Medine Gulluce

Bio: Medine Gulluce is an academic researcher from Atatürk University. The author has contributed to research in topics: Essential oil & Mentha longifolia. The author has an hindex of 29, co-authored 142 publications receiving 5438 citations. Previous affiliations of Medine Gulluce include Yeditepe University.

Antimicrobial and antioxidant properties of the essential oils and methanol extract from Mentha longifolia L. ssp. longifolia

Abstract: This study was designed to evaluate antimicrobial and antioxidant activities of the essential oil and methanol extract from Mentha longifolia ssp. longifolia . The essential oil showed strong antimicrobial activity against all 30 microorganisms tested whereas the methanol extract almost remained inactive. In contrast, the extract showed much better activity than the essential oil in antioxidant activity assays employed, e.g. in the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid systems. In the former, the extract was able to reduce the stable free radical DPPH with an IC 50 of 57.4 μg/ml while that of the oils was 10 700 μg/ml. When compared to BHT, a synthetic antioxidant, both showed weaker antioxidative potential. Similarly, in β-carotene/linoleic acid assay, these samples were not effectively able to inhibit the linoleic acid oxidation; exhibiting only 24% and 36% inhibitions at 2 mg/ml, respectively; both were far below than that of BHT. Total phenolic constituent of the extract was 4.5 g/100 g as gallic acid equivalent. GC–MS analysis of the oil resulted in the identification of 45 constituents, cis -piperitone epoxide, pulegone and piperitenone oxide being the main components.

Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L.

Abstract: Aqueous and methanol extracts of the leaves of Juniperus oxycedrus were investigated for their in vitro antimicrobial properties. The plant was collected from Pelitli Village of Gebze, Kocaeli, in the Marmara region of Turkey. Juniperus oxycedrus is widely used as traditional folk medicine in Turkey for treatment of different infectious diseases. The antimicrobial activity of the extracts against 143 laboratory strains belonging to 56 bacterial species, and 31 isolates of 5 fungi species were evaluated based on the inhibition zone using the disc-diffusion assay, minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) values. The aqueous extract of J. oxycedrus had no antimicrobial effect against the test microorganisms whereas the methanol extract had inhibitory effects on the growth of 57 strains of 24 bacterial species in the genera of Acinetobacter, Bacillus, Brevundimonas, Brucella, Enterobacter, Escherichia, Micrococcus, Pseudomonas, Staphylococcus, and Xanthomonas. In addition 11 Candida albicans isolates at a concentration of 31.25-250 micro g/ml were also inhibited.

Biological activities of the essential oils and methanol extract of Origanum vulgare ssp. vulgare in the Eastern Anatolia region of Turkey

Abstract: The present study was conducted to evaluate the antimicrobial activities, antioxidant and properties of essential oils and methanol extracts of Origanum vulgare ssp. vulgare plants. The chemical composition of a hydrodistilled essential oil of O. vulgare ssp. vulgare was analyzed by a GC/MS system. A total 62 constituents were identified. Caryophyllene and spathulenol were found to be the main constituents, followed by germacrene-D and α-terpineol. Antioxidant activity was measured employing two methods namely, scavenging of free radical DPPH and the inhibition of linoleic acid oxidation by methanol extracts and the essential oil of O. vulgare ssp. vulgare . Antioxidant studies suggested that methanol extract behaved as a strong free radical scavenger providing IC 50 at only 9.9 μg/ml, whereas the oil showed weaker activity with IC 50 at 8.9 mg/ml. Total phenolic constituents based on gallic acid equivalents revealed the presence of total soluble phenolics in the extract as 220 μg/mg dry extract (22%, w/w) and, most probably, they are responsible for the radical scavenging activity of methanol extracts. Methanol extract was not effectively able to inhibit linoleic acid oxidation and only 32% inhibition was achieved at 2 mg/ml concentration, far below that of the positive control (butylated hyroxytoluene, BHT) at the same concentration. However, 2.2 mg/ml essential oil solutions provided 50% inhibition in the linoleic acid oxidation test system. The antimicrobial test results showed that the essential oil of O. vulgare ssp. vulgare had great potential of antimicrobial activity against all 10 bacteria, and 15 fungi and yeast species tested. In contrast, the methanol extract from aerial parts of O. vulgare plant showed no antimicrobial activity. The result may suggest that the essential oil O. vulgare ssp. vulgare possesses compounds with antimicrobial properties as well as antioxidant activity, and therefore can be used as a natural preservative ingredient in food and/or pharmaceutical industry.

In vitro antibacterial, antifungal, and antioxidant activities of the essential oil and methanol extracts of herbal parts and callus cultures of Satureja hortensis L.

