Antioxidant and radical scavenging effect of different parts of four Turkish Juniperus species

The comparative antioxidant potential of J. drupacea, J. oxycedrus, J. foetidissima and J. excelsa leaf and fruit water extracts were studied. Their antioxidant activities were evaluated by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) method and non-enzymatic rat hepatic microsomal lipid peroxidation method. Various antioxidant activities were compared with standard antioxidant vitamin E (α-tocopherol). Fruit and leaf extracts of J. Durapacea (IC₅₀; 24µg/ml; IC₅₀; 35µg/ml, respectively) and J. foetidissima (IC₅₀; 33.5µg/ml; IC₅₀; 26µg/ml, respectively) were found to be a good scavenger of DPPH radical when compared to vitamin E (IC₅₀; 13µg/ml). J.oxycedrus and J. excelsa fruit extracts exhibited the weakest effect on DPPH radical with IC₅₀ values of 115 and 104µg/ml, respectively, compared with α-tocopherol.

Almost all tested extracts exhibited very strong antioxidant properties when compared to vitamin E (α-tocopherol) with percent inhibition of 84–97% in the TBA assays at the 0.25 and 0.5mg/ml concentrations. TBA assay results showed that J. drupacea leaf (95%) and fruit extracts have the strongest anti-lipid peroxidation activity (91–96%) at a dose of 0.25–0.5mg/ml, respectively. J. oxycedrus leaf extract also exhibited strong anti-lipid peroxidation effect with percent inhibition of 88–97% while J. oxycedrus fruit extract showed moderate activity with percent inhibition of 48–65% in the TBA assay and DPPH methods. The results showed that J. drupacea and J. foetidissima extracts have higher antioxidant capacities than J.oxycedrus and J. excelsa fruit extracts.