A. Ahmet Başaran

Antioxidant activities of major thyme ingredients and lack of (oxidative) DNA damage in V79 Chinese hamster lung fibroblast cells at low levels of carvacrol and thymol

The leafy parts of thyme and its essential oil have been used in foods for the flavour, aroma and preservation and also in folk medicines. In the present study the genotoxicity of thymol and carvacrol was examined using comet assay. In V79 Chinese hamster lung fibroblast cells treated with 1, 5, 25 microM thymol and carvacrol, only 25 microM thymol caused some clastogenic DNA damage. For detection of oxidative DNA damage, the comet assay with formamido pyrimidine glycosylase (Fpg) protein was used: When V79 cells were treated with 1, 5, 25 microM thymol and carvacrol and post-treated with Fpg enzyme, no significant increase of Fpg-sensitive sites was observed at all concentrations studied. Reactive oxygen species (ROS) generation decreased slightly in the presence of thymol (1-100 microM) and carvacrol (5 microM) between 1 and 4h, yet increased at the highest 100 microM concentration of carvacrol after 24h. Thymol and carvacrol displayed a concentration dependent antioxidant capacity, whilst gamma-terpinene which lacks a phenolic group did not show any antioxidant capacity in the trolox equivalent antioxidant capacity (TEAC) assay. The results of this study indicate a lack of clastogenic activity for thymol and carvacrol at biologically relevant concentrations, and a moderate antioxidant activity in vitro.

An investigation of some Turkish herbal medicines in Salmonella typhimurium and in the COMET assay in human lymphocytes

Medicinal plants play a major role in the life of Turkish people and of late medicinal plant usage has increased in many countries. Green plants in general contain mutagenic and carcinogenic substances, but there is little information about the biological activities of herbal medicine. In the present study, therefore, various Turkish medicinal herbs were investigated for their genotoxic potential in the Salmonella typhimurium microsomal activation assay and the alkaline single cell gel electrophoresis (COMET) assay. Extracts from these medicinal herbs and some fractions of these extracts were examined. The species investigated were Arctium minus, Ecballium elatterium, Momordica charantia, Plantago major, Urtica dioica, Viscum album, Salvia triloba, Euphorbia rigida, Stachys lavandulifolia, Acteoside, Abies nordmannia. They are used for various immune disorders and are applied either topically or taken orally as a herbal tea. Of the 19 samples of the extracts and fractions investigated, none produced a positive response in strains TA98 and TA100 with or without metabolic activation, but all produced an increase above negative control values in the COMET assay. Some extracts were investigated further and produced dose-related increases. In the case of Urtica and Euphorbia species, where two fractions from these plants were examined, one fraction produced a greater response than the other. It is suggested that the lesser response of the fractions might be due to less DNA strand-breaking agents in the fractions or they may have antigenotoxic properties. The breaks that are detected in the COMET assay could be alkali-labile AP-sites and intermediates in base- or nucleotide-excision repair and are difficult to interpret in terms of hazard for man. Further studies with additional genotoxicity assays would be required to make such a prediction.

Protective effects of curcumin against oxidative stress parameters and DNA damage in the livers and kidneys of rats with biliary obstruction

Curcumin, a most active antioxidant compound, has been suggested to have potential beneficial effects against most metabolic and psychological disorders, including cholestasis. In the present study, the effects of curcumin against oxidative stress and DNA damage induced by bile duct ligation (BDL) in Wistar albino rats for 14 days were investigated. The rats were divided into three following groups: Sham group, the BDL group and the BDL+curcumin group. A daily dose of 50mg/kg curcumin was given to the BDL+curcumin group intragastrically for 14 days. The biomarkers of hepatocellular damage were decreased in the BDL+curcumin group compared to the BDL group, indicating that curcumin recovered the liver functions. DNA damage as assessed by the alkaline comet assay was also found to be low in the BDL+curcumin group. Curcumin significantly reduced malondialdehyde and nitric oxide levels, and enchanced reduced glutathione levels and catalase, superoxide dismutase, and glutathione S-transferase enzymes activities in the livers and kidneys of BDL group. Curcumin treatment in BDL group was found to decrease tumor necrosis factor-alpha levels in the livers of rats. These results suggest that curcumin might have protective effects on the cholestasis-induced injuries in the liver and kidney tissues of rats.

Phlinosides A, B and C, three phenylpropanoid glycosides from Phlomis linearis.

Three new phenylpropanoid glycosides, phlinosides A, B and C were isolated from a methanolic extract of the aerial parts of Phlomis linearis. On the basis of chemical and spectral evidence their structures were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-glucopyranosyl-(1----2)-a lpha-L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, 3,4 dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-alpha- L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha- L-rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, respectively.

The antioxidant and antigenotoxic properties of citrus phenolics limonene and naringin.

Phenolic compounds not only contribute to the sensory qualities of fruits and vegetables but also exhibit several health protective properties. Limonene and naringin are the most popular phenolics found in Citrus plants. In this study, we investigated the antioxidant capacities of limonene and naringin by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxic effects by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in Chinese hamster fibroblast (V79) cells. The genotoxic potentials of limonene and naringin were evaluated by micronucleus (MN) and alkaline COMET assays in human lymphocytes and V79 cells. Limonene and naringin, were found to have antioxidant activities at concentrations of 2-2000 µM and 5-2000 µM respectively. IC50 values of limonene and naringin were found to be 1265 µM and 9026 µM, respectively. Limonene at the concentrations below 10,000 µM and naringin at the all concentrations studied, have not exerted genotoxic effects in lymphocytes and in V79 cells. Limonene and naringin at all concentrations revealed a reduction in the frequency of MN and DNA damage induced by H2O2.

