Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
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Article Lipoxygenase Inhibitory Activity Evaluation of Achillea Biebersteinii Afan. by Activity-Guided Fractionation(Elsevier Ireland Ltd, 2026) Subasi, Bilgen; Gunbatan, Tugba; Gurbuz, Ihan; Dilmac, Elif; Bedir, Erdal; Demirci, FatihEthnopharmacological relevance: Achillea biebersteinii Afan. is traditionally utilized as folk medicine for a broad range of therapeutic applications, especially for promoting the maturation of abscesses, wound healing; against inflammation, and rheumatism in T & uuml;rkiye. Aim of the study: The anti-inflammatory potential of A. biebersteinii was evaluated through activity-guided fractionation (AGF) targeting lipoxygenase (15-LOX) inhibition. Materials and methods: Different chromatographic techniques were used for the AGF of the ethyl acetate extract of A. biebersteinii aerial parts. The in vitro 15-LOX inhibitory activity evaluation was performed to address the antiinflammatory activity. The structures of purified compounds from the fractions were confirmed by LC-HRMS, 1H NMR, and 13C NMR analyses, respectively. Results: The fractionation and isolation process culminated in the identification of three key flavonoids namely; patulitrin, axillarin, quercetagetin-7-O-beta-glucopyranoside, and 4,5-dicaffeoylquinic acid, which showed statistically remarkable 15-LOX inhibitory activity with inhibition rates of 82.27%, 96.81 %, 84.65% and 77.47 %, respectively. Two flavonoids were isolated by using the AGF method, where quinic acid was spotted to have significant 15-LOX inhibitory activity. Conclusion: These findings support the future therapeutic potential of A. biebersteinii as a natural antiinflammatory source.Article Citation - WoS: 12Citation - Scopus: 12Isolation of Rosmarinic Acid and Methyl Rosmarinate as Lipoxygenase Inhibitors From Salvia Palaestina Benth. by Activity-Guided Fractionation(Elsevier, 2021) İçen, Mehmet Sina; Gürbüz, İlhan; Bedir, Erdal; Günbatan, Tuğba; Demirci, FatihSalvia palaestina aqueous and methanol extracts were prepared from the aerial parts, which were evaluated for the in vitro anti-inflammatory properties using the lipoxygenase (LO) enzyme inhibition assay. While the aqueous extract showed no activity at test concentrations, a significant (p < 0.001) lipoxygenase inhibition was detected for the methanol extract with 29% inhibition. Activity guided fractionation was carried out on the methanol extract via liquid-liquid partitioning using n-hexane, dichloromethane, ethyl acetate, and n-butanol. The ethyl acetate fraction showed statistically the best inhibition among the sub-fractions with 70% inhibition (p < 0.0001). The compounds responsible for the activity were purified, and their structures were established as rosmarinic acid, and methyl rosmarinate by spectroscopic methods. IC50 values of rosmarinic acid, and methyl rosmarinate were calculated as 0.21 and 0.02 ?M, respectively. In conclusion, the in vitro anti-inflammatory potential of S. palaestina was associated to rosmarinic acid, and methyl rosmarinate, for the first time to the best of our knowledge. © 2021 SAABArticle Citation - WoS: 20Citation - Scopus: 18Control of Polyphenol Oxidase in Whole Potatoes by Low Temperature Blanching(Springer Verlag, 2002) Yemenicioğlu, AhmetRusset Burbank potatoes can be blanched up to 60 min at 50 °C without any loss in firmness and without appearance of browning on their peels, eyes or infected areas. Low temperature blanching (LTB) for 45 min did not cause a significant reduction in crude polyphenol oxidase (PPO) activity (12%). However, when heating time was extended to 60 min, the activity and specific activity of the enzyme were reduced by 27-45% and 22-43% respectively. The remaining enzyme extracted from heated potatoes was partially purified 3.3-3.75-fold by 0-95% ammonium sulphate precipitation and dialysis, and its kinetic parameters were determined. The comparison of the kinetic parameters of PPO in control (Km=10.3 mM and Vmax/Km=0.15) and in 60 min heated potatoes (Km=13 mM and Vmax/Km=0.054) indicated the reduced affinity of the remaining enzyme to its substrate. Thus, LTB at 50 °C for 60 min not only inactivated part of the PPO activity but also reduced the kinetic capacity of remaining enzyme. Extending heating time to 75 min caused the appearance of slight browning on the peels and eyes of potatoes and reduced their firmness. The observed browning was due to the sharp drop in the Km that caused the activation of the PPO. Heating at 50 °C did not affect lipoxygenase activity, but the Km of the enzyme dropped from 0.4 to 0.15 mM and the enzyme became kinetically more reactive at low substrate concentrations. Covalently bound pectin methylesterase considerably activated (38%) by heating and this caused the drop of pH in potato tissues.