Essential oil of Mentha suaveolens Ehrh., composition and antibacterial activity against bacterial fish pathogens.

In this study, it was determinated the essential oil of cultivated apple mint, Mentha suaveolens Ehrh. composition and in vitro antibacterial activity of against 11 fish pathogen bacteria including Gram-positive (Staphylococcus warneri, Staphylococcus sp., Lactococcus garvieae, Vagococus salmoninarum) and Gram-negative (Aeromonas hydrophila, Aeromonas sobria Aeromonas cavieae, Vibrio anguillarum, Pseudomonas aeroginosa, Yersinia ruckeri, Edwardsiella tarda) by using agar diffusion assay. The main component of M. suaveolence oil was obtained as piperitenone oxide. The essential oil exhibited strong inhibitory activity such as inhibition zone sizes: 30-50mm at 250-1000 µL mL-1 concentrations against V. anguillarum; 16-20mm at 31.25-125 µL mL-1 concentrations against P. aeroginosa; 15-18mm at 500-1000 µL mL-1 concentrations against A. sobria. However, it was found to be moderately effective against E. tarda (8-15 mm), Y. ruckeri (9-12mm), S. warneri (9-10mm), V. salmoninarum (9mm) and Staphylococcus sp. (8-9mm). The essential oil showed weak inhibitory activity against A. cavieae (5-8), A. hydrophila (6-7mm), L. garvieae (5-7mm). Thus, effect of essential oil of M. suaveolens on immune response and disease resistance against Vibrio anguillarum, A. sobria and P. aeroginosa should be investigated in vivo in cultured fish species in future studies.

Isolation and identification of chemical constituents from Origanum majorana and investigation of antiproliferative and antioxidant activities.

BACKGROUND: Origanum majorana L., belonging to the Lamiaceae family, has great potential and has been used as a folk medicine against asthma, indigestion, headache and rheumatism; in addition, the essential oils of this plant have been used widely in the food industry. Plant materials have been harvested from the Medicinal and Aromatic Plant Field of Gaziosmanpasa University. Air-dried plant materials were boiled in water, filtered, and the solvent part subsequently extracted with hexane and ethyl acetate. The chromatographic method was applied to the ethyl acetate extract to isolate bioactive secondary metabolites, the structures of which were elucidated by spectroscopic techniques: basically one-dimensional and two-dimensional nuclear magnetic resonance and quadrupole time-of-flight liquid chromatography. Antiproliferative and antioxidant activities of isolated secondary metabolites were determined. RESULTS: 5,6,3'-Trihydroxy-7,8,4'-trimethoxyflavone, hesperetin, hydroquinone, arbutin and rosmarinic acid were isolated from the water-soluble ethyl acetate extract of aerial parts of O. majorana. Antioxidant activities of isolated compounds and water-soluble ethyl acetate extract were investigated using assays of DPPH(•), ABTS(•+), reducing power and total phenolic content. Antiproliferative activities of the isolated compounds and plant extracts were investigated against C6 and HeLa cell lines using BrdU cell proliferation enzyme-linked immunosorbent assay and xCELLigence assay, respectively. Both hesperetin and hydroquinone were determined to have stronger antiproliferative activities against C6 and HeLa cells than the other isolated compounds and 5-fluorouracil. CONCLUSION: The results showed that the extract and isolated compounds exhibited significant antioxidant activities. Hence this plant has the potential to be a natural antioxidant in the food industry and an anticancer drug.

Antioxidant activity and chemical composition of Sideritis libanotica Labill. ssp. linearis (Bentham) Borm. (Lamiaceae).

Sideritis libanotica ssp. linearis was screened for the isolation of new natural antioxidant compounds. The antioxidant activity of flavones obtained from the methanol extract of the plant was evaluated in vitro using total antioxidant, reduction power and free radical scavenging activity. Results were compared with the positive controls of antioxidant standards (α-tocopherol and butylated hydroxytoluene). The results indicate that the flavones possess a higher antioxidant activity when compared to the other components in the plant. The lowest antioxidant activity was observed in fatty acids (FAs) and hydrocarbons. The FAs were methylated with MeOH and KOH and analysed by GC-MS. The structures of the isolated compounds were established based on spectroscopic evidence (NMR, GC-MS, HPLC, IR and UV). In this work, the isolated pure flavone (3'-O-methylhypolaetin 7-O-[6″'-O-acetyl-ß-D-allopyranosyl-(1 → 2)]-6″-O-acetyl-ß-D-glucopyranoside) was found to possess the highest antioxidant activity.

Evaluation of bioactivity of linalool-rich essential oils from Ocimum basilucum and Coriandrum sativum varieties.

Essential oils from Ocimum basilicum L. and Coriandrum sativum L. varieties originating from Turkey were investigated for their antimicrobial properties. The antimicrobial effects of the oil varieties were evaluated by the disc diffusion and minimum inhibitory concentration (MIC) methods against eight bacteria and three fungi. The compositions of the essential oils were analyzed and identified by GC and GC-MS. O. basilicum, C. sativum var. macrocarpum and var. microcarpum oils revealed the presence of linalool (54.4%), eugenol (9.6%), methyl eugenol (7.6%); linalool (78.8%), gamma-terpinene (6.0%), nerol acetate (3.5%); and linalool (90.6%), and nerol acetate (3.3%) as the major components, respectively. The oils exhibited antibacterial activity ranging from 1.25 to 10 microL disc(-1) against the test organisms with inhibition zones of 9.5-39.0 mm and minimal inhibitory concentrations values in the range 0.5- > or =1 microL/L. Linalool, eugenol, and methyl eugenol at 1.25 microL disc(-1) had antimicrobial effects on all microorganisms, giving inhibition zones ranging from 7 to 19 mm.