Browsing by Author "Celep, Engin"

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    Effect of brewing material and various additives on polyphenolic composition and antioxidant bioactivity of commercial Tilia platyphyllos Scop. infusions
    (MARMARA UNIV, 2020-01-01) Bardakci, Hilal; Barak, Timur Hakan; Ozdemir, Kevser; Celep, Engin
    Herbal infusions have become very popular due to their pleasant flavor as well as their positive influence on health. The compositions of such infusions are affected by the extraction technique, duration, additives as well as container materials. This study implements comparison of antioxidant activities and phenolic contents of the infusions commercially purchased Tilia platyphyllos Scop. samples, one of the most preferred herbal infusions worldwide, prepared by using teapots with different materials. Antioxidant potencies of the samples were examined using tests with different mechanisms such as free radical scavenging test (DPPH), metal-related activity tests (CUPRAC, FRAP). On account of assessing the phenolic profile, total phenol, phenolic acid and flavonoid contents were estimated spectrophotometrically. In addition, the presence of protocatechuic acid in the extracts was investigated by HPTLC densitometry (between 0.762-1.037 w/w\%). Besides, antioxidant activities (DPPH, CUPRAC and TOAC) of the extracts were re-calculated after addition of natural/synthetic sweeteners, brown and white sugar, lemon, flower and pine honeys to the infusions. Results showed that the highest total antioxidant capacity was seen on Tiliae infusions prepared in ceramic teapot (672.80 +/- 1.40 mg AAE/g DE). Moreover, stevioside addition enhanced DPPH radical scavenging of Tiliae extracts (2781.76 +/- 44.38 EC50 in mu g/mL). This is the first report related with comparison of these brewing materials and additives in respect to their phenolic content and antioxidant activity of herbal teas.
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    In Vitro Anti-Aging Potential Evaluation of Maclura pomifera (Rafin.) Schneider 80\% Methanol Extract with Quantitative HPTLC Analysis
    (GALENOS PUBL HOUSE, 2022-01-01) Barak, Timur Hakan; Celep, Inci Kurt; Senturk, Tugba Buse; Bardakci, Hilal; Celep, Engin
    Objectives: Maclura pomifera (Rafin.) Schneider is a widespread species all around the world, which is also frequently cultured for ornamental purposes. Previous studies revealed that M. pomifera fruits are rich in prenylated isoflavonoids, exhibit noteworthy biological activities, and have probable benefits, particularly, when applied topically. Considering that phenolic compounds are important sources in the development of anti -aging cosmetic products, this study investigated the anti-aging potential of M. pomifera 80\% methanolic extract (MPM) by evaluating antioxidant and extracellular matrix degrading enzymes inhibiting activity. Materials and Methods: For this study, the inhibitory potential of 80\% MPM against different enzymes associated with the aging process was evaluated. Given the unequivocal role of oxidative stress in aging, in vitro antioxidant tests were employed as well. Moreover, osajin was determined as the major bioactive isoflavonoid of the sample by high performance thin layer chromatography analysis. Results: Results of the mechanistically different antioxidant assays exhibited notable antioxidant potential of the extract. Inhibition potential of MPM against hyaluronidase, collagenase, and elastase enzymes, which are directly linked to acceleration of the aging process, was investigated and results revealed that MPM inhibited the aforementioned enzymes explicitly. MPM had notable phenolic and flavonoid content