OBJECTIVE: The present study evaluated the immunosuppressive effects of 80% ethanol extract of of AM leaves in male Wistar rats on different parameters of humoral and cellular immune responses.
METHODS: AM leaf extract (AMLE) was analyzed using UHPLC-MS/MS to profile its secondary metabolites. AMLE was rich in polyphenols which include (epi)catechin-(epi)catechin-(epi) catechin, caffeic acid, coumaroylquinic acid, hyperin, kaempferol, quinic acid and rutin. The rats were administered 100, 200 and 400 mg/kg bw of the extract daily for 14 days. The effects of AMLE on innate immune responses were determined by evaluating phagocytosis, neutrophils migration, reactive oxygen species (ROS) release, CD11b/CD18 integrin expression, and ceruloplasmin, lysozyme and myeloperoxidase (MPO) levels. The adaptive immune parameters were evaluated by immunizing the rats with sheep red blood cells (sRBC) on day 0 and administered orally with AMLE for 14 days.
RESULTS: AMLE established significant immunosuppressive effects on the innate immune parameters by inhibiting the neutrophil migration, ROS production, phagocytic activity and expression of CD11b/CD18 integrin in a dose-dependent pattern. AMLE also suppressed ceruloplasmin, MPO and lysozyme expressions in the rat plasma dose-dependently. AMLE dose-dependently inhibited T and B lymphocytes proliferation, Th1 and Th2 cytokine production, CD4+ and CD8+ co-expression in splenocytes, immunoglobulins (IgM and IgG) expression and the sRBC-induced swelling rate of rat paw in delayed-type hypersensitivity (DTH).
CONCLUSION: The strong inhibitory effects on the different parameters of humoral and cellular responses indicate that AMLE has potential to be an important source of effective immunosuppressive agents.
METHODS: Two-fold serial micro-dilution method was used to measure minimal inhibitory concentration (MIC) of aqueous extracts of Gt, Sp and their combinations. Adsorption to hexadecane was used to determine the cell surface hydrophobicity (CSH) of bacterial cells. Glass beads were used to mimic the hard tissue surfaces, and were coated with saliva to develop experimental pellicles for the adhesion of the primary colonizing bacteria.
RESULTS: Gt aqueous extracts exhibited better anti-plaque effect than Sp aqueous extracts. Their combination, equivalent to 1/4 and 1/2 of MIC values of Gt and Sp extracts respectively, showed synergistic anti-plaque properties with fractional inhibitory concentration (FIC) equal to 0.75. This combination was found to significantly reduce CSH (p<0.05) and lower the adherence ability (p<0.003) towards experimental pellicles.
CONCLUSION: Combination between Gt and Sp aqueous extracts exhibited synergistic anti-plaque activity, and could be used as a useful active agent to produce oral health care products.