Effect of Laurus nobilis L. Essential Oil and its Main Components on α-glucosidase and Reactive Oxygen Species Scavenging Activity.

The present study was designed to determine the effects of the essential oil of Laurus nobilis L. (Lauraceae) and its three main components on α-glucosidase and reactive oxygen species scavenging activity. The chemical composition of the essential oil from Laurus nobilis L. leaves was analyzed by GC/GC-MS and resulted in the identification of 29 compounds, representing 99.18% of the total oil. 1,8-cineole (68.82%), 1-(S)-α-pinene (6.94%), and R-(+)- limonene (3.04%) were determined to be the main components. The antioxidant features of the essential oil and its three main components were evaluated using inhibition of 2,2-diphenyl-1- picrylhydrazyl, hydroxyl, and superoxide radicals, inhibition of hydrogen peroxide and lipid peroxidation assays. The results show that the DPPH, hydroxyl, and superoxide radical as well as hydrogen peroxide scavenging activities of the essential oil are greater than the positive controls and the three main components of the oil when tested independently. The inhibition of lipid peroxidation by the oil occurred less frequently than with 1,8-cineole and R-(+)- limonene alone, but the effects were more pronounced than those seen with 1-(S)-α-pinene and the positive controls. An α-glucosidase inhibition assay was applied to evaluate the in-vitro antidiabetic activity of the essential oil. IC50-values were obtained for laurel essential oil, 1, 8-cineole, 1-(S)-α-pinene, and R-(+)-limonene: 1.748 µL/mL, 1.118 µL/mL, 1.420 µL/mL and 1.300 µL/mL, respectively. We also found that laurel essential oil and 1, 8-cineole inhibited the α-glucosidase competitively while 1-(S)-α-pinene and R-(+)-limonene were uncompetitive inhibitors.

Investigation of oxidative stress during fracture healing in the rats.

One of the most damaging effects of reactive oxygen species (ROS) is lipid peroxidation, the end-product of which is malondialdehyde (MDA). This study was aimed to evaluate erythrocyte MDA levels during fracture healing in rats. Thirty male rats were used and the rats were divided into two groups to serve as controls and tests. Six rats were used as a control group that was not subject to fracture. The remaining 24 rats were divided into four groups and erythrocyte MDA levels were examined on days 5, 10, 20 and 30 post fracture. The right fibulas of rats were broken by manual angulation in the experimental group. The erythrocyte malondialdehyde level was measured in the experimental and control groups. The difference between malondialdehyde levels of control and experimental groups was statistically significant (p<0.05). Oxidative stress clearly increases during fracture healing in rats.

The in vitro antioxidant and antimicrobial activities of the essential oil and methanol extracts of Achillea biebersteini Afan. (Asteraceae).

The essential oil and methanol extracts from A. biebersteinii Afan. (Asteraceae) were evaluated for their antimicrobial and antioxidant activities in vitro. The oil showed stronger antimicrobial activity than the extracts. Their antioxidant features were also evaluated using diphenyl-1-picrylhydrazyl (DPPH), inhibition of superoxide and hydroxyl radicals and inhibition of the lipid peroxidation assays. Particularly, polar subfraction of the methanol extract showed antioxidant activity. The GC-MS analysis of the oil has resulted in the identification of 23 components; piperitone, eucalyptol, camphor, chrysanthenone and borneol were the main components. Antimicrobial activity tests carried out with the fractions of the oil showed that the activity was mainly observed in those containing eucalyptol and camphor, in particular, followed by borneol and piperitone.

Effects of Rhus coriaria L (Anacardiaceae) on lipid peroxidation and free radical scavenging activity.

In order to evaluate the antioxidant potential of Rhus coriaria L. (Anacardiaceae), a well-known spice, the methanolic extract (water-soluble part) was prepared and investigated using free radical-generating systems in vitro. The IC(50) value of the extract for lipid peroxidation was estimated as 1200 microg/mL in the Fe(+2)-ascorbate system while those for superoxide-scavenging activity in the xanthine-xanthine oxidase method and hydroxyl radical scavenging activity in the deoxyribose decomposition method were 282.92 microg/mL and 3850 microg/mL, respectively. These data suggest that the methanolic extracts of Rhus coriaria L. fruits have considerable antioxidant activity against free radicals and lipid peroxidation in vitro, a fact that may encourage in vivo studies.

Chemical and antioxidant properties of Laurocerasus officinalis Roem. (cherry laurel) fruit grown in the Black Sea region.

