Inhibitory effect of anthocyanins and colored rice on diabetic cataract formation in the rat lenses

摘要

In the course of our screening for diabetic cataract inhibitors from edible plants using a rat lens organ culture system under 15 mM xylose condition, five anthocyanin monomers isolated from the extract of grape skins showed the inhibitory activities for lens opacity. Malvidin 3-glucoside and delphinidin 3-glucoside showed stronger inhibitory activities than cyanidin 3-glucoside (C3G); petunidin 3-glucoside (P3G) and peonidin 3-glucoside in this assay system.Concerning a continuous intake of anthocyanins from daily foods, colored rice is one of the good candidates among the Asian countries. Red rice and black rice have been eaten traditionally in China, Japan, India, etc. Thus, we started to collect strains of colored rice from the Asian countries; finally, 48 stains were collected. After extended screening of the collected strains of colored rice, two excellent strains, asamurasaki-2 (AS2, Japanese black rice) and chikushi-akamochi-2 (CH2; Japanese red rice), were selected as potential inhibitory strains for the rat lens opacity. The content of anthocyanins (mainly C3G) and the other important polyphenols (ferulic acid (FA), caffeic acid (CA) and protocatechuic acid (PA)) of these strains were quantified.