Nutritional spices from Cameroon inhibit inflammatory markers from human gastric epithelial cells

Several Cameroonian herbs/spices are traditionally used to remedy certain diseases. In this context different studies have demonstrated health benefits of Cameroonian spices, including anti-microbial and antioxidant properties, whereas their anti-inflammatory activity at gastric level has never previously been reported.

The present work chemically characterizes and investigates the anti-inflammatory effect of hydro-alcoholic extracts of eleven Cameroonian spices at the gastric level, focusing on Nuclear Factor (NF)-κB pathway.

Hydro-ethanolic extracts were prepared and characterized by HPLC-DAD and GC/MS analysis, then screened for their ability to inhibit tumor necrosis factor (TNF)α-induced IL-8 and IL-6 release, in human gastric epithelial cells (GES-1 and AGS). The activity of the extracts on NF-κB driven transcription was also evaluated.

After preliminary screening, six spices (Xylopia aethiopica, Xylopia parviflora, Tetrapleura tetraptera, Dichrostachys glomerata Aframomum melegueta and Aframomum citratum) were chosen among eleven plants for in-depth studies. The selected extracts reduced in a concentration-dependent fashion both the cytokines release (IC₅₀ between 0.19 µg/mL and 20 µg/mL) and NF-κB driven transcription (IC₅₀ between 0.33 µg/mL and 20 µg/mL). Chemical analysis suggested that their secondary metabolites (androstenone, chlorogenic acid, pimaric acid, catechin, caffeic acid and its derivatives, 4ʹ,5,7-trihydroxyflavanone, gingerol, shogaol, paradol and gallotannins) could potentially justify the biological properties observed.

Results obtained from this study showed that six extracts reduced inflammatory markers by impairing NF-κB signalling at the gastric level, justifying, at least in part, the Cameroonian traditional use of these spices. However, other molecular mechanisms cannot be excluded, and further studies are needed to better clarify their biological activities.