Catechin-Albumin Conjugates: Enhanced Antioxidant Capacity and Anticancer Effects.

(+)-Catechin conjugated with human serum albumin (CT-HSA) was prepared and evaluated as a drug carrier bearing anticancer effects. It was found that 2.4 mol of CT was conjugate to 1 mol HSA. The CT-HSA has an antioxidant capacity of about 3.3 times the amount of CT in the conjugate. Intracellular incorporation of the CT-HSA was analyzed by fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM) measurements using fluorescein isothiocyanate (FITC)-labelled CT-HSA. The results indicated that the FITC-labelled CT-HSA was incorporated into HeLa cells in a concentration-dependent manner. The CT-HSA enhanced the binding of anticancer drugs (5-fluorouracil (5-Fu) and mitomycin C (MMC)) comparing with HSA, and the CT-HSA mixed with 5-Fu or MMC decreased significantly the HeLa cell viability as compared with the same concentration of each drug. In addition, intracellular reactive oxygen species (ROS) scavenging by the CT-HSA is likely to affect the anticancer effects. Thus, the CT-HSA enhanced anticancer drug efficacy in relation to controlling ROS-scavenging ability.