Anti-inflammatory properties and phenolic profile of six Moroccan date fruit (Phoenix dactylifera L.) varieties

Date fruit (Phoenix dactylifera) is widely used in Moroccan pharmacopoeia to treat inflammation and other diseases. For this purpose, six date fruit varieties (Boufgous, Bouskri, Bousrdon, Bousthammi, Jihl, and Majhoul) were assessed for their phenolics profile and anti-inflammatory activity. Total phenolic and flavonoid contents of these extracts were measured by the high-performance liquid chromatography (HPLC). Protein denaturation was assessed employing bovine serum albumin. Edema formation was induced in rat's right hind paw and mice's right ear using carrageenan and croton oil, respectively. Membrane stabilizing activity was estimated by the prevention of hypotonicity induced-erythrocyte membrane damage. The results showed that Gallic, Ferulic and Caffeic acids and Rutin were the most dominant among the analyzed polyphenolic compounds. With regard to anti-inflammatory activity, Bousrdoun showed highest NO scavenging ability (IC50 = 531.34 µg/mL), highest protein denaturation inhibition (IC50 = 408.64 µg/mL) as well as highest membrane stabilizing effect (IC50 = 483.61 µg/mL). However, Jihl exhibited highest reduction of ear edema (74%), while both Jihl and Bousrdoun exhibited similar and highest paw oedema (40.35%). Our findings indicate that among the investigated date varieties, Jihl and Bousrdoun are found to be the most active anti-inflammatory compounds. The difference in activities seems to be related to the variations in the phenolic and flavonoids content between date varieties.