Original Articles: 2012 Vol: 4 Issue: 8
Study of eight medicinal plants for antioxidant activities
There is now an expansion of interest in phytochemicals as a new source of natural antioxidants to be used in foods and pharmaceutical preparations to substitute synthetic antioxidants, which are being restricted due to their potential health risks and toxicity. Eight Libyan medicinal plants belonging to different families were extracted successively with three solvents of different polarities using microwave technique. The antioxidant activity of these plant extracts were evaluated using 2,2, Diphenyl-1-picryhydrazyl (DPPH) radical scavenging method. Among the twenty four crude extracts, six showed strong antioxidant activity (IC50 ranging between 4.55 to 21.55 μg/ml), six of the extracts exhibited moderate antioxidant activity (IC50 values ranged between 40.7 to 94.4 μg/ml), and four crude extracts exhibited weak antioxidant activity (IC50 more than 200 μg/ml). The IC50 values of quercetin and ascorbic acid, used as standards in this assay were found to be 3.35 and 15.35 μg/ml, respectively. The antioxidants that are present in the eight Libyan medicinal plants studied in this paper could be used to inhibit or prevent the deleterious consequences of oxidative stress. The antioxidant effect could be related to the free radical scavengers like polyphenols, flavonoids and phenolic compounds.