Food Science and Nutrition Group

Singapore, Singapore

Food Science and Nutrition Group

Singapore, Singapore
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Tsen S.Y.,Food Science and Nutrition Group | Tsen S.Y.,Center for Functional Food and Human Nutrition | Tan X.Y.,Food Science and Nutrition Group | Tan Y.M.,Food Science and Nutrition Group | And 3 more authors.
Journal of Medicinal Food | Year: 2016

The effects of bioavailability and metabolic transformation on the biological activities of daidzein are relatively unknown. The effects of daidzein, dihydrodaidzein, and equol at physiologically relevant concentrations on the production of leukotriene B4 and F2-isoprostanes, and myeloperoxidase enzyme activity in freshly isolated human neutrophils were examined. Equol, at physiological concentrations, inhibited leukotriene B4 production (IC50-200 nmol/L) in human neutrophils significantly more than daidzein and dihydrodaidzein (IC50 values >1000 nmol/L). Daidzein, dihydrodaidzein, and equol did not affect the enzymatic hydrolysis of leukotriene A4 to leukotriene B4, suggesting that they exerted their inhibitory effects on the 5-lipoxygenase activity. Daidzein (IC50 = 600 nmol/L) protected against free radical peroxidation of arachidonic acid significantly more than did equol and dihydrodaidzein (IC50 values >1000 nmol/L). Equol also showed significantly greater inhibition of myeloperoxidase activity (IC50 = 450 nmol/L) when compared to daidzein and dihydrodaidzein. Equol accumulated within the human neutrophils at significantly higher concentrations than daidzein and dihydrodaidzein after incubation with the three compounds at physiologically relevant concentrations. Neutrophils were able to accumulate intracellular daidzein, dihydrodaidzein, and equol up to a concentration of ∼600 nmol/L. Our results provide in vitro evidence that the biological activities of daidzein are profoundly influenced by bioavailability and metabolic transformation. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2016.


Tsen S.Y.,Food Science and Nutrition Group | Siew J.,Food Science and Nutrition Group | Lau E.K.L.,Food Science and Nutrition Group | Afiqah Bte Roslee F.,Food Science and Nutrition Group | And 2 more authors.
Dairy Science and Technology | Year: 2014

Cow's milk contains bioactive secondary phenolic compounds that are formed by bovine's gut bacterial flora from plant phenolic compounds. Equol, a metabolite of daidzein, is one such secondary compounds of biological interest. The potential of phenolic compounds in milk as dietary antioxidants and their distribution within the milk matrix were examined. The equol concentrations, total phenolic contents, and antioxidant activity (Trolox equivalent antioxidant capacity and inhibition of F2-isoprostanes formation by human neutrophils in vitro) were measured and compared in commercial cow's milk of varying lipid contents. The Trolox equivalent antioxidant capacity and ability to inhibit F2-isoprostanes formation in vitro increased with the concentrations of phenolic compounds and equol in the milk. Equol and total phenolic compound concentrations correlated positively with the milk lipid concentrations. Separate experiments using homogenized and non-homogenized milk showed that dairy equol and phenolic compounds distributed to larger extent in the lipid fraction than in the aqueous fraction of cow's milk. Our results showed that cow's milk may serve as a dietary source of unique phenolic compounds, such as equol. Skimming of cow's milk may reduce the original amount of equol and phenolic compounds and thereby diminishes the overall nutritive value and functional properties of cow's milk. © 2014 INRA and Springer-Verlag France.

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