Total phenolics, flavonoids and antioxidant activity of macroalgae fermented with lactic acid bacteria

Abstract

a,a-diphenyl-b-picrylhydrazyl (DPPH) free radical scavenging activity, antioxidant capacity, total phenolic and flavonoids contents of lactic acid bacteria fermented-fresh water macroalgae extracts were studied. Three treatments of macroalgae; 1) Spirogyra spp. Ubon Ratchathani Province, 2) Khai Ubon Ratchathani Province (Cladophora spp. and Microspora spp.) and 3) Khai Nan Province (Cladophora spp. and Microspora spp.) were studied. The fermented macroalgae were extracted with ethanol. The percentage of DPPH free radical scavenging activity of the ethanolic extracts of the lactic acid bacteria fermented macroalgae of the treatment 1, 2 and 3 were 84.77, 0.67 and 77.06, respectively. In addition, the antioxidant capacities (10 g/l) were 63.45, 36.50 and 31.75 mg AE/g of extract as ascorbic acid equivalent, respectively. Total phenolic contents of the treatment 1, 2 and 3 were 29.54±0.93, 37.23±1.92 and 2.55±1.06 mg/g as gallic acid equivalent of extract, respectively. The total flavonoid contents of the treatment 1, 2 and 3 were 21.48, 11.55 and 13.48 mg/g as quercetin equivalent of extract, respectively. Extracts of Spirogyra sp. fermented with lactic acid bacteria (treatment 1) show the highest flavonoid contents, antioxidant capacity and DPPH free radical scavenging activity.