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    An unusual pregnane derivative and dibenzylbutyrolactone lignans from Centaurea sclerolepis
    (Polish Chemical Soc, 2006) Erdemgil, Z; Rosselli, S; Maggio, AM; Raccuglia, RA; Celik, S; Michalska, K; Kisiel, W
    [Anstract Not Available]
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    Essential oil of Stachys aleurites from Turkey
    (Pergamon-Elsevier Science Ltd, 2005) Flamini, G; Cioni, PL; Morelli, I; Celik, S; Gokturk, RS; Unal, O
    The essential oil obtained from the aerial parts of the Turkish endemism Siachys aleurites (Lamiaceae) has been studied. The main constituents were sesquiterpene hydrocarbons: beta-caryophyllene (33.7%), bicyclogermacrene (14.5%) and germacrene D (9.6%). The main monoterpene was alpha-pinene (8.4%). Some chernotax(o)nomical considerations have been provided. (C) 2004 Elsevier Ltd. All rights reserved.
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    Essential oils of Phlomis leucophracta, Phlomis chimerae and Phlomis grandiflora var. grandiflora from Turkey
    (Pergamon-Elsevier Science Ltd, 2005) Celik, S; Gokturk, RS; Flamini, G; Cioni, PL; Morelli, I
    The essential oils of three species of Phlomis from Turkey, Phlomis leueophracta, Phlomis chimerae and Phlomis grandiflora var. grandiflora have been studied. The main constituents of P. leucophracta essential oil were beta-caryophyllene (20.2%), alpha-pinene (19.2%) and limonene (11.0%). This species also contained three diterpene derivatives, 15-isopimaradiene, manoyl oxide and epi-13-manoyl oxide that summed 1.4%. In P. chimerae the principal compounds were beta-caryophyllene (31.6%), alpha-pinene (11.0%), germacrene D (6.1%), limonene (5.5%) and linalool (4.7%). In P. grand flora var. grand flora, germacrene D (45.4%), beta-caryophyllene (22.8%) and bicyclogermacrene (4.9%) were among the principal derivatives. (c) 2005 Elsevier Ltd. All rights reserved.
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    Isolation, structure elucidation and bioactivity of schischkiniin, a unique indole alkaloid from the seeds of Centaurea schischkinii
    (Pergamon-Elsevier Science Ltd, 2005) Shoeb, M; Celik, S; Jaspars, M; Kumarasamy, Y; MacManus, SM; Nahar, L; Paul, KTLD
    Reversed-phase HPLC analysis of the methanol extract of the seeds of Centaurea schischkinii afforded a novel indole alkaloid, named schischkiniin (1), together with four lignans, arctiin (2), matairesinoside (3), matairesinol (4), and arctigenin (5), and three flavonoids, astragalin (6), afzelin (7) and apigenin (8). While the structure of schiskiniin (1) was established unequivocally by UV, HRFABMS and a series of ID and 2D NMR analyses, all known compounds were readily identified by comparison of their spectroscopic data with literature data. The free radical scavenging properties of these compounds were assessed using the DPPH assay, and their general toxicity and cytotoxicity were evaluated, respectively, by brine shrimp lethality and MTT cytotoxicity assays with CaCo-2 colon cancer cell lines. Arctigenin (5) exhibited promising in vitro anticancer activity (IC50=7 mu M) while with schischkiniin (1) the activity was of moderate level (IC50 = 76 mu M). (c) 2005 Elsevier Ltd. All rights reserved.
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    Two acylated flavonoid glycosides from Stachys bombycina, and their free radical scavenging activity
    (Govi-Verlag Pharmazeutischer Verlag Gmbh, 2005) Delazar, A; Celik, S; Göktürk, RS; Unal, O; Nahar, L; Sarker, SD
    Preparative reversed-phase HPLC analysis of the methanol extract of the aerial parts of Stachys bombycina (Lamiaceae) afforded two acylated flavonoids glycosides, chrysoeriol 7-O[6-O-acetyl-beta-D-allopyranosyl]-(1 --> 2)-beta-D-glucopyranoside (1) and apigenin 7-O-beta-D-(6-p-coumaroyl)-glucopyranoside (2), the former being a new natural product. The structures of these compounds were elucidated unambiguously by UV spectroscopic analyses using shift reagents, ESIMS, and 1D and 2D NMR spectroscopic techniques. The free radical scavenging activity of 1 and 2 compounds were assessed by DPPH assay, and the RC50 values were 1.25 x 10(-2) and 7.69 x 10(-4) mg/mL, respectively.
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    Volatile components of Centaurea calcitrapa L. and Centaurea sphaerocephala L. ssp sphaerocephala, two Asteraceae growing wild in Sicily
    (Wiley, 2006) Senatore, F; Landolfi, S; Celik, S; Bruno, M
    The volatile components of the flowerheads of Centaurea calcitrapa L. (C.c.) and Centaurea sphaerocephala L. ssp. sphaerocephala (C.s.) were obtained by hydrodistillation and identified by GC and GC-MS. Altogether 96 components were identified, 66 in C. calcitrapa and 68 in C. spaerocephala, mostly fatty acids (32.8%, C.c. and 44.2%, C.s.) and hydrocarbons (32.3%, C.c. and 15.9%, C.s.). 9,12-Octadecadienoic acid (15.8%, C.c.) and hexadecanoic acid (30.7%, C.s.) were the most abundant fatty acids; tricosane (8.0%, C.c.) and heptacosane (4.9%, C.s.) were the main hydrocarbons. Sesquiterpenes were also present as hydrocarbons (10.1% for 14 components in C.c. and 9.2% for 13 components in C.s.) and as oxygen-containing sesquiterpenes (2.0% for four components in C.c. and 13.6% for nine components in C.s.). Copyright (c) 2005 John Wiley & Sons, Ltd.