427IN VITRO EFFECT OF AQUEOUS EXTRACT, HEXANE AND METHANOL FRACTIONS OF Boswellia dalzeilii, Hutch (Family: Burseraceae) IN IMMUNOMODULATORY ACTIVITIES OF HUMAN MONOCYTES / MACROPHAGESBoswellia dalzeilii is a species of the family dalzeilii that grows in the northern part of Cameroon. Species of this genus have been considered as to have a potent immunological effect; however there are no reports about its immunomodulatory activity. In this study, the aqueous extract as well as the hexane and methanol fractions of B. dalzielii stem bark were investigated for immunomodulatory activities by measuring the proliferative response of monocytes, and the phagocytic activity, nitric oxide production and lysosomal enzyme activity of macrophages. Results showed that treatment with 160-2560 µg/ml of the aqueous extract and methanol fraction stimulated monocytes proliferation in a dose-dependent manner. They also stimulated phagocytosis dose-dependently after 24, 48 and 72 h of incubation compared to untreated control. However, the phagocytic index decreased with time for the aqueous extract. Lysosomal enzyme activity was stimulated dosedependently only by the methanol fraction, however it started to decrease at the concentration of 2560 µg/ml. The hexane fraction did not affect monocyte proliferation however it stimulated phagocytosis, with the phagocytic index increasing over time. The hexane fraction also decreased NO production but no significant change in lysosomal enzyme activity was observed. The above results show that the B. dalzielii stem bark probably contains some active ingredients that could be developed for such immunity problems as was been claimed by traditional medical practitioners.oumar.mahamat@yahoo.frResearch522014 Boswellia dalzielii,Index phagocytic,NO production,Lysosomal enzymz activity,MacrophagesOumar Mahamat,Tume Christopher,Kamtchueng Monique Odette,Kamanyi Albert Department of Biological Sciences, Faculty of Science, University of Bamenda, Cameroon,Department of Biochemistry, Faculty of Science, University of Dschang, Cameroon.,Department of Biochemistry, Faculty of Science, University of Dschang, Cameroon.,Department of Animal Biology, Faculty of Science, University of Dschang, Cameroon