Valorization of Solanum melongena L. crop by-products: Phenolic composition and in vitro antioxidant, antidiabetic, anti-inflammatory, cytotoxic, and antimicrobial properties

Abstract

This study explored the valorization of post-harvest eggplant aerial parts as a sustainable source of value-added ingredients by investigating their phenolic composition and in vitro bioactive properties. HPLC-DAD-ESI/MSⁿ analysis identified chlorogenic acid derivatives as the predominant phenolic compounds (53 % of the phenolic fraction), followed by O-glycosylated kaempferol and quercetin. The extract displayed antioxidant activity in physiologically relevant cell-based assays and significant α-glucosidase inhibitory capacity that far exceeded that of the standard drug acarbose. It also inhibited the formation of advanced glycation end-products (AGEs), suggesting its potential to mitigate diabetes-related complications. Furthermore, the extract showed a modest pancreatic lipase inhibitory effect and capacity to suppress interleukin 6 production. Selective cytotoxicity against human gastric and colon adenocarcinoma cell lines and strong antimicrobial activity against foodborne pathogens were observed. Given the growing demand for natural alternatives to synthetic drugs, these findings position eggplant crop biomass as a promising, sustainable source of active compounds with potential applications in food, nutraceutical, and pharmaceutical formulations for managing type 2 diabetes and other oxidative stress-mediated conditions. This study not only contributes to the valorization of agricultural waste but also expands the research on by-products of Solanaceae crops, offering a pathway for sustainable resource utilization.