Ayhan Ulubelen

Istanbul University, İstanbul, Istanbul, Turkey

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Publications (148)364.15 Total impact

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    ABSTRACT: The hexane and dichloromethane extracts, obtained by re-extraction of the methanol extract of Salvia fruticosa Mill., afforded 7 diterpenoids (carnosol, carnosic acid, carnosic acid 12-methyl ether, rosmadial, isorosmanol, ferruginol, and manool), 4 triterpenoids (�alpha-amyryltetracosanoate, oleanolic acid, ursolic acid, and erythrodiol), a steroid (3-acetylsitosterol), and a flavone (salvigenin). The galls (apples) of the collected plant were separately extracted with hexane to a�ord fatty acids composed mainly of oleic acid (29%), palmitoleic acid (29%), and stearic acid (23.20%), which exhibited high anticholinesterase activity, particularly against BChE. The essential oil, obtained from the aerial parts of the plant, exhibited high AChE inhibitory activity, consisting of mainly 1,8-cineol (58.89%). The antioxidant activity according to 6 complementary tests and anticholinesterase potential of the methanol extracts and triterpenoids �alpha-amyryltetracosanoate, oleanolic acid, ursolic acid, and sitosterol acetate were also investigated, and methanol extract exhibited the highest antioxidant and anticholinesterase activity, surpassing the other tested extracts and pure compounds
    Turkish Journal of Chemistry 07/2013; DOI:10.3906/kim-1303-25 · 1.12 Impact Factor
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    Ayhan Ulubelen · Ufuk Kolak · Mehmet Boğa ·

