Essential oil composition, antibacterial and antioxidant activity of the oil and various extracts of Ziziphora clinopodioides subsp rigida (Boiss.) RECH. f. from Iran

The chemical composition of the essential oil obtained from the aerial parts of Z, clinopodioides subsp. rigida (BOISS.) RECH. f. was analysed by GC and GC-MS. Thirty-one constituents accounting to 99.5% of the total oil were identified. Oxygenated monoterpenes (93.3%) were the predominant portion of the oil with pulegone (45.8%), piperitenone (17.4%),p-menth-3-en-8-ol (12.5%) and thymol (8.0%) as the main constituents. Antibacterial activity of the oil and its two main compounds and various extracts of plant were tested against seven Gram-(+) or Gram-(-) bacteria. It was found that the oil and MeOH extract (M) exhibited interesting antibacterial activity. The samples were also subjected to screening for their possible antioxidant activity by using 2,2diphenyl-1-picrazylhydrazyl (DPPH) assay. The free radical scavenging activity of MeOH extract (M) was superior to all other extracts (IC50=30.7 mu g/ml), while the oil was less effective.