Ufuk Özgen

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 and antimicrobial activities of Onosma argentatum and Rubia peregrina

The n-hexane-dichloromethane (1:1) extract of the roots of Onosma argentatum and the methanol extract (partitioned between water and chloroform, ethyl acetate and n-butanol, respectively), of the underground parts (roots and rhizomes) of Rubia peregrina were tested in vitro for their antioxidant and antimicrobial activities. The highest antioxidant activity (98%) was observed at 0.1% concentration for the roots of O. argentatum. It was 96% at 0.25% concentration on the ethyl acetate fraction of R. peregrina. O. argentatum extract was effective on Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The ethyl acetate and chloroform fractions of R. peregrina were effective on S. aureus and E. coli, respectively. These two species did not have any antifungal activity.

An investigation on the anticandidal activity of some traditional medicinal plants in Turkey.

Methanol and chloroform extracts obtained from eight plant species belonging to six families, which were selected depending on their use in Turkish folk medicine, including Mentha longifolia L. (Labiatae), Mentha piperita L. Hudson (Labiatae), Prongos ferulaceae (Umbelliferae), Galium verum L. (Rubiaceae), Salvia limbata C. A Meyer (Labiatae), Artemisia austriaca Jacq. (Artemiceae), Plantago lanceolata L. (Plantaginaceae) and Urtica dioica L. (Urticaceae) were evaluated for their in vitro anticandidal activity. The anticandidal activity of extracts against 99 human pathogenic clinical isolates belonging to 35 Candida albicans, 33 Candida tropicalis and 31 Candida glabrata and standard strains of Candida spp. (C. albicans ATCC 10231, C. glabrata ATCC 80030 and C. tropicalis ATCC 22019) were tested by disc diffusion method and the active extracts were assayed for the minimal inhibitory concentration (MIC). Chloroform extracts of plants have no inhibitory effect against both clinical and standard strains of Candida spp., whereas methanol extracts exhibited good activity. Among the plants tested, M. piperita showed the highest anticandidal activity with 12.3 mm inhibition zone and 1.25 mg ml−1 MIC value against C. albicans, M. longifolia, P. lanceolata and A. austriaca also displayed activity against C. albicans and C. tropicalis.

A New Sulfated α-Ionone Glycoside from Sonchus erzincanicus Matthews

Sonchus erzincanicus (Asteraceae) is an endemic species in Turkey, where six Sonchus species grow. In this study, a phytochemical study was performed on the aerial parts of the plant. The study describes the isolation and structure elucidation of five flavonoids and two α-ionone glycosides from S. erzincanicus. The compounds were isolated using several and repeated chromatographic techniques from ethyl acetate and aqueous phases that were partitioned from a methanol extract obtained from the plant. 5,7,3′,4′-Tetrahydroxy-3-methoxyflavone (1) and quercetin 3-O-β-D-glucoside (2) were isolated from the ethyl acetate phase, while corchoionoside C 6’-O-sulfate (3), corchoionoside C (4), luteolin 7-O-glucuronide (5) and luteolin 7-O-β-D-glucoside (6), apigenin 7-O-glucuronide (7) were isolated from the aqueous phase. Corchoionoside C 6’-O-sulfate (3), isolated for the first time from a natural source, was a new compound. The structures of the compounds were elucidated by means of 1H-NMR, 13C-NMR, 2D-NMR (COSY, HMQC, HMBC) and ESI-MS.