Anthocyans, comprising anthocyanins and their aglycones (anthocyanidins), are a class of flavonoids that are widely distributed in fruits, vegetables and beverages. In this study, we investigated the effects of cyanidin (anthocyanidin), and cyanidin 3-glucoside and cyanidin 3-rutinoside (anthocyanins) on the transport of rhodamine 123, a fluorescent cationic dye often used as a substrate for P-glycoprotein, in human renal proximal tubular cell line HK-2. The steady-state accumulation of rhodamine 123 in HK-2 cells significantly increased in the presence of cyanidin as well as verapamil, a typical P-glycoprotein inhibitor. On the other hand, cyanidin 3-glucoside and cyanidin 3-rutinoside, but not cyanidin, significantly decreased the initial uptake of rhodamine 123 via an influx transporter that is inhibited by cimetidine, a pan-inhibitor of organic cation transporters. In contrast to co-incubation with cyanidin 3-glucoside and cyanidin 3-rutinoside, pre-incubation with the two anthocyanins had no effect on the initial uptake of rhodamine 123 in HK-2 cells. These findings suggest that cyanidin, but not its glycosides, inhibits P-glycoprotein-mediated efflux of rhodamine 123, while the two anthocyanins, but not their aglycone, decrease the influx transporter that is involved in the initial uptake of rhodamine 123 in HK-2 cells.
View Full Article