Ersin Yücel

Antimicrobial Activities of Fruits of Crataegus and Pyrus Species

Abstract The antimicrobial activity of the ethyl acetate extracts from fruits of Crataegus tanacetifolia., Crataegus x bornmülleri., Pyrus communis. subsp. communis., and Pyrus serikensis. (Rosaceae) were investigated by the agar-well diffusion assay, and the extracts exhibited antimicrobial effect against most of the bacteria and all of the yeasts tested. Although the plants differed in their activities against the microorganisms tested, the extracts of C. x bornmülleri. and P. communis. subsp. communis. displayed no antifungal activity against the fungi tested. P. serikensis. extract inhibited the growth of all bacteria tested but not Aspergillus niger., Aspergillus parasiticus., Aspergillus citri., and Aspergillus fumigatus.. In conclusion, P. serikensis. was the most active antimicrobial plant. Particularly, P. serikensis. extract showed significant antifungal activities and could be used as an antimicrobial agent in new drug therapy.

Composition of the Essential Oil of Three Endemic Centaurea Species From Turkey

Abstract The essential oil obtained by hydrodistillation from three endemic Centaurea species (Asteraceae) in Phalolepis (Cass.) DC. Section; C. wagenitzii Hub.-Mor., C. tossiensis Freyn et Sint. and C. luschaniana Heimerl from Turkey were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS), simultaneously. Main constituents of the oils were found as hexadecanoic acid (25.6 %, 50.6 % and 40.0 %, respectively). Fatty acids and their esters were identified as the main constituent groups of the three species.

Pollen morphology of some endemic Turkish Centaurea L. (Asteraceae, section Phaloletis ) and their taxonomic value

In this study, the detailed pollen morphological structures of some endemic Turkish species of Centaurea amaena Boiss., C. antalyense H. Duman & A. Duran, C. aphrodisea Boiss., C. hierapolitana Boiss., C. luschaniana Heimerl, C. lycia Boiss., C. tossiensis Freyn. Et Sint., and C. wagenitzii Hub.-Mor. (Asteraceae, section Phaloletis) were studied under light microscopy (LM) and scanning electron microscopy (SEM) for the first time. LM and SEM investigations showed that the pollen grains of eight taxa are more or less spheroidal-subprolate, the amb triangular and tricolporate. The exine sculpture is tectate, microechinate-scabrate in the pollen of Centaurea taxa. Spinules are less dense in Centaurea amaena, C. antalyense, C. hierapolitana, and C. lycia, but they are more dense in C. aphrodisea, C. luschaniana, C. tossiensis, and C. wagenitzii. Spinule dimensions are different from each other. The exine has one layer of columellae beneath the spines. We determined all taxa that have the Helianthoid type. Exine sctructure and sculpture as well as spine density and dimensions in Asteraceae are the most reliable characteristics for discriminating taxa.