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  • Article
    Citation - WoS: 68
    Citation - Scopus: 91
    The Potential Medicinal Value of Plants From Asteraceae Family With Antioxidant Defense Enzymes as Biological Targets
    (Taylor & Francis Ltd, 2015) Koc, Suheda; Isgor, Belgin S.; Isgor, Yasemin G.; Moghaddam, Naznoosh Shomali; Yildirim, Ozlem
    Context: Plants and most of the plant-derived compounds have long been known for their potential pharmaceutical effects. They are well known to play an important role in the treatment of several diseases from diabetes to various types of cancers. Today most of the clinically effective pharmaceuticals are developed from plant-derived ancestors in the history of medicine. Objective: The aim of this study was to evaluate the free radical scavenging activity and total phenolic and flavonoid contents of methanol, ethanol, and acetone extracts from flowers and leaves of Onopordum acanthium L., Carduus acanthoides L., Cirsium arvense (L.) Scop., and Centaurea solstitialis L., all from the Asteraceae family, for investigating their potential medicinal values of biological targets that are participating in the antioxidant defense system such as catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPx). Materials and methods: In this study, free radical scavenging activity and total phenolic and flavonoid contents of the plant samples were assayed by DPPH, Folin-Ciocalteu, and aluminum chloride colorimetric methods. Also, the effects of extracts on CAT, GST, and GPx enzyme activities were investigated. Results and discussion: The highest phenolic and flavonoid contents were detected in the acetone extract of C. acanthoides flowers, with 90.305 mg GAE/L and 185.43 mg Q/L values, respectively. The highest DPPH radical scavenging was observed with the methanol leaf extracts of C. arvense with an IC50 value of 366 ng/mL. The maximum GPx and GST enzyme inhibition activities were observed with acetone extracts from the flower of C. solstitialis with IC50 values of 79 and 232 ng/mL, respectively.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 8
    Evaluation of Perylenediimide Derivatives for Potential Therapeutic Benefits on Cancer Chemotherapy
    (Wiley, 2012) Keskin, Taner; Isgor, Belgin S.; Isgor, Yasemin G.; Yukruk, Funda
    Perylene derivatives, known to have potential therapeutic benefits on particular cancer types as photosensitizers, may also function as small-molecule inhibitors with promising therapeutic value for diverse diseases. This recently recognized biological activity was attributed to their capacity to modulate the function of various enzymes as biological targets in vitro. Although the inhibitory activity on glutathione transferase and Src tyrosine kinase is important in determining the anticancer potential of compounds for target-specific drug design and development, to date, there are no successful inhibitors of this kind. Moreover, there are only a few studies about the effects of perylene derivatives on glutathione transferase and various kinases. In this study, four novel perylene compounds, N,N'-disubstituted perylenediimides and their 1,7-dibromo derivatives, were synthesized and evaluated for their biological activities. Here, among the compounds analyzed, one of them was identified with strong glutathione transferase inhibition and two with dual activity for both glutathione transferase and c-src inhibition. These results revealed that perylene derivatives may be employed as potential chemosensitizers to prevent chemotherapy-dependent drug resistance and identified as prospective anticancer agents with dual activity on both glutathione transferase and c-src enzymes.