Effect of Drying Conditions on Antioxidant and Anti-Inflammatory Activities of Leaf and Calyx Extracts from Capsicum annuum By-Products

The effective utilization of agro-food by-products has gained increasing attention as a strategy to reduce food loss and promote sustainable resource management. This study evaluated the antioxidant and anti-inflammatory activities of extracts obtained from leaf and calyx by-products of Capsicum annuum according to tissue type and drying conditions. Samples were dried at 25 °C or 60 °C and extracted with 70% ethanol, yielding extracts designated as L25, L60, C25, and C60. Total polyphenol and flavonoid contents were determined using the Folin–Ciocalteu and aluminum nitrate methods, respectively. Antioxidant activities were evaluated using DPPH, ABTS, FRAP, and SOD-like activity assays. Anti-inflammatory activity was assessed by measuring nitric oxide (NO) production and the secretion of pro-inflammatory cytokines (IL-6 and TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Leaf-derived extracts exhibited higher antioxidant activity than calyx-derived extracts. In addition, samples dried at 25 °C showed higher antioxidant activity than those dried at 60 °C, suggesting that lower drying temperatures better preserve bioactive compounds. Among the samples, L25 showed the highest antioxidant capacity and SOD-like activity. The extracts also inhibited NO production and reduced IL-6 and TNF-α secretion without significant cytotoxicity. These results suggest that by-products of C. annuum, particularly leaf tissues dried at lower temperatures, may serve as potential natural sources of antioxidant and anti-inflammatory compounds for functional food applications.