Exopolysaccharide Produced by Probiotic Bacillus albus DM-15 Isolated From Ayurvedic Fermented Dasamoolarishta: Characterization, Antioxidant, and Anticancer Activities

Abstract

An exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus albuscDM-15, isolated from the Indian Ayurvedic traditional medicine Dasamoolarishta. Gascchromatography-mass spectrophotometry and nuclear magnetic resonance (NMR)canalyses revealed the heteropolymeric nature of the purified EPS with monosaccharidecunits of glucose, galactose, xylose, and rhamnose. Size-exclusion chromatography had shown the molecular weight of the purified EPS as around 240 kDa. X-raycpowder diffraction analysis confirmed the non-crystalline amorphous nature of the EPS. Furthermore, the purified EPS showed the maximum flocculation activity (72.80%) with kaolin clay and emulsification activity (67.04%) with xylene. In addition, the EPS exhibits significant antioxidant activities on DPPH (58.17 0.054%), ABTS (70.47 0.854%) and nitric oxide (58.92 0.744%) radicals in a concentration-dependent way. Moreover, the EPS showed promising cytotoxic activity (20 0.97 mg mL􀀀1) against the lung carcinoma cells (A549), and subsequent cellular staining revealed apoptotic necrotic characters in damaged A549 cells. The EPS purified from the probiotic strain B. albus DM-15 can be further studied and exploited as a potential carbohydrate polymer in food, cosmetic, pharmaceutical, and biomedical applications.