    Records of Natural Products 09/2012; 6(3-6):194-211. · 0.87 Impact Factor
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    ABSTRACT: 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 μg/mL among the tested samples indicated almost the same ABTS cation radical scavenging activity with BHT, a-tocopherol and (+)-catechin at the same concentration. Lupanine and the alkaloidal extract showed almost the same butyrylcholinesterase inhibitory activity with galantamine at 200 μg/mL.
    Records of Natural Products 03/2011; 5(4-5):309-313. · 0.87 Impact Factor
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    Ufuk Kolak · Mehmet Boğa · Emine Akalın-Uruşak · Ayhan Ulubelen ·
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    ABSTRACT: The methanol extract of Plantago major subsp. intermedia (Gilib.) Lange afforded 4 known compounds, namely isomartynoside (1), 10-hydroxymajoroside (2), beta-sitosterol (3), and ursolic acid (4). Their structures were established by spectroscopic methods. After determination of the total phenolic and flavonoid contents of the methanol extract, the antioxidant potentials of the crude extract and isolated compounds 1-4 were determined by beta-carotene bleaching, DPPH free radical and ABTS cation radical scavenging, and cupric reducing antioxidant capacity methods. The methanol extract, rich in phenolic contents, indicated the same DPPH free radical scavenging activity (72% inhibition) as a standard compound, butylated hydroxytoluene, at 100 mu g/mL. Isomartynoside (1), a phenylpropanoid glycoside, showed the best inhibition of lipid peroxidation, ABTS cation radical scavenging activity, and cupric reducing antioxidant capacity among the tested samples. The anticholinesterase effects of the methanol extract and isolated compounds 1-4 were established using the Ellman method. A triterpenic acid, ursolic acid (4), exhibited moderate acetyl- (54.01 +/- 0.82%) and butyryl-cholinesterase (68.74 +/- 0.36%) inhibitory activity at 200 mu g/mL. Isomartynoside (1) was isolated here for the first time from a Plantago species; the antioxidant and anticholinesterase activities of P. major subsp. intermedia and compounds 1-2 were not previously determined.
    Turkish Journal of Chemistry 02/2011; 35(35):637-645. DOI:10.3906/kim-1102-990 · 1.12 Impact Factor
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    ABSTRACT: Seven diterpenoid alkaloids: delcosine(1), delsoline(2), gigactonine(3), lycoctonine(4), takaosamine(5), atisine(6) and hetisinone(7) have been isolated from the aerial parts of Consolida regalis subsp. paniculata var. paniculata. The presence of compounds 1,2,5,6 and 7 in this plant has not been previously reported.
    ChemInform 07/2010; 32(31). DOI:10.1002/chin.200131210
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    ABSTRACT: The phytochemical and biological studies carried out on Salvia species showed that their extracts and constituents have various biological activities. The aim of this study was the isolation of diterpenoids from the roots of Salvia barrelieri Ettling and the determination of the antioxidant activity. Chromatographic methods were used for fractionation and isolation, respectively. Structure elucidation was established by spectroscopic methods. Five antioxidant assays were performed. Three new abietane diterpenoids barreliol, royleanone 12-methyl ether and 7-epi-salviviridinol, and six known diterpenoids, with a known dammarane triterpenoid, pyxinol were isolated. The absolute stereochemistry of pyxinol was confirmed by X-ray analysis. Taxodione exhibited the highest antioxidant activity among the tested compounds.
    Phytochemical Analysis 07/2009; 20(4):320-7. DOI:10.1002/pca.1130 · 2.34 Impact Factor
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    ABSTRACT: The essential oil from the aerial parts of Stachys cretica L. subsp. smyrnaea Rech. fil. (Lamiaceae), endemic to Turkey, was investigated by using GC and GC-MS. Thirty-four of 37 components, represented 99.7% of the total oil, were identified. The major components of the essential oil were trans-beta-caryophyllene (51.0%), germacrene-D (32.8%), a-humulene (3.1%), delta-cadinene (2.1%) and delta-elemene (2.1%). The antimicrobial activity of the essential oil, trans-beta-caryophyllene and five different extracts of the aerial parts of S. cretica L. subsp. smyrnaea were investigated by the standard disc diffusion method. The essential oil and trans-beta-caryophyllene exhibited antibacterial and antifungal activities. The activity increased with increasing concentrations of the essential oil and the extracts. The essential oil showed antimicrobial activity, particularly against Pseudomonas aeruginosa and Bacillus subtilis. The extracts exhibited either moderate or no activity.
    Natural product communications 02/2009; 4(1):109-14. · 0.91 Impact Factor
  • Ayhan Ulubelen · Ufak Kolak ·
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    ABSTRACT: Recently, we have investigated Aconitum cochleare Woroschin and obtained three new alkaloids cochleareine, acoleareine from the aerial parts of the plant and cochleareinine from the roots. Cochlearenine exhibited antioxidant activity against DPPH free radical scavenging assay. The cardio active effect of has also have been studied on isolated heart preparations. Two new norditerpene alkaloids linearilobin and linearilin were isolated from Delphinium linearilobum (Trautv.) N. Busch. The antioxidant activity was established by using DPPH and metal chelating activity tests.
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    ABSTRACT: Two triterpenoids, namely 2 α ,3 α -dihydroxy-24-nor-4(23),12-oleanadien-28-oic acid (1) and ursolic acid (2); 4 flavonoids, namely 5-hydroxy-7,4'-dimethoxyflavone (3), cirsimaritin (4), eupatilin (5), and salvigenin (6); a diterpenoid, namely sclareol (7); and a steroid, namely β -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 β -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.
  • Ayhan Ulubelen · Gülaçti Topçu · Hee-Byung Chai · John M. Pezzuto ·
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    ABSTRACT: Ten diterpenoids [6a-hydroxysalvinolone (1), 6a-hydroxytaxodone (2), aethiopinone (3), microstegiol (4), ferruginol (5), saprorthoquinone (6), 11,12-dioxoabieta-8,13-diene (7), taxodione (8), hypargenin A (9), hypargenin D (10)] and three triterpenoids [lupeol 3-acetate, d-oleanol 3-acetate and ß-sitosterol] were isolated from the roots of Salvia hypargeia, a plant endemic to Turkey. The crude extract and compounds 1-2, 5-10 were tested against a panel of human cancer cell lines [human breast cancer (BC 1), human lung cancer (LU 2), human colon cancer (COL 2), human epidermoidal carcinoma in mouth (KB), vinblastine-resistant KB-VI, hormone-dependent human prostate cancer (LNCaP)] as well as P388 and ASK cells in culture. The crude extract was active in all of the test systems, except KB. Isolates 1 and 8 were also found to mediate a generalized cytotoxic response.
    Pharmaceutical Biology 09/2008; 37(2):148-151. DOI:10.1076/phbi. · 1.24 Impact Factor
  • Gulacti Topcu · Ayhan Ulubelen ·
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    ABSTRACT: In our continuing studies on Lamiaceae family plants including Salvia, Teucrium, Ajuga, Sideritis, Nepeta and Lavandula growing in Anatolia, many terpenoids, consisting of over 50 distinct triterpenoids and steroids, and over 200 diterpenoids, several sesterterpenoids and sesquiterpenoids along with many flavonoids and other phenolic compounds have been isolated. For Salvia species abietanes, for Teucrium and Ajuga species neo-clerodanes for Sideritis species ent-kaurane diterpenes are characteristic while nepetalactones are specific for Nepeta species. In this review article, only some interesting and different type of skeleton having constituents, namely rearranged, nor- or rare diterpenes, isolated from these species will be presented. For structure elucidation of these natural diterpenoids intensive one- and two-dimensional NMR techniques (1H, 13C, APT, DEPT, NOE/NOESY, 1H–1H COSY, HETCOR, COLOC, HMQC/HSQC, HMBC, SINEPT) were used besides mass and some other spectroscopic methods.
    ChemInform 08/2007; 38(34):57-73. DOI:10.1016/j.molstruc.2006.12.001
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    ABSTRACT: The methanol extract of Salvia macrochlamys Boiss. and Kotschy was fractionated on a silica gel column to yield a group of terpenic compounds. After separation and cleaning, seven known and three new terpenoid compounds were isolated, and their structures were elucidated by spectroscopic methods, including intensive NMR and MS studies. The crude extract was tested in five different systems for antioxidant activity. The extract and monogynol A (1) and its three derivatives (2-4) were found to be highly active in a metal chelating test system on ferrous ions.
    02/2007; 7(7):195-208.
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    ABSTRACT: Acetone and methanol extracts of the fruits of Pistacia terebinthus L. subsp. terebinthus L. were studied for their antioxidant activity by investigating their total phenolic and flavonoid contents, β-carotene bleaching potential, DPPH radical scavenging effect, scavenging activity on superoxide anion radical, reducing power, and metal chelating effect on ferrous ion. Both extracts showed very similar chemical profile by checking on TLC plates, and exhibited high scavenging activity on superoxide anion radical and DPPH radical. Due to these similarities they were combined and fractionated on a silica gel column for their constituents, and the most active three fractions in DPPH assay were purified to afford a new flavone 6′-hydroxyhypolaetin 3′-methyl ether (1) besides a group of known flavonoids apigenin, luteolin, luteolin 7-O-glucoside, quercetin, quercetagetin 3-methyl ether 7-O-glucoside, isoscutellarein 8-O-glucoside. Their structures were established by UV, UV shift reagents, and 1H NMR spectroscopic techniques. Antioxidant activity of the new flavone was investigated by β-carotene bleaching and DPPH radical scavenging activity methods, and it showed a high activity in the first system, but not so good in the latter.
    Food Chemistry 01/2007; 103(3-103):816-822. DOI:10.1016/j.foodchem.2006.09.028 · 3.39 Impact Factor
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    Ufuk Kolak · Mehmet Oztürk · Fevzi Ozgökçe · Ayhan Ulubelen ·
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    ABSTRACT: 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.
    Phytochemistry 11/2006; 67(19):2170-5. DOI:10.1016/j.phytochem.2006.06.006 · 2.55 Impact Factor
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    Ufuk Kolak · Mehmet Öztürk · Fevzi Özgökçe · Ayhan Ulubelen ·

