Person: DOĞAN, AHMET
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DOĞAN
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AHMET
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Publication Metadata only Phenolic components and assessment of biological properties of Tchihatchewia isatidea Boiss. extracts: Docking and functional approaches for designing novel products(PERGAMON-ELSEVIER SCIENCE LTD, 2018) DOĞAN, AHMET; Zengin, Gokhan; Abdallah, Hassan H.; Dogan, Ahmet; Mollica, Adriano; Aumeeruddy-Elalfi, Zaahira; Mahomoodally, Mohamad FawziThe potentiality of bioactive phenolic compounds may result in plant extracts having multiple biological activities. The aim of this study was to investigate into the biological activities of the methanolic, ethyl acetate, and water extracts of Tchihatchewia isatidea Boiss, an endemic medicinal plant of Turkey. The phenolic compositions of the extracts were confirmed using RP-HPLC. Extracts were screened for their potential antioxidant through a panoply of assays; their anti-diabetic potential, and plausible inhibitory activity against tyrosinase and acetylcholinesterase. Molecular modelling methods were also used to assess the docking properties of phenolic compounds on tyrosinase. The major and most abundant compounds were rosmarinic acid (570 +/- 14 mu g/g extract in the methanolic extract), ferrulic acid (336 +/- 6 mu g/g extract in the methanolic extract), (+)-catechin (340 +/- 4 mu g/g extract in the water extract), apigenin (182 +/- 4 mu g/g extract in the methanolic extract), and epicatechin (188 12 g/g extract in the water extract). Radical scavenging, reducing capacity, and metal chelating activities were detected in the extracts, with preponderance activity observed in the methanolic extract. In conclusion, the potential clinical applications observed during this study may provide new insights into the molecular aspect particularly for neuroprotective and anti-diabetic mechanisms involving oxidative stress.Publication Metadata only Chemical composition and bio-functional perspectives of Erica arborea L. extracts obtained by different extraction techniques: Innovative insights(ELSEVIER, 2019) DOĞAN, AHMET; Zengin, Gokhan; Cvetanovic, Aleksandra; Gasic, Uros; Stupar, Alena; Bulut, Gizem; Senkardes, Ismail; Dogan, Ahmet; Seebaluck-Sandoram, Roumita; Rengasamy, Kannan R. R.; Sinan, Kouadio Ibrahime; Mahomoodally, Mohamad FawziErica arborea L., also known as Estrella Gold, is traditionally used for several purposes. In this research, five different extraction techniques: accelerated solvent extraction (ASE), microwave-assisted extraction (MAE), maceration (MAC), soxhlet (SOE) and ultrasound-assisted extraction (UAE) were used to compare the total phenolic, flavonoids, total antioxidant activity and enzymatic activities of E. arborea extracts obtained different extraction techniques. The total phenolic and flavonoid contents were in the order of ASE > MAE > SOE > MAC > UAE. All extracts showed antioxidant, anticholinesterase, anti-tyrosinase and anti-diabetic activities. A highly sensitive method using ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS) has been used for the qualitative analysis of obtained extracts. Seventy-two polyphenolic compounds were identified in all extracts. However, 20 components were quantified among the extracts. ASE was found to be a better extraction technique as compared to the other extraction techniques. E. arborea can be exploited in the discovery of bioactive natural products for the treatment of Alzheimer's disease, diabetes and pigmentation problems.Publication Metadata only Chemical composition of endemic Stachys subnuda Montbret & Aucher ex Benth. essential oil and its anti-inflammatory and antioxidant activities(TAYLOR & FRANCIS INC, 2019) DOĞAN, AHMET; Sen, Ali; Kurkcuoglu, Mine; Bitis, Leyla; Dogan, Ahmet; Baser, Kemal Husnu CanThe essential oil of aerial parts of Stachys subnuda Montbret & Aucher ex Benth (S. subnuda) was analyzed by gas chromatography (GC) and GC/mass spectrometry (MS). Anti-inflammatory activity was evaluated by lipoxygenase inhibition assay. