Browsing by Author "Ersoy, Seyda Karaman"

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Citation Count: 0
Combined Spectroscopic and Chromatographic Techniques Augmented With Chemometrics for the Authentication of Black Cumin ( Nigella Sativa L . ) Seed Oil
(Academic Press inc Elsevier Science, 2024) Karaman Ersoy, Şeyda; Ersoy, Seyda Karaman; Kaya, Elif Nilay; Senol, Onur; Apak, Resat; Temel Eczacılık Bilimleri Bölümü
Edible oils adulteration has a great concern because of its health and economical effects. Black cumin seed oils (BCSOs) are one of the most adulterated edible oils. In this case, the purpose of this research was to investigate authenticity of commercial BCSOs by spectroscopic and chromatographic techniques combined with orthogonal partial least square -discriminant analysis (OPLS-DA) and hierarchical cluster analysis (HCA). Sixteen commercial BCSO samples (100 % pure-certified and other BCSOs), potential blending oils (sunflower, corn, and soybean oils), and twenty-one synthetically adulterated BCSO samples blended with sunflower (SFO), corn (CO), and soybean (SBO) oils at levels of 5 %, 10 %, 15 %, 20 %, 30 %, 40 %, and 50 % (v/v) were analysed. Screening of potential fingerprinting markers such as thymohydroquinone (THQ), thymoquinone (TQ), carvacrol (CRV), tocopherol isomers ( alpha-, gamma -, and delta -), as well as total antioxidant capacity and phenolic content analysis were carried out utilizing spectrophotometric CUPRAC, ABTS, and Folin Ciocalteu ' s assays. Commercial pure and fraudulent BCSOs and synthetically adulterated samples were successfully classified in OPLS-DA graphs with 95 % confidence level. Even to five percent detection limit for SFO, CO and SBO adulteration were prominently monitored. In consequence, the proposed spectroscopic and chromatographic methods seem to be a practically applicable, sensitive and versatile protocol that can be used as an alternative fingerprinting procedure to determine adulteration of commercial BCSOs.
Citation Count: 0
Comparison of Total Antioxidant Capacities and Phenolic Constituents of Grapes Cultivated in Turkey for Wine Production
(Taylor & Francis inc, 2024) Karaman Ersoy, Şeyda; Vural, Turkan; Baskan, Kevser Sozgen; Tutem, Esma; Temel Eczacılık Bilimleri Bölümü
Grapes are renowned for their health-promoting properties due to polyphenols, particularly anthocyanins in red grapes and flavonols in white grapes. This study evaluated the total antioxidant capacities (TAC) of specific grape varieties (Sultaniye, Chardonnay, Shiraz, Carignan, Alicante Bouschet, and Merlot) using the CUPRAC (CUPric Reducing Antioxidant Capacity) and ABTS/HRP (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/horseradish peroxidase) methods. Additionally, total phenolic, flavonoid, and anthocyanin contents were determined via Folin Ciocalteu, AlCl3/NaNO2, and pH differential methods. Primary phenolic compounds were identified with High-Performance Liquid Chromatography-Photodiode Array (HPLC-PDA). TAC values of the grape juices (mmol Trolox L-1) ranked as Alicante > Shiraz > Sultaniye > Carignan > Merlot > Chardonnay by CUPRAC, and Shiraz > Alicante > Merlot > Carignan >= Sultaniye > Chardonnay by ABTS/HRP and for skin extracts (mmol Trolox g(-1)), Carignan > Alicante > Shiraz > Merlot > Chardonnay > Sultaniye by CUPRAC, and Carignan > Shiraz > Alicante > Merlot > Chardonnay > Sultaniye by ABTS/HRP. The study demonstrated a strong correlation between phenolic composition and TAC values in grape samples, with anthocyanins as the predominant family contributing significantly to TAC. Varietal and intra-fruit differences in specific phenolic compounds were found to account for variations in observed TAC levels. Specifically, grape skin samples showed a more robust correlation between antioxidant capacity and total phenolic content (r = 0.986) than grape juices (r = 0.777). These findings underscore the considerable variation in antioxidant potential among grape varieties and emphasize the critical role of phenolic composition in the health-related benefits of grape consumption.
Citation Count: 0
Isolation of Rosmarinic Acid From Rosemary Extract Utilizing a Molecularly Imprinted Polymer
(Springer, 2025) Ersoy, Seyda Karaman
Molecularly imprinted polymers are polymeric materials engineered with specific templates capable of recognizing molecules selectively. Rosmarinic acid, an ester formed from caffeic acid and 3,4-dihydroxyphenyllactic acid and commonly occurring in plants, exhibits a broad spectrum of bioactive properties, including antioxidant, antiviral, analgesic, antibacterial, antimutagenic, antiallergic, anti-inflammatory, and neuroprotective effects. It is prominently present in rosemary (Rosmarinus officinalis) extracts, where it acts as the primary phenolic compound responsible for antioxidant activity. Advancements in the refining techniques for recovering and purifying rosmarinic acid from rosemary extracts have driven progress in molecularly imprinted solid-phase extraction methods. Remarkably, the molecularly imprinted solid-phase extraction approach utilizing the 1:4:16 caffeic acid-imprinted polymer exhibited outstanding selectivity for rosmarinic acid in authentic rosemary samples, achieving a purity level of 84% +/- 2.96%. This research marks a significant advancement in the literature, being the first to demonstrate the effective purification of rosmarinic acid using caffeic acid-imprinted polymers. These findings underscore the efficacy of the MIPs in accurately capturing rosmarinic acid, illuminating their potential applications in pharmaceutical and analytical settings where precise molecule recognition and extraction methodologies are crucial. This innovative approach not only enhances the extraction process but also opens new avenues for the application of MIPs in various fields, including food chemistry and natural product research.