Maksut Coşkun

Hydroxybenzoic acids from Boreava orientalis

A new guaiacylglycerol ether, threo-guaiacylglycerol-8′-vanillic acid ether, pyrocatechuic acid, pyrocatechuic acid 3-O-β-d-glucoside, gentisic acid, gentisic acid 5-O-β-d-glucoside, vanillic acid and vanillic acid 4-O-β-d-glucoside were identified from fruits of Boreava orientalis. Structural elucidation was carried out on the basis of UV, mass, 1H and 13C NMR spectral data, including 2D shift-correlation and selective INEPT experiments.

Antioxidant Properties of Some Medicinal Lamiaceae (Labiatae) Species

Abstract In this study, antioxidant properties of Thymus sipyleus. Boiss. subsp. sipyleus. var. sipyleus., Teucrium chamaedrys L.., Mentha longifolia. (L.) Hudson subsp. longifolia., Salvia limbata. C.A. Meyer, and Thymus fallax. Fisch. & Mey. were investigated. Antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, reducing powers, and the amount of total phenolic compounds of the extracts were studied. The highest antioxidant activity was shown by T. chamaedrys. (decoction, IC50: 9.2 µg/ml), and the lowest one was S. limbata. (decoction, IC50: 619.5 µg/ml). The highest DPPH radical scavenging activity was shown by T. fallax. [decoction, IC50S: 56 µg/ml (IC50S is the extract concentration (µg/ml) required for 50% inhibition of the DPPH solution absorbance at 517 nm)] while the lowest one was S. limbata. (decoction, IC50S: 335.8 µg/ml). The highest reducing power and amount of total phenolic compounds was shown by T. chamaedrys. (decoction, 29.9 µg/ml ascorbic acid equivalent, 27.9 µg/ml gallic acid equivalent, respectively), and the lowest one was S. limbata. (decoction, 5.1 µg/ml ascorbic acid equivalent, 9.9 µg/ml gallic acid equivalent, respectively) at 250 µg/ml extract concentration.

Antioxidant Activity Studies on Selected Sideritis Species Native to Turkey

ABSTRACT Sideritis. L. species are widely used as medicinal plants and as herbal teas in Turkey, in which 45 species of the genus are naturally found. The aim of this study was to determine the antioxidant activity of Sideritis. species found in the Mediterranean region. In this study, the antioxidant activities of the lyophilized extracts obtained from aerial parts of 17 species (18 taxa) of Sideritis. were compared, of which 15 taxa were endemic. The antioxidant activities of aqueous extracts were studied by two different techniques: qualitative DPPH (1,1-diphenyl-2-picrylhydrazyl radical) assay to detect the free radical scavenging activity and the TBA assay to detect liposome lipid peroxidation. All the extracts (except S. erithrantha. subsp. erithrantha., S. dichotoma., S. syriaca. subsp. nusariensis., S. tmolea.) showed a strong antioxidant activity with the DPPH test. High activity was observed in the S. brevibracteata. (IC50 mg/ml = 0.16), S. condensata. (IC50 mg/ml = 0.33), S. serratifolia. (IC50 mg/ml = 0.31) extracts with the lipid peroxidation assay method.

Flavonoids from Rhamnus pallasii

Abstract A new dihydroflavonol, pallasiin, together with kaempferol, quercetin, isorhamnetin, mearnsetin, aromadendrin, eriodictyol and taxifolin, has been isolated from the bark of Rhamnus pallasii and its structure elucidated as 2,3-dihydromyricetin 4′- O -methyl ether.

Sinapinyl but-3-enylglucosinolate from Boreava orientalis

A new glucosinolate salt, named boreavan A, has been isolated from fruits of Boreava orientalis. Its structure has been established as sinapinyl but-3-enylglucosinolate on the basis of chemical and spectral evidence, including 2D-shift correlation and DEPT NMR experiments.

An anthraquinone glycoside from Rhamnus pallasii

Abstract A new anthraquinone glycoside, together with α-sorinin, has been isolated from the bark of Rhamnus pallasii and its structure elucidated as physc

Antimicrobiological Studies on Turkish Cistus. Species

ABSTRACT The genus Cistus. L., mainly growing in the Mediterranean region, is represented by five species in Turkey: C. creticus. L., C. laurifolius. L., C. monspeliensis. L., C. parviflorus. Lam., and C. salviifolius. L. In this study, in vitro. antimicrobial activity of water, methanol, chloroform, ethyl acetate, and buthanol extracts, prepared from dried and powdered leaves and the fruits of the five Cistus. species, were investigated by the disk diffusion method against the following microorganisms: Staphylococcus aureus. (ATCC 29213 and ATCC 25923), Streptococcus faecalis. (ATCC 29212), Bacillus subtilis. (ATCC 6633), Bacillus cereus. (RSKK 1122), Pseudomonas aeruginosa. (ATCC 27853), Escherichia coli. (ATCC 25922), and Candida albicans. (ATCC 10231). Chloroform, ethyl acetate, butanol, and the remaining aqueous extracts, obtained from the fractionation of methanol extract, were also tested. All of the extracts showed some activity against B. subtilis. and B. cereus.. Lyophylized extracts showed the highest activity against Staphylococcus aureus. 25923 and 29213. Buthanol extracts of the leaves and fruits of C. creticus. showed the highest activity. Extracts of all Cistus. species did not show any activity against Pseudomonas aeruginosa. and Candida albicans..

Dihydrobenzofuran lignans from Boreava orientalis

Abstract Two new dihydrobenzofuran lignanamides and three known dihydrobenzofuran lignans have been isolated from fruits of Boreava orientalis. The structures of the two new compounds were established as cis- and trans- (2 R ,3 S )-2,3-dihydro-2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-7-methoxybenzofuran-5-propen-1-ic(1,5-dimethyl)glutamate amide on the bases of chemical and spectral evidence, including NOE, 2D shift-correlation and HMBC NMR experiments.

HPLC Analysis of the Anthraquinones from Rhamnus Species Growing in Turkey

AbstractThe main anthraquinones from the bark of four Rhamnus species were separated with RP-HPLC. The external standard method was used for quantitative determination of anthraquinones.

Chromatographic Separation and Identification of Sildenafil and Yohimbine Analogues Illegally Added in Herbal Supplements

Herbal medicines are major source of aphrodisiacs and have been used worldwide for thousands of years by different cultures and civilizations. Recently, consumption of dietary supplements has been becoming more popular around the world. Unfortunately, the adulteration of dietary supplements with undeclared synthetic chemical compounds is steadily increasing according to the literature. Some herbal products advertised as “all natural” have in contrast been found to contain synthetic PDE-5 inhibitors. There are currently three PDE5 inhibitors Sildenafil (Langtry & Markham, 1999) (Viagra; Pfizer, New York, US), Tadalafil (Meuleman, 2003) (Cialis; Eli Lilly, Indianapolis, US), and Vardenafil (Keating & Scott, 2003) (Levitra; Bayer Pharmaceuticals Co, Wuppertal, Germany), approved worldwide for the treatment of male erectile dysfunction, further two agents Udenafil (Salem et al., 2006) (Zydena; Dong-A PharmTech Co, Korean), Mirodenafil (Jung, 2008) (Mvix, Life Science R&D Center of SK chemical, Beijing, Tianjin, Shanghai) were licensed only in Korea. They produce vascular smooth muscle relaxation, promote penile blood flow, and hence, induce erection. These kinds of commercially available herbal aphrodisiac products have been spiked with the above-mentioned legal drugs, but also with their analogues, which have not been subjected to formal pharmacokinetic or other pharmacological testing in either humans or animals.