Health Beneficial Functions of Black Soybean Polyphenols
Black soybean, a soybean cultivar with a black pigment in its seed coat, has been used as food and traditional medicine in Asian countries. Black soybean is an attractive foodstuff for the prevention of lifestyle diseases. Soy foods contain various active ingredients, such as isoflavones, saponins, phytic acid, phenolic acids, lecithin, phytosterols, and omega-3 fatty acids. In addition to these ingredients, black soybean contains abundant polyphenols such as anthocyanins and flavan-3-ols in its seed coat. In this chapter, we have focused on black soybean polyphenols and have shown their health beneficial functions such as anti-obesity and anti-hyperglycemic activities through the activation of AMP-activated protein kinase and translocation of glucose transporter 4, respectively. We have also shown the function of black soybean polyphenols in modulating drug metabolism. Furthermore, we have also shown that potent antioxidant activity contributes to prevention of oxidative DNA damage, in addition to the induction potential of antioxidant enzymes. Moreover, we address the safety estimation of the black soybean polyphenols-rich food material including mutagenicity, DNA damage, and toxicity to animals.