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

EVALUATION OF THE ANTI-MYCOBACTERIAL, ANTI-OXIDATIVE AND ANTI-PROLIFERATIVE ACTIVITIES OF RUBIA CORDIFOLIA ETHANOLIC LEAF EXTRACT SUB-FRACTIONS IN HUMAN LYMPHOCYTES AND NEUTROPHILS

Background. Rubia cordifolia has been used to treat various diseases and exhibits antimicrobial, anti-inflammatory, analgesic and antidiarrheal activities. The plant has not been investigated for its anti-mycobacterial activity against virulent tuberculosis strains as well as cytotoxic and anti-oxidant activities in mononuclear cells and neutrophils. Methods. Ethanolic and dichloromethane leaf extract fractions of Rubia cordifolia (0.2- 125μg/ml) were screened for anti-mycobacterial activity using a fluorescent microplate assay. The anti-oxidant activity of the fractions was tested using the radical scavenging assay, while their cytotoxicity to lymphocytes was measured using the WST-8 assay. Reactive oxygen species production by neutrophils exposed to fractions was tested using Cell Meter™ Fluorimetric ROS Assay kit. Results. The ethanolic leaf fractions exhibited overall superior anti-mycobacterial activity than the dichloromethane group and were further screened for anti-oxidant and cytotoxic activities. Ethanolic sub-fractions K2F-3.2, K2F-3.3 and K2F-3.4 showed significant antioxidant activities at concentration of 50 μg/ml to 200 μg/ml and higher in both the cell free-based radical scavenging activity and total reactive oxygen species production assays. For lymphocytes, the test agents showed anti-proliferative activity at 25 μg/ml to 200 μg/ml for sub-fraction K2F-3.3B and 50 μg/ml to 200 μg/ml for agents K2F-3.2 and K2F-3.4. Conclusion. The current study is the first to record the in vitro anti-mycobacterial, anti-oxidant and cytotoxic activities of Rubia cordifolia plant leaf extract sub-fractions using the given experimental setups and further research activities to identify the bioactive components are to be pursued