This study was performed to investigate the antioxidant and antidiabetic activities of soybean fermented with Monascus. Also, the changes in the content of isoflavones and Monacolin K were analyzed. It was observed that the glycoside forms of daidzin and genistin were converted to aglycones of daidzein and genistein within 6 days of fermentation. The product can be used as a health functional material that can increase bioavailability. Monacolin K production was found to increase significantly with the progression of fermentation with an increase to 0.04 mg/g and 0.44 mg/g on 6 and 12 days of fermentation, respectively. The DPPH radical scavenging activity of soybean fermented with Monascus was significantly increased compared to that of soybean. The protein expression of inflammation-related genes (TNF-α, IL-6, and COX-2) in the MIN cell was significantly increased in the presence of alloxan compared to the normal group, but a decrease was observed in the presence of soybean fermented with Monascus. In conclusion, soybean fermented with Monascus showed the highest antidiabetic and antioxidant effects. These results suggest that soybean fermented with Monascus has the potential to be used as a beneficial ingredient with antidiabetic and antioxidant effects.

In this study, we assessed antioxidant, anti-diabetic, and anti-Alzheimer activities of Opuntia ficus-indica var. saboten (OFI) at harvest time. OFIs were cultivated December 2015~November 2016 in Jeju island. The 70% ethanol extracts of OFI were used to investigate total polyphenol and flavonoid contents, antioxidant(DPPH and ABTS radical scavenging assay), anti-diabetic(yeast α-glucosidase and rat α-glucosidase inhibition assay), and anti-Alzheimer(Acetylcholinesterase and butyrylcholinesterase inhibition assay) activities. Total polyphenol and flavonoid contents of OFIs were 17.40~23.11 μg garlic acid/mg Ex and 2.17~6.22 ug (+)-catechine/mg Ex, respectively. DPPH and ABTS radical scavenging activity of OFIs were 131.98~184.90 mg ascorbic acid(AA) eq/100 g and 63.60~101.83 mg AA eq/100 g, respectively. In the anti-diabetic and anti-Alzheimer activities, 70% ethanol extracts of OFI exhibited moderate inhibition activity, compared to control (acarbose and beberine). Total polyphenol and flavonoid contents, antioxidant, anti-diabetic, and anti-Alzheimer activities were no significant differences by season, respectively. Therefore, information on comparative biological evaluations of OFI may be a beneficial in exploring functional food and drug development.

To investigate the anti-diabetic activity of ethanol and aqueous peel and seed extracts obtained from three different grape species (Cambell Early, MBA, and Kyoho), alpha-glucosidase inhibitory activity was examined. All extracts showed anti-diabetic activity, especially aqueous extract exhibited inhibitory effect above 70%. Thus, we used aqueous extract to check the potential hypoglycemic effects in a streptozotocin (STZ)-induced diabetic mice model. The results showed that the blood glucose level of STZ-induced diabetic mice decreased drastically after 3 hr when the aqueous extract of Cambell Early seed was treated to the mice model. The aqueous extract of Kyoho seed lessened blood glucose level by 60%. Together, these data indicate that extracts of grape peel and seed (aqueous or ethanol) may have potential in improving hypoglycemic effects in the diabetic symptoms, suggesting that further investigation on biomarker expressions should be rewarding.