1-1-diphenyl-2-picrylhydrazyl and isoborneol

Chemical composition, antimicrobial and antioxidant activities of the essential oil of Ampelopsis megalophylla were evaluated in this research. GC-MS analysis of the essential oil revealed 42 compounds, representing 88.54% of the oil. The major compounds were borneol (10.81%), α-pinene (6.74%) and β-elemene (6.23%). The antimicrobial activity of the essential oil was evaluated against 13 micro-organisms using the disc diffusion and broth microdilution methods. Results demonstrated higher effects of this oil against Gram-positive bacteria than the other reference strains tested. The antioxidant effect of the essential oil was evaluated by using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,20-azinobis-3-ethylbenzthiazoline-6-sulfonate scavenging assays. The essential oil exhibited moderate antioxidant activity.

Topics: Ampelopsis; Anti-Bacterial Agents; Antioxidants; Bicyclic Monoterpenes; Biphenyl Compounds; Camphanes; Gas Chromatography-Mass Spectrometry; Gram-Positive Bacteria; Microbial Sensitivity Tests; Monoterpenes; Oils, Volatile; Picrates; Plant Leaves; Plant Oils; Sesquiterpenes

The essential oil, obtained by using a Clevenger distillation apparatus, and water-soluble (polar) and water-insoluble (nonpolar) subfractions of the methanol extract of Thymus pectinatus Fisch. et Mey. var. pectinatus were assayed for their antimicrobial and antioxidant properties. No (or slight) antimicrobial activity was observed when the subfractions were tested, whereas the essential oil showed strong antimicrobial activity against all microorganisms tested. Antioxidant activities of the polar subfraction and the essential oil were evaluated using 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, superoxide radical scavenging, and lipid peroxidation assays. The essential oil, in particular, and the polar subfraction of the methanol extract showed antioxidant activity. The essential oil was analyzed by GC/MS, and 24 compounds, representing 99.6% of the essential oil, were identified: thymol, gamma-terpinene, p-cymene, carvacrol, and borneol were the main components. An antimicrobial activity test carried out with fractions of the essential oil showed that the activity was mainly observed in those fractions containing thymol, in particular, and carvacrol. The activity was, therefore, attributed to the presence of these compounds. Other constituents of the essential oil, such as borneol, gamma-terpinene, and p-cymene, could be also taken into account for their possible synergistic or antagonistic effects. On the other hand, thymol and carvacrol were individually found to possess weaker antioxidant activity than the crude oil itself, indicating that other constituents of the essential oil may contribute to the antioxidant activity observed. In conclusion, the results presented here show that T. pectinatus essential oil could be considered as a natural antimicrobial and antioxidant source.

Topics: Anti-Bacterial Agents; Antioxidants; Bacteria; Biphenyl Compounds; Camphanes; Chemical Fractionation; Cyclohexane Monoterpenes; Cymenes; Free Radical Scavengers; Gas Chromatography-Mass Spectrometry; Lamiaceae; Lipid Peroxidation; Methanol; Monoterpenes; Oils, Volatile; Picrates; Plant Extracts; Plant Oils; Terpenes; Thymol