Anti-inflammatory and antinociceptive activities of Homalium letestui

Context: Homalium letestui Pellegr (Flacourtiaceae) is used in various decoctions traditionally by the Ibibios of the Niger Delta of Nigeria to treat stomach ulcer, malaria and other inflammatory diseases, as well as an aphrodisiac. Objective: To investigate the anti-inflammatory and antinociceptive activities of the stem extract of the plant. Materials and methods: The ethanol stem extract (500, 750, 1000 mg/kg, i.p.) of H. letestui was investigated for anti-inflammatory activity using carrageenan, egg albumin-induced and xylene-induced ear edema models and analgesic activity using acetic acid-induced writhing, formalin-induced paw licking and thermal-induced pain models. The ethanol extract was administered to the animals orally, 30 min to 1 h depending on the model, before induction of inflammation/pain. The LD50 was also determined. GC-MS analysis of dichloromethane fraction was carried out. Results: The extract caused a significant (p<0.05-0.001) reduction of inflammation induced by carrageenan (8.3-70.0%), egg albumin (10.0-71.42%) and xylene (39.39-84.84%). The extract also reduced significantly (p<0.05-0.001) pain induced by acetic acid (44.22-73.65%), formalin (55.89-79.21%) and hot plate (93.0-214.5%). The LD50 was determined to be 4.38 +/- 35.72 g/kg. Discussion and conclusion: The results of this study suggest that the ethanol stem extract of H. letestui possesses anti-inflammatory and analgesic properties which may in part be mediated through the chemical constituents of the plant as revealed by the GC-MS.