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) assays. Sixty-two constituents, comprising 97.1% of the total essential oil composition, were identified. Phytol (25.2%), beta-caryophyllene (11.2%), germacrene D (6.9%), and hexadecanoic acid (6.9%) were the major compounds of aerial part essential oils of S. subnuda. The essential oil showed significant radical scavenging activity with 50% inhibition (IC50) values of 0.124 and 0.204 mg/mL for ABTS and DPPH radicals, respectively. The essential oil exhibited moderate anti-inflammatory activity with an IC50 value of 0.419 mg/mL. The results indicated that S. subnuda essential oil had good anti-inflammatory and antioxidant activity. Also, this is first study on chemical composition, anti-inflammatory and antioxidant activity of S. subnuda essential oil.Publication Metadata only HPLC-MS/MS-based metabolic profiling and pharmacological properties of extracts and infusion obtained from Amelanchier parviflora var. dentata(ELSEVIER SCIENCE BV, 2018) DOĞAN, AHMET; Zengin, Gokhan; Diuzheva, Alina; Jeko, Jozsef; Cziaky, Zoltan; Bulut, Gizem; Dogan, Ahmet; Haznedaroglu, Mehmet Zeki; Rengasamy, Kannan R. R.; Lobine, Devina; Bahadori, Mir Babak; Mahomoodally, Mohamad FawziArnelanchierparviflora var. dentata is an endemic medicinal plant traditionally consumed to treat stomach pain, cardiovascular diseases, and urinary tract infections in Turkey's folk medicine. Although Amelanchier genus is an excellent source of phytochemicals with a panoply of biological activities, no report has been made available on Amelanchier parviflora var. dentata. Thus, the metabolic profiles of methanol, ethyl acetate, and water extracts were obtained using HPLC-MS/MS. Besides, the pharmacological properties such as antioxidant activity and enzyme inhibition effects against acetyl/butyrylcholinesterase, tyrosinase, alpha-amylase, and alpha-glucosidase were evaluated. In total, 62, 38, and 16 metabolites were Identified from the methanolic, water, and ethyl acetate extracts, respectively. The identified metabolites belong to anthocyanins, phenolic acids, and flavonoids. The tested extracts exhibited different enzyme inhibitory activity against cholinesterases (acetylcholinesterase: 0.52-2.47 mg GEs/g extract and butyrylcholinesterase: 0.47-3.59 mg GEs/g extract), tyrosinase (19,0-145.54 mg KAEs/g extract), alpha-amylase (0.23-1.10 mmol ACEs/g extract), and alpha-glucosidase (8.89-9.92 mmol ACEs/ g extract). Evidence from the present study supports the necessity for more research in an endeavor to discover biologically active secondary metabolites from A. parviflora to manage specific ailments.Publication Metadata only Characterization of Phenolic Constituents and Pharmacological Activity of Achillea vermicularis(INDIAN PHARMACEUTICAL ASSOC, 2019) DOĞAN, AHMET; Taskin, T.; Balkan, I. E.; Tankin, D.; Dogan, A.The aim of the present study was to compare for the first time, the antiinflammatory, antioxidant and antiurease activities of 15 different extracts of Achillea vermicularis, which were obtained from three extraction methods using five different solvents. Phenolic contents in chloroform extract showed strong antiinflammatory and antioxidant activity and were analysed by high-performance liquid chromatography with diode-array detection and confirmed by liquid chromatography quadrupole time-of-flight mass spectrometry. The active phenolic compounds in chloroform extracts were identified as chlorogenic acid, caffeic acid, rutin, dicaffeoylquinic acid, naringenin, quercetagetin 3,6-dimethyl ether, and 8-hydroxysalvigenin. All these compounds except caffeic acid were detected for the first time in Achillea vermicularis. These results indicated that chloroform extract of the plant possessed a high potential to be used as a natural source in food and pharmaceutical industry.Publication Metadata only Turkish folk medicinal plants, IX: Ovacik (Tunceli) [Türkiye'nin halk ilacı bitkileri, IX: Ovacık (Tunceli)](Marmara University, 2010) DOĞAN, AHMET; Tuzlaci E., Doǧan A.The aim of this study was made to reveal the plants used as traditional folk medicine in Ovaci{dotless}k (Tunceli). For this purpose, the field works have been done between May 2007-May 2008 in April, May, June and July lasting for 30 days, in total. During this research all the settlement centers (including 33 villages) have been visited, the specimens of the plants used as folk remedies have been collected and the information such as local names, ailments treated or therapeutic effects, plant parts used, method of administration, dosage, duration of treatment have been recorded. The collected plant specimens are kept in the Herbarium of the Faculty of Pharmacy, Marmara University (MARE). As a result of identification of 76 plant specimens, 67 species used as a traditional folk medicine, have been determined. Among them 65 species are wild and 2 species are cultivated plants. These plants and their local usage in treatment are presented in a table in the text. It was found out that the plants recorded