Abstract

Free radical-scavenging antioxidants have the potential as protective agents against various degenerative diseases caused by oxidative damage. Microorganisms are shown to be a promising new source of natural antioxidants. In the present study, supernatant (crude extract) and different solvent extracts (ethyl acetate, n-butanol, dichloromethane) of Saccharomyces boulardii’s growth were evaluated for the antioxidant activity using free radical scavenging (1,1-Diphenyl-2-picryl hydrazyl; DPPH) assay, superoxide radical scavenging (nitroblue tetrazolium; NBT) assay, and by estimating total phenolic and flavonoid contents (TPC and TFC). Antioxidative potential of S.boulardii extract was also tested in biological system, i.e. A549 lung cancer cell line using dichlorofluoroscein diacetate (DCF-DA) assay. Organic extracts were further explored by HPLC and mass spectrometry techniques to identify active principles responsible for antioxidant activity. Comparative studies on antiradical ability (DPPH, NBT) revealed that crude extract has the highest activity than its other solvent counterparts as evident by its lower IC50 values and higher TPC and TFC. In vitro studies also showed that S.boulardii extracts effectively quench intracellular reactive oxygen species. Vanillin was identified as one of the contributing antioxidant. It was found that S.boulardii extract is an efficient scavenger of free radicals and can be exploited as a potential new source of natural antioxidants.

Key words: 1,1-Diphenyl-2-picryl hydrazyl; Dichlorofluoroscein diacetate; Nitrobluetetrazolium; Total phenolic content; Total flavonoid content