A novel target and biomarker benzothiazolyl–naphthalimide probes for precise and selective detection of serum albumin and anticancer activity

Abstract

N-Benzothiazolyl-1,8-naphthalimide based fluorescent probes were designed and synthesized for selective detection of human serum albumin (HSA) and bovine serum albumin (BSA) among various bioanalytes and further studied for their in vitro anti-proliferative activity against 60 human cancer cell lines. Binding interactions of naphthalimide derivative 2-(benzo[d]thiazol-2-yl)-6-(4-methoxyphenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione bearing an electron-donating group (8) and 2-(benzo[d]thiazol-2-yl)-6-(2-flourophenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione having an electron-withdrawing group (12) with HSA and BSA were explored by spectroscopic as well as molecular modeling techniques. Amongst these two derivatives, probe 12 showed better binding affinity with human serum albumin and bovine serum albumin as compared to 8 and the limit of detection for 12 toward HSA was found to be 4.3 μM. Moreover, compound 12 with fluoro positioned at the phenyl ring displayed potent cytotoxic activity over other derivatives. Thus, the effects of both substituent and position account for the binding interactions of the compounds with serum albumin. These fluorescent probes can be used effectively for the quantification of HSA in clinical diagnosis.