Bioaccessibility and anti-inflammatory activity in Caco-2 cells of phytochemicals from industrial by-products of coffee (Coffea arabica L.)

Coffee by-products are rich in nutrients and bioactive compounds in free soluble form and bound to cell wall components. These compounds undergo chemical changes during gastrointestinal digestion, affecting their bioaccessibility and bioactivity. This study is the first to investigate coffee by-products from industrial wet processing to evaluate the impact of simulated gastrointestinal digestion on their phytochemical composition and subsequent anti-inflammatory activity in Caco-2 cells. Digestion significantly reduced the stability and solubility of main compounds; however, digested bioaccessible by-products still exhibited anti-inflammatory properties, reducing IL-6, IL-8, and TNF-α levels. Correlation analysis identified rutin, quercetin-3-glycoside, caffeine and 5-caffeoylquinic acid as strongly linked to cytokine suppression, suggesting key roles and possible synergies. These results highlight the potential of coffee by-products as functional ingredients targeting intestinal inflammation. Future work should confirm in vivo efficacy, optimize extraction at scale, and address regulatory requirements to support industrial application and promote circular economy benefits. • 43 phytochemicals found in extracts from coffee by-products industrial processing. • Caffeine and chlorogenic acid were the main compound in coffee husk and mucilage. • Samples had high bioaccessibility post in vitro gastrointestinal digestion. • Digested coffee by-products reduced the secretion of IL-6, IL-8 and TNF-α cytokines.