SYNTHESIS OF 3,4-CIS-[H-3]LEUCOCYANIDIN AND ENZYMATIC REDUCTION TO CATECHIN

A novel method is presented for the synthesis and purification of (+)-2,3-trans-3,4-cis-[4-3H]leucocyanidin. Soluble enzyme extracts from developing barley grains and leaves of the forage legume Onobrychis viciifolia (sainfoin) catalyzed the NAD(P)H-dependent reduction of (+)-2,3-trans-3,4-cis-[4-3H]leucocyanidin to (+)-]43H]catechin. NADPH was the preferred substrate. With extracts of barley the rate of reaction with 1 mM NADH was 20% of the rate found with NADPH. With extracts from both tissues there was a broad pH optimum around pH 6.6. © 1994 Academic Press, Inc. All rights reserved.