Daidzin (Daidzoside) is an isoflavone isolated from soya bean with anti-oxidant, anti-carcinogenic, and anti-atherosclerotic activities.

Daidzin, a glycoside of daidzein, increases the transcriptional activity of RARα and RARγ but does not bind to the RARs[1]. Daidzin does not inhibit human class Ⅰ, Ⅱ, or Ⅲ alcohol dehydrogenases, nor does it have any significant effect on biological systems that are known to be affected by other isoflavones. Daidzin inhibits human ALDH-I and ALDH-II in a concentration-dependent manner. Daidzin inhibits both ALDH-I and ALDH-II in an apparently competitive manner with Ki values of 40 nM and 20 μM, respectively, and it inhibits ALDH-I uncompetitively with respect to NAD+. The inhibition of ALDH-I by daidzin is reversible[3].

Daidzin has no effect on alcohol-metabolizing enzymes(i.e., ADH and ALDH) when given to rats intragastrically. Chronic daidzin administration exerts an effect on alcohol pharmacokinetics, although the effect is less pronounced than when the compound is administered concurrently with ethanol.The compound is shown to shorten sleep time if ethanol is given intragastrically, but not when given intraperitoneally, indicating absence of effect on ethanol elimination rate. Daidzin delays ethanol absorption and lessens alcohol intoxication. The compound is shown to suppress the levels of BAC(blood alcohol concentration) for the first 3 hr after alcohol ingestion in both fasted and fed rats. These effects of daidzin may in part be due to its antioxidant activity[2].

CV-1 cells are transfected with 100 ng ERE-Luc and 50 ng ER-RARα or ER-RARγ. Transfected cells are treated with the indicated isoflavone at 0.5, 1, 10, 50, and 100 μM for 24 h. The β-Gal activity is used to normalize luciferase activity.  (Only for Reference)