In-vivo immunomodulatory activity of standardized Stereospermum suaveolens (Roxb.) DC. root extract

Abstract

Stereospermum suaveolens (Roxb.) DC. is used in various Ayurvedic formulations to treat variety of disorders including inflammations, asthma, blood disorders, fevers, liver disorders etc. Quantification of the bioactive compound in S. suaveolens root extract (SSRE) was determined through RP-HPLC, in order to standardize the plant material with optimal concentration of known active constituents present there in. The immunomodulatory potential of SSRE was determined for its effects on non-specific immune functions against sheep red blood cells antigenic challenge using in- vivo models. The assay included total and differential leu- kocyte counts, nitroblue-tetrazolium reduction test, neutro- phil adhesion test, phagocytic activity and delayed type hypersensitivity (DTH) reaction. In RP-HPLC analysis, the contents of dehydro-α-lapachone and lapachol in SSRE was found to be 0.043±0.003 and 0.16±0.002 % (w/w), respec- tively. Standardized SSRE (100-300 mg/kg) increased the total leukocyte count and the population of monocyte and neutrophil in rats. Further, treatment with SSRE increased the neutrophil adhesion to nylon fibres, DTH response, phagocytic activity and intracellular killing potential of phagocytesinadosedependentmanner.Theimmunostimulatory potential of SSRE at 300 mg/kg was found to be very significant (p<0.001) in compared to the control. These findings suggest that SSRE can able to stimulate the innate defence mechanisms of an individual and it can be considered as an alternative therapy to boost the innate immune functions during the impaired im- munological conditions.