Erol Dönmez

ANTIMICROBIAL AND ANTIOXIDATIVE ACTIVITIES OF THE ESSENTIAL OILS AND METHANOL EXTRACTS OF SALVIA CRYPTANTHA (MONTBRET ET AUCHER EX BENTH.) AND SALVIA MULTICAULIS (VAHL)

Abstract The essential oils and methanolic extracts of Salvia cryptantha and Salvia multicaulis were examined for their potential antimicrobial and radical scavenging activities. No, or slight, activity was observed when the polar and non-polar subfractions of the extracts were tested, whereas essential oils exhibited antimicrobial activity. The essential oils isolated from S. cryptantha and S. multicaulis were analysed by GC–MS and 53 and 47 constituents were identified, respectively. Antioxidant activities of the polar subfraction and the essential oil were examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical-scavenging and lipid peroxidation assays. The essential oils, in particular, and the non-polar subfractions of methanol extracts, showed antioxidant activity. In conclusion, the results indicate that the oils of S. cryptantha and S. multicaulis have the capacity to scavenge free radicals and to inhibit the growth of pathogenic microorganisms. Therefore they could be suitable for using as antimicrobial and antioxidative agents in the food industry.

Compositions and the in vitro antimicrobial activities of the essential oils of Achillea setacea and Achillea teretifolia (Compositae)

GC-MS analysis of the isolated essential oils from air-dried aerial parts of Achillea setacea and Achillea teretifolia, an endemic taxon, resulted in the identification of 51 constituents (79.8% of the total oil) and 42 constituents (87.1% of the total oil), respectively. Eucalyptol (1,8-cineole) was the major constituent of both oils studied (18.5 and 19.9%, respectively). The antimicrobial activities of the essential oils were individually evaluated against 14 microorganisms. Both oils exhibited inhibitory effects on Clostridium perfringens, Acinetobacter lwoffii and Candida albicans with a range of minimum inhibitory concentration values extended from 0.28 to 2.25 mg/ml. Camphor and their derivatives, borneol, terpinen-4-ol and eucalyptol (1,8-cineol) can be considered as the main antimicrobial constituents of the oils studied.

Composition and antimicrobial activity of Juniperus excelsa essential oil

The genus Juniperus (Cupressaceae) consists of 55 species, all of which occur throughout the northern hemisphere of the world [1]; eigth species of them grow in Turkey [2]. Evergreen shrubs and trees in this conifer genus are slow growing and long lived. Various species of juniper are used medicinally with a range of applications from antiseptic to diuretic [3, 4]. Juniperus excelsa M. Bieb. is a medium-sized shrub or tree up to 20 m. This species was divided into 2 subspecies (subsp. excelsa and subsp. polycarpos) by Farjon: one with a distribution in southeastern Europe, the Crimea, and mainly southern Turkey to Lebanon; the other a more continental element extending from North Turkey to Kirgizistan and Pakistan [5]. Subspecies excelsa is the subject of this paper. This subspecies is widespread in Turkey but most common in South Anatolia, in dry rocky slopes in hills and mountains at between 150‐2700 m, often forming the tree line in the Taurus mountains [5]. It is locally known as “boylu ardic” tall juniper in Turkey [6]. The chemical composition of the leaf and wood essential oils from Juniperus excelsa were previously reported [7‐9]. In the literature, there are a number of reports on the composition of the essential oil from berries of Juniperus species and their antimicrobial activities [10‐13]. Hexane and methanol extracts of J. excelsa were reported to demonstrate antimicrobial activity against microorganisms, including Mycobacterium tuberculosis [14]. The antimicrobial activity of J. excelsa essential oil against three standard bacterial strains and the yeast Saccharomyces cerevisiae have been reported [15]. The objective of this study was to determine the in vitro antimicrobial activity of the essential oil of the berries of J. excelsa and its main component, α-pinene, against clinically important microorganisms, including an anaerobic bacterium and the pathogenic yeasts. GS/MS analysis of J. excelsa essential oil resulted in the identification of forty-four constituents [16], representing 91.3% of the oil, as shown in Table 1. The major components were α-pinene (55.5%), α-cedrol (7.7%), sabinene (3.5%), and verbenone (2.4%). Similarly, Topcu et al. reported α-pinene (34.0%) and α-cedrol (12.3%) as the major components in the essential oil from berries of J. excelsa [17]. In another study, the main constituents were found to be α-pinene (29.1%) and carene (29.1%) [15]. The differences in the content of the oils might result from geographical origin, edaphic factors, or harvesting time. Antimicrobial chemotherapy has not achieved the much required success in the eradication of microbial infections because of the antimicrobial resistance developed by most pathogenic microorganisms. The antimicrobial properties of essential oils derived from many plants are under extensive study. The assays were performed as described elsewhere [18]. The results of this study shows that J. excelsa essential oil has a strong activity against the anaerobic bacterium Clostridium perfingens while exhibiting moderate activity against Staphylococus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Mycobacterium smegmatis , Candida albicans, and Candida krusei (Table 2). The data presented here are consistent with the previous studies which demostrated that α-pinene is a slightly active component [18]. The MICs of the main component of the essential oil, α-pinene, were also determined in parallel experiments, proving that this constituent is responsible for the antimicrobial activity, at least against C. perfringens and yeasts. Each plant extract and essential oil con tain complex mixtures of volatile and non-volatile compounds, and little is known about the effect of interactions between individual constituents on antimicrobial activity. Interactions between these components and known antibiotics may also lead to additive, synergistic, or antagonistic effects.

Chemical composition, antibacterial and antifungal activity of the essential oil of Thymbra spicata L. from Turkey.

The composition of the essential oil from aerial parts of Thymbra spicata L. from Turkey was analysed by GC-MS and its in vitro antimicrobial activity was examined. GC-MS analysis of the essential oil resulted in the identification of twenty-three constituents, representing 97.04% of the oil. The major compounds detected in the essential oil were carvacrol (60.39%), γ-terpinene (12.95%), and p-cymene (9.61%). The in vitro efficacy of the essential oil against 21 bacteria and seven Candida species was examined using disc diffusion and minimum inhibitory concentration (MIC) methods. The essential oil demonstrated strong anti-microbial activity in a wide spectrum against most microorganisms, particularly the yeasts tested. This is the first report on the anticandidal properties of the essential oil of T. spicata. In conclusion, this study confirms that T. spicata essential oil could be considered as a natural antimicrobial source.

Composition of the essential oil of Achillea schischkinii Sosn. (Asteraceae) from Turkey

Abstract The aerial parts of Achillea schischkinii were water distilled to produce oil, which was analyzed by GC, and GC/MS. Thirty-one components were identifed representing the 91.5% of the oil. The main components were 1,8-cineole (31.0%) and camphor (20.0%).