Monascus spp. fermented brown seaweeds extracts enhance bio-functional activities

Abstract

Two species of brown seaweeds, Saccharina japonica and Undaria pinnatifida were fermented by the red molds; Monascus purpureus and Monascus kaoliang to increase their bio-functional properties. The phenolic contents of S. japonica fermented by M. purpureus (SjMp) and M. kaoliang (SjMk) were the highest 71.53 ± 2.25 and 66.50 ± 4.64 mg gallic acid equivalent/g extract, respectively, whereas the highest flavonoid content was evident in S. japonica fermented by M. purpureus (SjMp) and U. pinnatifida fermented by M. purpureus (UpMp) (27.93 ± 0.28 and 26.88 ± 1.24 mg quercetin equivalent/g extract, respectively). Reducing sugar, protein and essential fatty acids levels also increased in fermented seaweeds. The antioxidant activities of fermented seaweed extracts exhibited significantly (p < 0.05) lower IC50 values than those of unfermented extracts. S. japonica fermented by M. purpureus (SjMp) exhibited the lowest IC50 values of antidiabetic activities mediated by α-amylase and rat intestinal α-glucosidase (maltose and sucrose): 0.98 ± 0.10, 0.02 ± 0.07 and 0.08 ± 0.13 mg/mL, respectively. M. purpureus fermented S. japonica extract at 4.58 ± 0.85 μg/mL afforded 50% inhibition of lipase, which was the most effective of all samples tested in this regard. Extracts from brown seaweeds fermented by Monascus spp. exhibited increased phenolics and flavonoids contents associated with strong in vitro bio-potential, DNA protection and the absence of any toxic effect on intestinal epithelial Caco-2 cells. Thus, fermented seaweed extracts may be recommended as food ingredients or therapeutic diet for patient suffering from oxidative stress, hyperglycemia and hyperlipidemia