Evaluation of Antitumor Activity of Hesperetin-Loaded Nanoparticles Against DMBA-Induced Oral Carcinogenesis Based on Tissue Autofluorescence Spectroscopy and Multivariate Analysis.

The present study is designed to understand the nature of endogenous fluorophores and cellular metabolism that occur in the experimental oral carcinogenesis and to assess their feasibility for antitumor efficacy of hesperetin-loaded nanoparticles (HETNPs) in comparison with native hesperetin (HET) against 7,12-dimethyl benz(a) anthracene (DMBA)-induced oral carcinogenesis using fluorescence spectroscopy. The fluorescence emission spectra of the control and the experimental buccal mucosa are recorded at an excitation wavelength of 320 nm with an emission ranging from 350 to 550 nm. The results show that there is a reduced contribution from the emission of collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), in DMBA-induced tumor tissues as compared with the control tissues. Furthermore, there was significant decrease in the optical redox ratio [(FAD/ (NADH + FAD)] is observed in DMBA-induced tumor tissues, which indicates an increased metabolic activity when compared to the control tissues. Oral administration of HET and its nanoparticulates restored the status of endogenous fluorophores emission and would have a higher redox ratio in the buccal mucosa of DMBA painted animals. Taken together, the treatment of nanoparticulate hesperetin was found to be more effective than native hesperetin in improving the status of endogenous fluorophores to a near normal range in DMBA-induced hamster buccal pouch carcinogenesis. The results of this study raise the important possibility that fluorescence spectroscopy in conjunction with PC-LDA has tremendous potential for monitor or potentially predict response to therapy.