In vitro immune-modulatory potential of crude extract of leaf of Albizia gummifera against stimulated peripheral blood mononuclear and raw cells

Background: Albizia species including A. gummifera have been used in folk medicine for the treatment of various conditions by many cultural groups. Apart from its anti-parasitic and antimicrobial activity associated with its use, Albizia gummifera have not been investigated for either its anti-inflammatory properties or anti-proliferative effect in vitro.Materials and Methods: Extracted acetone crude extract of plant material was tested for the presence of various secondary metabolites using chemical tests while the anti-proliferative effect against peripheral blood mononuclear were tested using the WST-1 assay. Nitric oxide production by RAW cell line exposed to extract was also tested using Griess assay as well as the production of interleukin- 2 in medium of cultured PMBC using an enzyme-linked-immunosorbent assay (ELISA) kit.Results: Phytochemical testing of acetone leaf extracted was shown to be positive for flavonoids, saponins and tannins. The extract was shown to dose-dependently inhibited proliferation of mononuclear cells while promoting that of RAW cells (p<0.05). The production of IL-2 by mononuclear cells and nitric oxide release by RAW cells were inhibited and stimulated respectively (p<0.05) in both cell types. The extract was also shown to elicit significant anti- and pro-inflammatory potential at concentration above 20 and 40 μg/ml, in both cell types respectively.Conclusion: Further laboratory research is required to elucidate the anti- and pro-inflammatory biochemical pathways as shown by the in vitro immune-modulatory modalities of this plant species. It is also important to further identify bioactive entities of Albizia gummifera responsible for the observed activities.Key words: Albizia gummifera, cell proliferation, Interleukin-2, nitric oxide, phytochemistry