Browsing by Author "Orhan, Ilkay Erdogan"

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7-Acetoxyhorminone From Salvia Multicaulis Vahl. as Promising Inhibitor of 3-Hydroxy Coenzyme a (hmg-Coa) Reductase
(Mdpi, 2022) Yigitkan, Serkan; Ertas, Abdulselam; Salmas, Ramin Ekhteiari; Firat, Mehmet; Orhan, Ilkay Erdogan
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is a key enzyme involved in cholesterol biosynthesis and one of the most important targets for the treatment of hypercholesterolemia. A limited number of studies on the HMG-CoA reductase inhibitory potential of natural products are available. Thus, in the current study, we aimed to test the HMG-CoA reductase inhibitory capacity of extracts from the roots and aerial parts of Salvia multicaulis Vahl., through activity-guided isolation. Our findings revealed that the root extract prepared with dichloromethane-acetone (1:1) showed the highest inhibition (71.97 +/- 0.37%) at 100 mu g/mL. The extract was then initially fractionated by column chromatography and the obtained fractions were monitored by thin layer chromatography. Fractions which were similar to each other were combined and a total of 15 fractions were obtained. Further conventional chromatographic studies were carried out on the active fractions. Based on these fractions, 10 known compounds, comprising 9 terpenes and 1 steroid derivative in total, were isolated and their structures were verified by a combination of IT-TOF-MS, and 1D and 2D NMR techniques. According to the enzyme inhibition data of the identified compounds, 7-acetoxyhorminone exerted the highest inhibition (84.15 +/- 0.10%, IC50 = 63.6 +/- 1.21 mu g/mL). The molecular docking experiments on 7-acetoxyhorminone and horminone indicated that both compounds strongly bind to the active site of the enzyme.
Comprehensive Study of Chemical Composition and Biological Activity of Thymus Pubescens Boiss. Et Kotschy Ex Celak
(Elsevier, 2022) Yigitkan, Serkan; Akdeniz, Mehmet; Yener, Ismail; Seker, Zeki; Yilmaz, Mustafa Abdullah; Firat, Mehmet; Orhan, Ilkay Erdogan
The use of Thymus species amongst the public and their importance in the scientific world is increasing day by day. In addition to being consumed as tea and spice, Thymus species are used as folk medicine for respiratory, digestive, skin, circulatory, genital, nervous, visual and urinary diseases. In this study, it was aimed to examine the essential oil and ethanol extract of the root and aerial parts of Thymus pubescens Boiss. et Kotschy ex Celak in the terms of their biological activity and chemical content. The phenolic content of the species was determined by LC-MS/MS, while triterpenoid content, the chemical composition of the essential oil as well as flavour was determined by GC-MS. In addition, their antioxidant and cytotoxic activities, as well as acetyl- (AChE) and butyrylcholinesterase (BChE), urease, tyrosinase, elastase, collagenase, HMG-CoA reductase and angiotensin-converting enzyme (ACE) inhibitory activities were studied. Thymol (53.33%) was determined as the major component in the essential oil, while b-fenchyl alcohol (43.87%) was determined as the major component of the flavour. According to the LC-MS/MS and GC-MS results, it was found that especially the aerial parts of the species have a high amount of rosmarinic acid (3875.76 mg analyte/g extract), quinic acid (2392.55), naringenin (970.39), oleanolic (92785.96) and ursolic (63373.32) acids. The essential oil of T. pubescens species was observed to show high activity in four antioxidant assays, e.g. inhibition of lipid peroxidation, DPPH and ABTS radical scavenging activity as well as CUPRAC, while the ethanol extracts showed moderate antioxidant activity. In enzyme inhibition assays, the aerial parts exerted marked BChE, elastase, and collagenase inhibitory activities (92.43 +/- 1.28%, 42.59 +/- 0.56, and 48.61 +/- 0.39 at 100 mg/mL, respectively). On the other hand, AChE, urease, tyrosinase, HMG-CoA reductase and ACE inhibitory activities of all extracts were from low to moderate levels. In particular, the aerial parts of the species displayed a high cytotoxic effect (vitality%: 6.82 +/- 0.01 at 200 mg/mL) in breast cancer (MCF-7) cell line. Due to its remarkable antioxidant capacity, high content of rosmarinic, oleanolic, and ursolic acids and especially BChE, elastase, and collagenase inhibitory activity, T. pubescens has the potential for using in food supplements, food preservatives, cosmetics, and pharmaceutical industries.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.
Prospective Neurobiological Effects of the Aerial and Root Extracts and Some Pure Compounds of Randomly Selected Scorzonera Species
(Taylor & Francis Ltd, 2014) Senol, F. Sezer; Acikara, Ozlem Bahadir; Citoglu, Gulcin Saltan; Orhan, Ilkay Erdogan; Acqua, Stefano Dall'; Ozgokce, Fevzi
Context: Scorzonera L. species (Asteraceae) are edible and as medicinal plants are used for various purposed in folk medicine. Objective: The methanol extracts of the aerial parts and roots from 27 Scorzonera taxa were investigated for their possible neurobiological effects. Materials and methods: Inhibitory potential of the Scorzonera species was tested against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase (TYRO) at 100 mu gmL(-1) using ELISA microtiter assay. Antioxidant activity of the extracts was tested with radical scavenging activity, metal-chelation capacity, ferric-(FRAP), and phosphomolibdenum-reducing antioxidant power (PRAP) assays. Chlorogenic acid, hyperoside, rutin, and scorzotomentosin-4-O-beta-glucoside were also screened in the same manner. Total phenol and flavonoid quantification in the extracts were determined spectrophotometrically. Results: The aerial parts of Scorzonera pisidica (40.25 +/- 0.74%) and chlorogenic acid (46.97 +/- 0.82%) displayed the highest TYRO inhibition, while the remaining samples showed only trivial inhibition against cholinesterases (2.08 +/- 1.35% -25.32 +/- 1.37%). The same extract of S. pisidica was revealed to be the most potent in scavenging of all three radicals and FRAP assay. Discussion and conclusion: Out of 27 taxa, S. pisidica, in particular, may deserve further investigation for its neuroprotective potential.
Tyrosinase and Cholinesterase Inhibitory Potential and Flavonoid Characterization of Viola Odorata L. (Sweet Violet)
(Wiley, 2015) Orhan, Ilkay Erdogan; Senol, Fatma Sezer; Erdem, Sinem Aslan; Tatli, I. Irem; Kartal, Murat; Alp, Sevket
Inhibitory potential of the dichloromethane, ethyl acetate, ethanol, and aqueous extracts of Viola odorata L. (VO) was investigated against tyrosinase (TYR) and cholinesterases by microplate assays. The antioxidant activity was tested using six in vitro assays. Only the ethanol extract inhibited TYR (80.23 +/- 0.87% at 100 mu gmL(-1)), whereas none of them were able to inhibit cholinesterases. The extracts were more able to scavenge NO radical (31.98 +/- 0.53-56.68 +/- 1.10%) than other radicals tested, and displayed low to moderate activity in the rest of the assays. HPLC analysis revealed that the aqueous extract of VO contained a substantial amount of vitexin (18.81 +/- 0.047mgg(-1) extract), while the ethanol extract also possessed rutin (1.31 +/- 0.013mgg(-1) extract) and vitexin (4.65 +/- 0.103mgg(-1) extract). Furthermore, three flavonoids (rutin, isovitexin, and kaempferol-6-glucoside) were isolated from the ethanol extract. This is the first report on TYR inhibitory activity of VO as well as presence of vitexin and isovitexin in this species. Copyright (c) 2015 John Wiley & Sons, Ltd.