in Ovaci{dotless}k are mostly used for cold, diabetes and wound.Publication Metadata only Essential oil composition of different parts of Tanacetum cilicicum (Boiss.) Grierson(Badebio Biotechnololgy Ltd, 2020) DOĞAN, AHMET; Şen A., Kürkçüoğlu M., Bitiş L., Doğan A., Başer K.H.C.The aim of this study was to investigate and compare the chemical composition of essential oils obtained by Clevenger-type apparatus from capitula (TCC) and aerial parts including leaves and stems (TCA) of Tanacetum cilicicum (Boiss.) Grierson from Turkey. TCC and TCA essential oils were separately analysed by GC-FID and GC/MS. Forty and thirty-two compounds were identified, representing 99% and 94.4% of the oils of TCC and TCA essential oils, respectively. The main constituents of the oil of the TCC were camphor (28.8%), (E)-nerolidol (16.9%), trans-chrysanthenyl acetate (12.8%) and 1,8-cineole (8.9%), whereas the oil from TCA comprised mainly trans-chrysanthenyl acetate (22.2%), borneol (19.4%), camphor (11.2%), 1,8-cineole (10.2%) and (E)-nerolidol (9.2%). The results showed that TCC and TCA essential oils were rich in oxygenated monoterpenes and oxygenated sesquiterpenes. This study is the first to study the essential oil composition of different parts of Tanacetum cilicicum separately. Also, to the our best of our knowledge, (E)-nerolidol was found in the Tanacetum species as the major compound for the first time. © 2020, Badebio Biotechnololgy Ltd. All rights reserved.Publication Metadata only Anti-quorum sensing and anti-biofilm activities of Hypericum perforatum extracts against Pseudomonas aeruginosa(ELSEVIER IRELAND LTD, 2019) DOĞAN, AHMET; Dogan, Sule; Gokalsin, Baris; Senkardes, Ismail; Dogan, Ahmet; Sesal, N. CenkEthnopharmacological relevance: Hypericum perforatum L. (Hypericaceae) has been used as a traditional therapeutic for skin wounds, burns, cuts and stomach ailments including stomach ache, ulcers for a long time in many societies. Although many studies about its antibacterial properties can be found, there is a lack of studies about its quorum sensing inhibition properties, which effects bacterial vulnerability directly, on Pseudomonas aeruginosa. Aim of the study: Evaluation of anti-quorum sensing (anti-QS) and anti-biofilm activity of ethanol, methanol, acetone and ultra-sonicated extracts of Hypericum perforatum L. (HP) which is a well-known wound healer, against P. aeruginosa. Materials and methods: Aerial parts of HP were extracted with ethanol, methanol and acetone. In addition, separate extractions with ultrasonication were carried out with same solvents. Anti-QS activity tests with different doses of HP extracts were performed by employing biomonitor strains, of which the promoter of QS regulating and green fluorescent protein (GFP) genes were fusioned. For anti-biofilm activity, HP extracts were applied to wild type PAO1 strains and biofilm inhibition was quantified via crystal violet staining method. Results: HP's ethanol, methanol and acetone extracts (250 mu g/ml doses) inhibited LasIR signalling pathway up to 65.43%, 59.60%, 55.95% and same solvent extracts obtained with ultrasonication inhibited 71.33%, 64.47%, 57.35% respectively. Moreover, inhibition rates of Rh1IR pathway were 28.80%, 50.83%, 45.84% for ethanol, methanol, acetone extracts (250 mu g/ml doses) and 51.43%, 57.41%, 50.02% for ultrasonication extracts (250 mu g/ml doses), compared to untreated controls. In the experiments, ethanol, methanol, acetone and ultra-sonicated extracts of HP did not inhibit biofilm formation. Conclusions: This study shows that HP plant is capable for blocking of las and rhl QS systems of P. aeruginosa. However, it was observed that ethanol, methanol and acetone extract of the plant samples did not show anti-biofilm activity against P. aeruginosa. This led us to thinking that biofilm formation was caused via another pathway such as IQS or PQS. Further studies with isolated active compounds of HP might give a better understanding of the effects on biofilm formation of P. aeruginosa.Publication Metadata only Paeonia arietina and Paeonia kesrounansis bioactive constituents: NMR, LC-DAD-MS fingerprinting and in vitro assays(ELSEVIER SCIENCE BV, 2019) DOĞAN, AHMET; Sut, Stefania; Zengin, Gokhan; Dall'Acqua, Stefano; Gazdova, Marketa; Smejkal, Karel; Bulut, Gizem; Dogan, Ahmet; Haznedaroglu, Mehmet Zeki; Aumeeruddy, Muhammad Zakariyyah; Maggi, Filippo; Mahomoodally, Mohamad FawziPaeonia species have been valued for their ethnomedicinal uses in various countries and received much interest among the scientific community for their