Antioxidant and Antimicrobial Activities of Extracts from Some Selected Mediterranean Plant Species

Merve Deniz Kose, Oguz Bayraktar, Ali Bora Balta

In this study, in vitro antioxidant and antimicrobial activities of the plant extracts of four different plant species were evaluated. These plants are; Olea europaea (Olive leaf), Liquidambar orientalis (Turkish sweetgum), Ziziphus jujuba (Lotus) and Juniperus communis (Juniper) which are common in Mediterranean region and used in various application, especially for therapeutic purposes. The most efficient extraction yield was obtained for Liquidambar orientalis as 24.7 %, and followed with Ziziphus jujuba and Olea europaea. The extracts of Liquidambar orientalis exhibited the highest phenol content as 0.372 mgGAEq/g sample. Antioxidant activities of the extracts ranged between 8.009 and 0.527 TEAC (mmol/g sample). Extracts of Liquidambar orientalis had the highest antioxidant capacity with 8.009 TEAC (mmol/g sample). The antimicrobial activities of plant extracts were evaluated by using both disc diffusion and minimum inhibition concentration assays. Disc diffusion results were obtained for each plant extracts. The diameter of inhibition zones ranged between 20.5 and 7.8 mm. The extracts of Liquidambar orientalis had the highest inhibition activity with 20.5 and 19.2 mm inhibition zones against Pseudomonas aeruginosa and Escherichia coli respectively. The extract of Olea europaea had second highest antimicrobial activity against E.coli with a inhibition zone diameter of 13.6 mm. Both extracts of Ziziphus jujuba and Juniperus communis showed approximately the same inhibition activity. The minimum inhibition concentration (MIC) values of plant extracts ranged between 0.4 and 100 mg/ml. Liquidambar orientalis extract had the lowest MIC values against Staphylococcus aureus and Staphylococcus epidermidis, Bacillus subtilis. The extract of Juniperus communis had second highest antimicrobial activity against S.epidermidis, S.aureus and B.subtilis with minimum inhibition concentration value of 3.125 mg/ml.