Browsing by Author "Ulubelen, Ayhan"

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Antioxidant and Anticholinesterase Constituents of Salvia Poculata
(Tubitak Scientific & Technological Research Council Turkey, 2009) Kolak, Ufuk; Hacibekiroglu, Isil; Ozturk, Mehmet; Ozgokce, Fevzi; Topcu, Guelacti; Ulubelen, Ayhan
Two triterpenoids, namely 2 alpha,3 alpha-dihydroxy-24-nor-4(23), 12-oleanadien-28-oic acid (1) and ursolic acid (2); 4. avonoids, namely 5-hydroxy-7,4'-dimethoxyflavone (3), cirsimaritin (4), eupatilin (5), and salvigenin (6); a diterpenoid, namely sclareol (7); and a steroid, namely beta-sitosterol (8), were isolated from the aerial parts of Salvia poculata Nab., a Turkish endemic Salvia species. Total phenolic and flavonoid contents of the crude extract were determined as pyrocatechol and quercetin equivalents, respectively. The antioxidant activity of the crude extract and the isolated compounds (2-8) was established using beta-carotene bleaching, superoxide anion radical, and ABTS cation radical scavenging activity. In addition, the anticholinesterase activity of the crude extract and the isolated compounds (2-8) against the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) was determined. The phytochemistry and antioxidant and anticholinesterase activities of S. poculata were investigated for the first time in this study. The crude extract of S. poculata exhibited a significant antioxidant effect as well as butyrylcholinesterase inhibitory activity. Ursolic acid (2) and cirsimaritin (4) possessed high butyrylcholinesterase inhibitory activity.
Norditerpene Alkaloids From Delphinium Linearilobum and Antioxidant Activity
(Pergamon-elsevier Science Ltd, 2006) Kolak, Ufuk; Ozturk, Mehmet; Ozgokce, Fevzi; Ulubelen, Ayhan
From the roots of Delphinium linearilobum (Trautv.) N. Busch two new norditerpene alkaloids linearilobin and linearilin, and the known alkaloids lycoctonine, 14-acetyltalatizamine, browniine, cammaconine, talatizamine, and cochlearenine were isolated. Spectroscopic techniques were used for structure determination. Antioxidant activity was performed by DPPH and metal chelating activity assays. (c) 2006 Elsevier Ltd. All rights reserved.
Phytochemical Investigation of Leontice Leontopetalum L. Subsp Ewersmannii With Antioxidant and Anticholinesterase Activities
(Acg Publications, 2011) Kolak, Ufuk; Hacibekiroglu, Isil; Boga, Mehmet; Ozgokce, Fevzi; Unal, Murat; Choudhary, M. Iqbal; Ulubelen, Ayhan
Two known quinolizidine alkaloids, lupanine and leontiformidine, were isolated from the tubers of L. leontopetalum subsp. ewersmannii. Lupanine having the highest inhibition of lipid peroxidation at 100 mu g/mL among the tested samples indicated almost the same ABTS cation radical scavenging activity with BHT, alpha-tocopherol and (+)-catechin at the same concentration. Lupanine and the alkaloidal extract showed almost the same butyrylcholinesterase inhibitory activity with galantamine at 200 mu g/mL.