Abstract: The present study was designated to evaluate the antimicrobial and antioxidant activities of the essential oil, obtained by using a Clevenger distillation apparatus, water soluble (polar) and water insoluble (nonpolar) subfractions of the methanol extracts from aerial parts of Satureja hortensis L plants, and methanol extract from calli established from the seeds using Gamborg's B5 basal media supplemented with indole-3-butyric acid (10 ppm), 6-benzylaminopurine (N(6)-benzyladenine) (10 ppm), and sucrose (25%) The antimicrobial test results showed that the essential oil of S hortensis had great potential antimicrobial activities against all 23 bacteria and 15 fungi and yeast species tested In contrast, the methanol extract from callus cultures and water soluble subfraction of the methanol extract did not show antimicrobial activities, but the nonpolar subfraction had antibacterial activity against only five out of 23 bacterial species, which were Bacillus subtilis, Enterococcus fecalis, Pseudomonas aeruginosa, Salmonella enteritidis, and Streptococcus pyogenes Antioxidant studies suggested that the polar subfractions of the methanol extract of intact plant and methanol extract of callus cultures were able to reduce the stable free radical 2,2-diphenyl-1-picrylhydrazyl to the yellow-colored diphenylpicrylhydrazine In this assay, the strongest effect was observed for the tissue culture extract, with an IC(50) value of 2376 +/- 080 microgram/mL, which could be compared with the synthetic antioxidant agent butylated hydroxytoluene On the other hand, linoleic acid oxidation was 95% inhibited in the presence of the essential oil while the inhibition was 90% with the chloroform subfraction of the intact plant The chemical composition of a hydrodistilled essential oil of S hortensis was analyzed by gas chromatography (GC)/flame ionization detection (FID) and a GC-mass spectrometry system A total 22 constituents representing 999% of the essential oil were identified by GC-FID analaysis Thymol (290%), carvacrol (265%), gamma-terpinene (226%), and p-cymene (93%) were the main components

The in vitro antimicrobial and antioxidant activities of the essential oils and methanol extracts of endemic Thymus spathulifolius

Abstract: The present study was conducted to evaluate the in vitro antimicrobial and antioxidant properties of essential oil and methanol extracts from a unique and endemic plant, Thymus spathulifolius (Hausskn. and Velen.). The antimicrobial test results showed that the essential oil of T. spathulifolius strongly inhibited the growth of test microorganisms studied, except for 4 fungi species while polar and non-polar subfractions of the methanol extract had moderate antibacterial, but not antifungal and anticandidal activity. The antioxidative potential of the samples was evaluated using two separate methods, inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β -carotene–linoleic acid systems. The polar subfraction of the methanol extract was able to reduce the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) with an IC 50 of 16.15 ± 0.5 μg/ml, which was lower than that of synthetic antioxidant, BHT, (19.8 ± 0.5 μg/ml). Inhibition values of linoleic acid oxidation were calculated as 92% and 89% for the oil and the polar subfraction, respectively. Gallic acid equivalent total phenolic constituent of the polar subfraction was 141.00 ± 0.90 μg/mg (14.1%, w/w). The chemical composition of a hydrodistilled essential oil of T. spathulifolius was analyzed by a GC and GC/MS system. A total of 28 constituents representing 99.2% of the oil were identified; thymol (36.5%), carvacrol (29.8%), p -cymene (10.0%) and γ -terpinene (6.3%) were the main components comprising 82.6% of the oil. Results presented here may suggest that the essential oil and extracts of T. spathulifolius possess antimicrobial and antioxidant properties, and therefore, they can be used as a natural preservative ingredient in food and/or pharmaceutical industry.

Biological effects of essential oils - A review

Abstract: Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, medicinal and cosmetic applications, especially nowadays in pharmaceutical, sanitary, cosmetic, agricultural and food industries. Because of the mode of extraction, mostly by distillation from aromatic plants, they contain a variety of volatile molecules such as terpenes and terpenoids, phenol-derived aromatic components and aliphatic components. In vitro physicochemical assays characterise most of them as antioxidants. However, recent work shows that in eukaryotic cells, essential oils can act as prooxidants affecting inner cell membranes and organelles such as mitochondria. Depending on type and concentration, they exhibit cytotoxic effects on living cells but are usually non-genotoxic. In some cases, changes in intracellular redox potential and mitochondrial dysfunction induced by essential oils can be associated with their capacity to exert antigenotoxic effects. These findings suggest that, at least in part, the encountered beneficial effects of essential oils are due to prooxidant effects on the cellular level.

Soil enzymes: Kuprevich, V. F. & Shcherbakova, T. A.: Translated from the Russian edition (1966), published by the Indian National Scientific Documentation Centre, New Delhi 1971. 392 pp., offset printing from type script, paper cover. Obtainable from U.S. Department of Commerce, National Technical Information Service, Springfield, Va. 22151

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DPPH antioxidant assay revisited

Abstract: Scavenging of DPPH free radical is the basis of a common antioxidant assay. A number of protocols have been followed for this assay resulting in variation in the results of different laboratories. We present a perspective of the protocols followed by different workers with incongruity in their results and recommend a standard procedure within the sensitivity range of spectrophotometry. Three common standard antioxidants viz. ascorbic acid, BHT and propyl gallate have been used in this study. The IC 50 values for ascorbic acid and propyl gallate were 11.8 μM and 4.4 μM in methanol and 11.5 μM and 4.7 μM in buffered methanol as reaction medium, respectively. The free radical scavenging by BHT was markedly influenced by the reaction medium. The IC 50 values were 60.0 μM and 9.7 μM when the reaction was done in methanol and buffered methanol, respectively.