Food-Grade Liposomal Encapsulation Enhances Cellular Delivery and Intracellular Antioxidant Function of Sugarcane Bagasse-Derived p-Coumaric Acid.

Abstract

Sugarcane bagasse is an abundant agricultural by-product containing bioactive phenolic compounds such as p-coumaric acid (CA), although their practical utilization is often limited by poor bioavailability. In this study, food-grade liposomes encapsulating purified CA (LCA) and bagasse-derived phenolic extract (LBC) were prepared to investigate whether liposomal delivery enhances intracellular antioxidant function. The physicochemical properties of the liposomes, including particle size, zeta potential, membrane morphology, and encapsulation efficiency, were characterized using dynamic light scattering, confocal laser scanning microscopy, Fourier transform infrared spectroscopy, and HPLC/MS/MS analysis. Both LCA and LBC formed stable nanosized vesicles (approximately 70-125 nm) with high encapsulation efficiencies exceeding 70 %. Optimization of the ultrasonication process substantially reduced particle size and improved particle uniformity compared with our previous formulation, producing liposomes suitable for cellular evaluation. Cellular antioxidant activity (CAA) assays using HepG2 cells demonstrated that both LCA and LBC exhibited greater intracellular antioxidant activity than their corresponding non-encapsulated samples under both AAPH- and H2O2-induced oxidative stress conditions. Liposomal encapsulation also modified cellular responses at higher concentrations, consistent with improved intracellular delivery of encapsulated phenolic compounds. These findings indicate that food-grade liposomal encapsulation effectively enhances the intracellular functionality of both purified CA and complex bagasse-derived phenolic extracts by improving cellular delivery. This study provides new evidence that physicochemically optimized food-grade liposomes can enhance the intracellular functionality of phenolic compounds and supports their potential as practical delivery systems for sustainable functional food ingredients derived from agricultural by-products.