068 | In vitro modulation of inflammatory mediators by eggplant peel extracts from two cultivar

Alessandra Armeli, Desirèe Bonfiglio, Serena Munaò, Giovanna Calabrese | Department of Chemical, Biological, Pharmaceutical and Environmental Sciences ChiBioFarAm, University of Messina, Italy.

Abstract

Cellular stress and inflammation are tightly interconnected processes that, when dysregulated, contribute to the onset and progression of chronic degenerative diseases. Plant‑derived phytochemicals, particularly phenolic compounds, are increasingly investigated for their ability to modulate oxidative and inflammatory pathways. Eggplant (Solanum melongena L.) peels represent a rich source of anthocyanins, flavonoids, and phenolic acids, yet cultivar‑dependent differences in their biological activity remain poorly defined. This study investigated the anti‑inflammatory and cytoprotective potential of eggplant peel extracts from two cultivars (‘Black’ and ‘Violet’) using an in vitro inflammatory model based on murine macrophages (RAW 264.7) exposed to LPS‑induced stress. To induce inflammatory activation, cells were stimulated with LPS and co‑treated with eggplant peel extracts (50–100 μg/mL) for 1, 3, and 6 days. Cell viability, nitric oxide (NO) release, and the expression of key inflammatory markers (iNOS, COX‑2, IL‑1β, IL‑6) were evaluated through MTT assay, Griess assay, qRT‑PCR, immunocytochemistry. Our findings showed good tolerability for both peel extracts and demonstrated significant cytoprotective effects, effectively reducing LPS‑induced cytotoxicity. Both cultivars markedly attenuated NO release, with distinct temporal patterns: the ‘Black’ peel extract induced a rapid inhibitory response, restoring physiological NO levels by day 3, whereas the ‘Violet’ peel extract displayed a slower but progressive reduction peaking at day 6. Molecular analyses confirmed a consistent downregulation of pro‑inflammatory mediators, supporting a broad modulatory effect on stress‑related pathways. Such differences in activity could be explained by the distinct phenolic composition and antioxidant capacity of each cultivar, supporting the presence of unique phytochemical signatures influencing their anti‑inflammatory potential. Overall, these findings highlight the potential of eggplant peel extracts as natural modulators of inflammation and support the valorization of agricultural by‑products as promising sources of bioactive compounds. Further studies in more complex models will be necessary to validate these preliminary observations and elucidate the underlying molecular mechanisms.