Some phenolic compounds, antioxidant capacity and essential oil composition of hypericum thymopsis boiss (Hypericaceae)

Aim: The aim of this thesis is determination of morphological properties, essential oil composition, antioxidant capacity and some phenolic compounds of the Hypericum thymopsis which is endemic in Turkey. Material and Method: Plant materials were collected during the field studies. Morphological studies are made by character analysis and measurements on samples. DPPH and ABTS methods were used to determine the antioxidant activities. Phenolic compounds are determined by HPLC analysis method. Essential oil analysis is performed by GC/MS analysis method on the samples of three different populations. Results: The specimens belonging to some population shows differences such as; longer stem length (15-20 cm), more translucent glands number in the leaf (c.50), larger sepals (2-2.5 x 1 mm) and the more sepal gland number (8 gland) in morphological examination. The highest antioxidant effect is showed by floral extracts in the DPPH method, according to IC50 values in the examined samples. The most powerful radical scavenging capacity in the ABTS method is showed by leaf extract of sample TA3004 (87.42 μg/ml). The major components are determined as α-Pinene, Spathulenol and Limonene. In leaf extract 7.040 mg/kg routine, 4.463 mg/kg quersetin, in floral extract 1.992 mg/kg hyperisin, 11.213 mg/kg routine and 4.250 mg/kg quercetin is determined. Conclusion: Morphological differences are evaluated within the extended circumscribe of the description of the species. The antioxidant properties of Hypericum thymopsis is given first time in this study. Different chemotypes of species are determined with essential oil analysis. In addition, some phenolic contents of the samples are determined.