Spent coffee grounds, an innovative source of colonic fermentable compounds, inhibit inflammatory mediators in vitro

Abstract

Spent coffee grounds (SCG), rich in dietary fiber can be fermented by colon microbiota producing short-chain fatty acids (SCFAs) with the ability to prevent inflammation. We investigated SCG anti-inflammatory effects by evaluating its composition, phenolic compounds, and fermentability by the human gut flora, SCFAs production, nitric oxide and cytokine expression of the human gut fermented-unabsorbed-SCG (hgf-NDSCG) fraction in LPS-stimulated RAW 264.7 macrophages. SCG had higher total fiber content compared with coffee beans. Roasting level/intensity reduced total phenolic contents of SCG that influenced its colonic fermentation. Medium roasted hgf-NDSCG produced elevated SCFAs (61:22:17, acetate, propionate and butyrate) after prolonged (24h) fermentation, suppressed NO production (55%) in macrophages primarily by modulating IL-10, CCL-17, CXCL9, IL-1β, and IL-5 cytokines. SCG exerts anti-inflammatory activity, mediated by SCFAs production from its dietary fiber, by reducing the release of inflammatory mediators, providing the basis for SCG use in the control/regulation of inflammatory disorders. The results support the use of SGC in the food industry as dietary fiber source with health benefits.

Keywords: Acetic acid (PubChem CID: 176); Butyric acid (PubChem CID: 264); Caffeic acid (PubChem CID: 689043); Caffeine (PubChem CID: 2519); Catechin (PubChem CID: 9064); Chlorogenic acid (PubChem CID: 1794427); Cytokines; Gallic acid (PubChem CID: 370); In vitro colonic fermentation; In vitro gastrointestinal digestion; Inflammation; Nitric oxide; Nitric oxide (PubChem CID: 145068); Propionic acid (PubChem CID: 1032); Rutin (PubChem CID: 5280805); Spent coffee grounds.