Abstract
The total tannin, flavonoid and phenolic contents of R. frangula leaves were determined by colorimetric assay. The antioxidant and antibacterial activities of solvent extracts were investigated using various tests. The anti-PLA2 properties of these extracts were evaluated by measuring their inhibition potency on the human and dromedary pro-inflammatory phospholipase A2-IIA. The data showed that the water extract exhibited the highest amount of tannin compounds, whereas the total phenolic and flavonoid contents were highest in the methanol fraction. The same fraction was the most effective at the minimum inhibitory concentration against all strains tested and exhibited an antioxidant activity. In contrast, the water extract showed the best anti-PLA2-IIA activity, and no effect was recorded on the digestive DrG-IB. The results indicated a strong correlation between the antioxidant capacity, the total phenolic and flavonoid contents. However, no correlation was observed with the inhibitory effect against PLA2, suggesting that the anti-PLA2 molecules were tannin compounds.