Polyphenols content and antioxidant power of fruits and leaves of Juniperus phoenicea L. From Tounfite (Morocco)

The natural antioxidants have attracted considerable attention of researchers because of their beneficial roles in human health. In the framework of the development of new antioxidants from natural sources, we are interested in this work in studying the phenolic compounds and evaluating the antioxidant properties of Juniperus phoenicea L. leaves and fruits collected in the mountains of Eastern High-Atlas (Tounfite). The phytochemical screening has allowed highlighting the existence of polyphenols, tannins, flavonoids, sterols and triterpenes, and oses and holosides in both studied samples. Mucilages are also present in these samples but in small quantities, while alkaloids and saponins are entirely absent. Extracts from leaves and fruits have been obtained by different extraction solvents: water, methanol, chloroform, ethyl acetate and n-butanol. The contents of total phenols and flavonoids were evaluated using gallic acid and quercetin as standard respectively. The ethyl acetate extracts of the leaves and fruits contain high levels of total phenolic estimated 2,91mg/g and 5,35mg/g equivalent of gallic acid (GAE) respectively. As for the flavonoid content, the ethyl acetate extracts have also reached the increased levels 11,82mg/g and 2,66mg/g equivalent of quercetin (QE). The antioxidant activities by DPPH test were quantified by spectrophotometry; the results showed that the ethyl acetate extracts from the leaves and fruits exhibit an antioxidant activity with inhibitory concentrations 50% (IC 50 ) of 94,4μg/ml and 185,83μg/ml respectively compared to that of vitamin C (47,76μg/ml). The antioxidant test allowed concluding that the leaves and fruits have a strong anti-radical activity that was assumed to be related closely to the content of polyphenols, which are generally very good antioxidants and that the leaves show a higher activity than fruits.