writhes at 50, 100 and 200 mg/kg when compared to the control group. The 200 mg/kg dose produced a complete protective effect, as no abdominal constriction was observed. The results obtained in this study provide some justification for the folkloric uses of H. acida as a remedy for relieving pain and  inflammation.

Key words: Anti-inflammatory activity, antinociceptive activity, carrageenan, egg-albumin, Hymenocardia acida.