Phytochemical, acute toxicity and anti-inflammatory studies on aqueous extract of Hallea rubrostipulata stem bark

The ethnomedicinal use of Hallea rubrostipulata stem bark as a remedy against malaria necessitated this study on its anti-inflammatory properties. The aqueous stem bark extract was subjected to phytochemical screening for the alkaloids, tannins, saponins, terpenes and flavonoids as secondary metabolites. Acute toxicity study of the aqueous extract showed that the extract was safe up to 2000mg/kg. The anti-inflammatory activity was examined using the carrageenan –induced oedema and formalin test in rats. The extract at doses (200, 400 and 800mg/kg) and indomethacin significantly (P<0.05) inhibited the carrageenan- induced oedema at the 3rd and 5th hour after carrageenan injection. The formalin test for aqueous extract of Hallea rubrostipulata bark demonstrated a significantly (P<0.005) but moderate percentage of inhibition in the late phase (inflammatory phase). In conclusion, the present results revealed the presence of phytochemical constituents which are known to mediate anti-inflammatory effects in carrageenan-induced oedema in rats. The anti-inflammatory effect of the aqueous extract of Hallea rubrostipulata bark might explain the effectiveness of the plant in malaria therapy traditionally.