Antioxidant and antigenotoxic effects of lycopene in obstructive jaundice.

BACKGROUND Obstructive jaundice, a frequently observed condition caused by obstruction of the common bile duct or its flow and seen in many clinical situations, may end up with serious complications like sepsis, immune depression, coagulopathy, wound breakdown, gastrointestinal hemorrhage, and hepatic and renal failures. Intrahepatic accumulation of reactive oxygen species is thought to be an important cause for the possible mechanisms of the pathogenesis of cholestatic tissue injury from jaundice. Carotenoids have been well described that are able to scavenge reactive oxygen species. Lycopene, a carotenoid present in tomatoes, tomato products, and several fruits and vegetables, have been suggested to have antioxidant activity, so may play a role in certain diseases related to the oxidative stress. The aim of the present study was to determine the effects of lycopene on oxidative stress and DNA damage induced by experimental biliary obstruction in Wistar albino rats. MATERIALS AND METHODS Daily doses of 100 mg/kg lycopene were given to the bile duct-ligation (BDL) rats orally for 14 days. DNA damage was evaluated by an alkaline comet assay. The levels of aspartate transferase, amino alanine transferase, gamma glutamyl transferase, alkaline phosphatase, and direct bilirubin were analyzed in plasma for the determination of liver functions. The levels of malondialdehyde, reduced glutathione, nitric oxide, catalase, superoxide dismutase, and glutathione S transferase were determined in the liver and kidney tissues. Pro-inflammatory cytokine tumor necrosis factor-alpha level was determined in the liver tissues. Histologic examinations of the liver and kidney tissues were also performed. RESULTS According to this study, lycopene significantly recovered the parameters of liver functions in plasma, reduced malondialdehyde and nitric oxide levels, enhanced reduced glutathione levels, as well as enhancing all antioxidant enzyme activity in all tissues obtained from the BDL group. Moreover, the parameters of DNA damage in the liver and kidney tissue cells, whole blood cells, and lymphocytes were significantly lower in the lycopene-treated BDL group, compared with the BDL group. CONCLUSIONS Lycopene significantly reduced the DNA damage, and markedly recovered the liver and kidney tissue injuries seen in rats with obstructive jaundice.

Phlinosides D and E, phenylpropanoid glycosides, and iridoids from Phlomis linearis

Two new phenylpropanoid glycosides, phlinosides D and E were isolated from the methanolic extract of the aerial parts of Phlomis linearis, along with the known iridoid glucosides, lamiide, ipolamiide and auroside (= 5-hydroxy-8-epiloganin). On the basis of chemical and spectral evidence the structures of phlinosides D and E were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-al pha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside, respectively.

Two phenethyl alcohol glycosides from Scutellaria orientalis subsp. Pinnatifida

Two new phenethyl alcohol glycosides, darendoside A and B (= deacyl martynoside) were isolated from the methanolic extract of the aerial parts of Scutellaria orientalis subsp. pinnatifida, along with four known glycosides, syringin, martynoside, leucosceptoside A and verbascoside. On the basis of chemical and spectral evidence the structures of darendoside A and B were determined as beta-(4-hydroxyphenyl)ethyl O-beta-D-apiofuranosyl-(1-->2)-O-beta-D-glucopyranoside and beta-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-L-rhamnopyranosyl-(1-->3)-O-beta-D-glucopyranoside (= deacyl martynoside), respectively.

Modulating Effects of Pycnogenol® on Oxidative Stress and DNA Damage Induced by Sepsis in Rats

The aim of this study was to evaluate the protective effects of Pycnogenol® (Pyc), a complex plant extract from the bark of French maritime pine, on oxidative stress parameters (superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities and total glutathione (GSH) and malondialdehyde (MDA) levels), an inflammatory cytokine (tumor necrosis factor alpha (TNF‐α) level) and also DNA damage in Wistar albino rats. Rats were treated with 100 mg/kg intraperitonally Pyc following the induction of sepsis by cecal ligation and puncture. The decreases in MDA levels and increases in GSH levels, and SOD and GPx activities were observed in the livers and kidneys of Pyc‐treated septic rats. Plasma TNF‐α level was found to be decreased in the Pyc‐treated septic rats. In the lymphocytes, kidney, and liver tissue cells of the sepsis‐induced rats, Pyc treatment significantly decreased the DNA damage and oxidative base damage using standard alkaline assay and formamidopyrimidine DNA glycosylase‐modified comet assay, respectively. In conclusion, Pyc treatment might have a role in the prevention of sepsis‐induced oxidative damage not only by decreasing DNA damage but also increasing the antioxidant status and DNA repair capacity in rats. Copyright

Immunomodulatory activities of some Turkish medicinal plants.

The extracts of Arctium minus, Ecballium elaterium, Momordica charantia, Plantago major, Urtica dioica and Viscum album used for various disorders in Anatolia were investigated in vitro for their neutrophil chemotactic and intracellular killing activities by Boyden migration chamber and nitrozoblue tetrazolium (NBT) dye reduction tests, respectively. The extracts of Arctium minus, Momordica charantia, Urtica dioica and Viscum album were statistically active in chemotaxis and random migration tests. Also, the extracts of Urtica dioica seeds and leaves are suggested as possibly useful for patients suffering from neutrophil function deficiency. On the other hand, NBT results indicated that the extracts of Arctium minus, Ecballium elaterium and Viscum album have the ability to reduce active radicals suggesting that these extracts are also valuable in the medical treatment of some diseases associated with free radical damage.