  • Ayhan Ulubelen · Gulacti Topcu · Ufuk Kolak ·
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    ABSTRACT: There are about 200 genera in Labiatae family in the world, whereas in Turkish flora 45 genera are present. A literature survey revealed that only 10 genera are extensively investigated for the flavonoidal compounds, some work were done about 23 genera, but the rest had no flavonoidal investigation. The biological activities of flavonoids were also studied together with their structural studies. The most studied genus for the biological activities is Scutellaria. Baicalein, baicalin and wogonin showed a number of important activities.
    Studies in Natural Products Chemistry 12/2005; 30(30):233-302. DOI:10.1016/S1572-5995(05)80035-3
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    ABSTRACT: The vascular effect of salvigenin (6-hydroxyapigenin 6,7,4' -trimethyl ether), a natural flavone, was investigated in comparison with another flavone, 6-hydroxyluteolin 6,7,3',4' -tetramethyl ether in rat aortic rings. Cumulative addition of their increasing concentrations (10(-9)-10(-4)M) produced graded relaxations on rings precontracted with noradrenaline (10(-6) M) and KCl (40 mM). The maximal relaxations induced by flavones were similar, however, based on their pEC50 values salvigenin displayed a higher potency than 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether. Endothelium removal markedly reduced the relaxations to salvigenin while the responses to 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether were partially affected. In addition, a significant decrease was observed in maximal responsiveness and sensitivity to flavones in the presence of L-NOARG, a NO synthase inhibitor. The cyclooxygenase inhibitor indomethacin significantly inhibited the relaxations to salvigenin, but not altered the responses to 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether. Our results provide evidence that salvigenin is an effective flavone in causing vasorelaxation which appears to be mediated by endothelium derived NO and prostacyclin. Whereas, the other flavone, 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether induced relaxant responses are partially endothelium, presumably NO mediated.
    Vascular Pharmacology 11/2005; 43(4):220-6. DOI:10.1016/j.vph.2005.07.002 · 3.64 Impact Factor
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    Ufuk Kolak · Gülaçtı Topç U · Irtek Oz · Gülte O Uk · Ayhan Ulubelen ·
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    ABSTRACT: From the roots of Salvia blepharochlaena Hedge and Hub. Mor. 4 triterpenoids, 4 steroids, 6 diterpenoids, and an aromatic ester were isolated. The structures of these compounds were established by spectroscopic methods. Formosanolide was isolated for the first time from the genus Salvia.
    Turkish Journal of Chemistry 01/2005; 29(2):177-186. · 1.18 Impact Factor
  • Ayhan Ulubelen · Gülaçti Topcu · Ertan Tuzlaci ·
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    ABSTRACT: Three new diterpenoids, 6-oxoroyleanone-18-oic acid [1], 6-oxo-12-methylroyleanone-18-oic acid [2], and horminone-18-oic acid [3], and a new linear sesquiterpene, salvinine [4], together with a group of known aromatic acids, were isolated from the aerial parts of Salvia divaricata.
    Journal of Natural Products 06/2004; 55(10). DOI:10.1021/np50088a020 · 3.80 Impact Factor