therapeutic properties, including anti-microbial, anti-inflammatory, anti-cancer, nephroprotective and hepatoprotective effects. The multiple phytother-apeutical applications of Paeonia species inspired us to establish the phytochemical fingerprint and to evaluate the biological properties of ethyl acetate, methanol, and aqueous extracts from the roots and aerial parts of two Paeonia species (P. arietina G. Anderson and P. kesrounansis Thiebaut). Phytoconstituents of P. arietina and P. kesrounansis extracts were analyzed using 1D and 2D NMR and LC-DAD-ESI-MS. The total content of phenolics (TPC) and flavonoids (TFC) in the extracts was also evaluated. The antioxidant activity was profiled using DPPH, ABTS, CUPRAC, FRAP, phosphomolybdenum, and metal chelation assays. Enzyme inhibitory properties were evaluated against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, alpha-amylase, and alpha-glucosidase. Phytochemical analysis of P. arietina and P. kesrounansis extracts showed the presence of galloyl esters of sugars, galloyl monoterpenes, and glycosylated flavonoids. The three solvent extracts presented different behavior in the bioassays. The highest antioxidant activity, tyrosinase and AChE inhibition were observed for the methanolic extract of the aerial parts of P. kesrounansis. In addition, the ethyl acetate extracts of the aerial parts of both plants were the most effective inhibitors of alpha-amylase. The highest BChE inhibition was observed for root methanolic extract of P. kesrounansis while the root ethyl acetate extract of P. arietina exerted the strongest inhibition of alpha-glucosidase. Methanol extract of P. kesrounansis aerial parts presented the highest TPC, while TFC was greatest in the corresponding extract of P. arietina. Our findings can be considered as a starting point for future studies to further validate the effectiveness and safety profiles of these plants in folk medicine. (C) 2018 Elsevier B.V. All rights reserved.Publication Metadata only Modern and traditional extraction techniques affect chemical composition and bioactivity of Tanacetum parthenium (L.) Sch.Bip(ELSEVIER, 2020) DOĞAN, AHMET; Zengin, Gokhan; Cvetanovic, Aleksandra; Gasic, Uros; Stupar, Alena; Bulut, Gizem; Senkardes, Ismail; Dogan, Ahmet; Sinan, Kouadio Ibrahime; Uysal, Sengul; Aumeeruddy-Elalfi, Zaahira; Aktumsek, Abdurrahman; Mahomoodally, Mohamad FawziTanacetum parthenium (L.) Sch.Bip (TP), a flowering plant, is famous in traditional medicine to prevent migraine and headache. However, there is currently a dearth of studies to advocate the phytochemical profile and biological propensities of extracts prepared from this plant. This study endeavors to highlight the biological potential of TP extracts prepared by modern (ultrasound-UAE, microwave-MAE and accelerated-ASE extractions) and traditional (maceration and Soxhlet) extraction techniques. The chemical profile of the extracts was established via ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) technique. Sixty different polyphenolic compounds belonging to the classes of phenolic acids, flavonoid glycosides and flavonoid aglycones were recorded in the extracts. Additionally, the quantity of 17 components was measured using appropriate standards and it was found that the modern extraction gave extracts with the higher content of observed compounds than the traditional techniques. Evaluation of antioxidant activity was determined in vitro via five standard assays. The inhibitory potential of TP extracts against key enzymes implicated in the noncommunicable diseases such as diabetes (alpha-amylase and alpha-glucosidase), neurodegenerative diseases (acetyl- and butyrylcholinesterase) and skin diseases (tyrosinase), was assessed. Potent antioxidant ability of all TP extract was revealed with a predominance for the extracts yielded using the ASE method. This potent antioxidant activity of the extracts corroborated with the high phenolic (65.05 +/- 0.27 mg gallic acid equivalent (GAE)/g extract) and flavonoid contents (55A0 +/- 0.52 mg rutin equivalent (RE)/g extract). Tanacetum partheniwn extracts also showed significant alpha-glucosidase inhibitory activity (1.63-1.67 mmol acarbose equivalent (ACAE)/g extract) and moderate inhibition activity against a-amylase (0.51-0.56 mmol ACAE/g extract). The extracts also showed potent activity against cholinesterases and tyrosinase. This study tend to validate the use of TP extracts obtained by novel extraction techniques such as ASE, as potent bioactive extracts to be further studied for therapeutic bio-product development.