Phenolic profile and anti-inflammatory activity of four Moroccan date (Phoenix dactylifera L.) seed varieties

Date (<i>Phoenix dactylifera</i> L.) seeds are seen as good drug to cure rheumatoid arthritis and asthma in Moroccan traditional medicine. The present research aimed to study the anti-inflammatory effect, of methanol extract of different date seed varieties using membrane stabilizing effect, nitric oxide radical scavenging activity, inhibition of protein denaturation, carrageenan-induced paw edema and croton oil induced ear edema. The polyphenolic profile was examined using HPLC-DAD. Rutin, quercetin, <i>p</i>-coumaric and caffeic acids were the main among the analysed phenolic compounds. Concerning the anti-inflammatory activity, the analysed date seed were significantly effective in scavenging nitric oxide free radical, in stabilisation of erythrocyte membrane and possessed a high anti denaturation effect. In agreement with this finding, date seed exhibited a profound ability to reduce paw and ear swelling induced by carrageenan and croton oil respectively. The biochemical parameters showed that date seed are able to reduce the erythrocyte sedimentation rate (ERS) and C-reactive protein (CRP) concentration in rats used in Carrageenan-induced paw edema model. The predominant phenolic compounds are the potential candidates that drive these activities and the differences observed among varieties are related to their chemical composition. These data suggest that date seeds can be explored as a therapeutic agent for the treatment of inflammatory diseases.