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

• SCG had higher total fiber and resistant starch content compared with coffee beans.
• SCG can be fermented by colon microbiota producing short-chain fatty acids.
• Human gut fermented-unabsorbed-SCG fraction suppress NO production.
• Hgf-NDSCG modulates IL-10, CCL-17, CXCL9, IL-1β, and IL-5 cytokines.
• SCG could protect the onset and/or progression of chronic inflammatory diseases.

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 (24 h) 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.