  • Journal of Natural Products 06/2004; 46(4). DOI:10.1021/np50028a037 · 3.80 Impact Factor

Publication Stats

2k Citations
364.15 Total Impact Points


  • 1979-2013
    • Istanbul University
      • • Department of Analytical Chemistry
      • • Department of Pharmacognosy
      • • Department of Chemistry
      İstanbul, Istanbul, Turkey
  • 2001
    • Athens State University
      Athens, Alabama, United States
  • 1998
    • University of Peshawar
      Peshawar, Khyber Pakhtunkhwa, Pakistan
  • 1997-1998
    • TUBITAK Marmara Research Center
      Marmara, Balıkesir, Turkey
    • Ankara University
      • Faculty of Pharmacy
      Engüri, Ankara, Turkey
  • 1995
    • The Scientific & Technological Research Council of Turkey
      Guebze, Kocaeli, Turkey
    • Universidad de La Laguna
      San Cristóbal de La Laguna, Canary Islands, Spain
  • 1994
    • University of Illinois at Chicago
      • Department of Medicinal Chemistry and Pharmacognosy
      Chicago, Illinois, United States
  • 1988
    • Marmara University
      İstanbul, Istanbul, Turkey
  • 1980
    • University of Texas at Austin
      • Department of Botany
      Austin, Texas, United States