Laurocerasus officinalis Roem. is a summer fruit highly characteristic of the Black Sea region. The edible parts of the fruit were tested for chemical composition and antioxidant properties. Total moisture, ash, protein, sugar, pectin, ascorbic acid, phenolic, and mineral contents of the fruit were determined. The antioxidant activity of the fruit was investigated using TLC plate and ferric thiocyanate methods. Its antioxidative character was also tested utilizing hydroxyl, DPPH, and superoxide radical scavenging activity measurements, using BHT, vitamin C, and Trolox as references. Besides being a good source of nutrients, L. officinalis was found to provide a rich source of protective antioxidant compounds. Its antioxidant and radical scavenging activities were comparable to or higher than those of the reference antioxidants. It appeared to have high mineral content. The concentrations of macroelements K, Mg, Ca, and Na were high at 2215 +/- 10.5, 179 +/- 11, 153 +/- 0.8, and 55 +/- 0.3 mg/kg, respectively, and the concentrations of trace elements Mn, Fe, Zn, and Cu were 24.2 +/- 1.3, 8.3 +/- 0.8, 1.9 +/- 0.2, and 0.8 +/- 0.1 mg/kg, respectively. In addition, the fruit showed very low contents of Pb, Ni, Co, and Cr, below the detection limits, which is considered to be a good food quality. As it is a rich source of protein, sugar, ascorbic acid, minerals, and antioxidants, L. officinalis is well worth further studies regarding its components possessing important health benefits and inclusion in the daily diet.

Antioxidant and antimicrobial activity of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae).

The in vitro antimicrobial and antioxidant activities of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae) were investigated. GC-MS analysis of the essential oil resulted in the identification of 36 compounds constituting 90.8% of the total oil. Eucalyptol, camphor, alpha-terpineol, beta-pinene, and borneol were the principal components comprising 60.7% of the oil. The oil strongly reduced the diphenylpicrylhydrazyl radical (IC(50)=1.56 micro g/ml) and exhibited hydroxyl radical scavenging effect in the Fe(3+)-EDTA-H(2)O(2) deoxyribose system (IC(50)=2.7 micro g/ml). It also inhibited the nonenzymatic lipid peroxidation of rat liver homogenate (IC(50)=13.5 micro g/ml). The polar phase of the extract showed antioxidant activity. The oil showed antimicrobial activity against Streptococcus pneumoniae, Clostridium perfringens, Candida albicans, Mycobacterium smegmatis, Acinetobacter lwoffii and Candida krusei while water-insoluble parts of the methanolic extracts exhibited slight or no activity. This study confirms that the essential oil of Achillea millefolium possesses antioxidant and antimicrobial properties in vitro.

Effect of Rhus coriaria L. (Anacardiaceae) on superoxide radical scavenging and xanthine oxidase activity.

Rhus coriaria L. (Anacardiaceae) is a well-known spice in the Middle-East and grown in the Central and East Anatolia region of Turkey. A methanolic extract (water-soluble part constituents) of R. coriaria, was found to be an uncompetitive inhibitor of xanthine oxidase and scavenger of superoxide radical in vitro with IC50 values of 172.5 microg/mL and 232 microg/mL respectively. Superoxide radicals were generated either by an enzymatic or a non-enzymatic system, and scavenging ability was evaluated by the inhibition of nitroblue tetrazolium reduction. This study provides evidence that a crude extract of R. coriaria exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to uncompetitively inhibit xanthine oxidase.

Antimicrobial and antioxidant activity of the essential oil and methanol extracts of Thymus pectinatus Fisch. et Mey. Var. pectinatus (Lamiaceae).

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.

Effect of vitamin C and zinc on osmotic fragility and lipid peroxidation in zinc-deficient haemodialysis patients.

Peroxidation of the membrane lipid structure of red blood cell leads to haemolysis and anaemia in haemodialysis patients. Dietary constituents of antioxidant vitamins and trace elements may play an important role in protecting against oxidant damage. In this study, the effects of supplementation of vitamin C and zinc on osmotic fragility and lipid peroxidation of erythrocytes were investigated in 34 zinc-deficient haemodialysis patients. Sixteen sex- and age-matched normal volunteers acted as controls. Patients were randomized to receive vitamin C (250 mg day(-1)), zinc (20 mg day(-1)) or a placebo treatment for 3 months. The levels of vitamin C, zinc, malondialdehyde (MDA) and osmotic fragility were measured initially and 3 months after supplementation. Mean serum concentration of vitamin C and zinc increased significantly in the groups at the end of the respective study periods. Supplementation with vitamin C and zinc improved osmotic fragility, and decreased the level of MDA in the groups, but some side-effects (i.e. nausea, vomiting, fever, muscle pain, weakness) were observed during the zinc treatment. The results showed that the supplementation of both treatments decreased osmotic fragilty and MDA in zinc-deficient haemodialysis patients. However, vitamin C treatment was found to be safer than zinc supplementation.

Normal thyroid volume by ultrasonography in healthy children.

With the objective of creating standards for the volume of the thyroid gland by ultrasonography in the 0-16-year age group, thyroid volumes of 302 healthy children (150 boys, 152 girls) were measured by ultrasonography. The transverse (x), sagittal (y) and anteroposterior (z) lengths of the right and left lobes and isthmus were measured. Volumes of these were calculated by the ellipsoid volume formula [V = (pi/6) x x x y x z]. Statistical analysis was done using the Kruskal-Wallis and Student t tests. The cases were divided into six and eight groups by age and height, respectively. There was a significant positive correlation between thyroid volume, age, height and weight. Thyroid volumes in children of 12 years and over were significantly different from those in the younger age groups.