Abstract:
The immunomodulatory properties of methanol extract and fractions of Hoslundia opposita leaf on Delayed-Type Hypersensitivity (DTH), primary and secondary humoral response and in vivo leucocyte mobilization were evaluated. Acute toxicity test of crude extract and phytochemistry study was carried out. The methanol extract (ME) at 200, 400 and 800 mg/kg body weight produced significant (P<0.05) inhibition of DTH response in rat by 85, 75 and 85%. The n-hexane, ethyl acetate and methanol fractions at 200, 400 and 800 mg/kg body weight produced significant (P<0.05) inhibition of DTH response. Treatment of rats with single intraperitoneal injection of carrageenan after oral administration of extract and fractions resulted in an increase in leucocyte mobilization into the rat’s peritoneal fluid which was significant. The total leucocytes counts (TLC) were higher in the extract and fractions treated groups when compared to the control group. However a fall in primary and secondary antibody titre was observed with both ME and fractions suggesting that Hoslundia opposita may act through a cell mediated mechanism. The crude extract administered (orally) at 5000 mg/kg did not cause lethality after 48 h observation period. Phytochemistry tests revealed abundant presence of resins, terpenoids, flavonoids, saponins and glycosides in the fractions and crude extract. These findings suggest that these may be responsible for the immunomodulatory effect of the leaves of Hoslundia opposita. It was therefore recommended that further studies be done to identify and isolate the exact constituent responsible for the immunomodulatory effects and also establish mechanism of action of Hoslundia opposita Vahl (Lamiaceae).
