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Valentin A. Stonik - One of the best experts on this subject based on the ideXlab platform.
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diterpenoid hydroperoxides from the far eastern Brown Alga dictyota dichotoma
Australian Journal of Chemistry, 2009Co-Authors: Sergeevna Anna Kolesnikova, Ekaterina G Lyakhova, Anatoliy I. Kalinovsky, Sergei A Dyshlovoy, Pavel S. Dmitrenok, Valentin A. StonikAbstract:Two new compounds, dictyohydroperoxide 1 and hydroperoxyacetoxycrenulide 2, containing hydroperoxyl groups rarely found in Algal terpenoids were isolated from the Russian population of Brown Alga Dictyota dichotoma. The known compounds acetoxycrenulide 4 and squalene were also found in this Algal species for the first time. Some of the isolated compounds showed moderate cytoxicity against human cancer cell lines.
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diterpenes from the far eastern Brown Alga dictyota dichotoma
Phytochemistry, 2006Co-Authors: Sergeevna Anna Kolesnikova, Anatoliy I. Kalinovsky, Sergei N Fedorov, Larisa K Shubina, Valentin A. StonikAbstract:Abstract Two diterpenes, ent-erogorgiaene and (+)-1,5-cyclo-5,8,9,10-tetrahydroerogorgiaene, were isolated from the Russian Far-eastern population of the Brown Alga Dictyota dichotoma along with three previously known from this Alga terpenoids. In addition, pentadecane was the first time isolated as natural product from this species. The structures of all compounds and their stereochemistry were determined using 1D and 2D NMR ( 1 H– 1 H COSY, DEPT, HSQC, HMBC and NOESY), mass spectrometry, and optical rotation data.
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diterpenes from the far eastern Brown Alga dictyota dichotoma
Phytochemistry, 2006Co-Authors: Sergeevna Anna Kolesnikova, Anatoliy I. Kalinovsky, Sergei N Fedorov, Larisa K Shubina, Valentin A. StonikAbstract:Abstract Two diterpenes, ent-erogorgiaene and (+)-1,5-cyclo-5,8,9,10-tetrahydroerogorgiaene, were isolated from the Russian Far-eastern population of the Brown Alga Dictyota dichotoma along with three previously known from this Alga terpenoids. In addition, pentadecane was the first time isolated as natural product from this species. The structures of all compounds and their stereochemistry were determined using 1D and 2D NMR ( 1 H– 1 H COSY, DEPT, HSQC, HMBC and NOESY), mass spectrometry, and optical rotation data.
Changyih Duh - One of the best experts on this subject based on the ideXlab platform.
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new cytotoxic oxygenated fucosterols from the Brown Alga turbinaria conoides
Journal of Natural Products, 1999Co-Authors: Jyhhorng Sheu, Gueyhorng Wang, Pingjyu Sung, Changyih DuhAbstract:Fucosterol (1), 24ξ-hydroperoxy-24-vinylcholesterol (2), 29-hydroperoxystigmasta-5,24(28)-dien-3β-ol (3), 24-ethylcholesta-4,24(28)-dien-3-one (4), 24ξ-hydroperoxy-24-ethylcholesta-4,28(29)-dien-3-one (5), 24-ethylcholesta-4,24(28)-dien-3,6-dione (6), 24ξ-hydroperoxy-24-ethylcholesta-4,28(29)-dien-3,6-dione (7), 6β-hydroxy-24-ethylcholesta-4,24(28)-dien-3-one (8), and 24ξ-hydroperoxy-6β-hydroxy-24-ethylcholesta-4,28(29)-dien-3-one (9) were isolated from the marine Brown Alga Turbinaria conoides. The structures of these compounds were established by spectral analysis. Isolated for the first time from a natural source, the oxygenated fucosterols 4−9 exhibit cytotoxicity against various cancer cell lines.
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cytotoxic sterols from the formosan Brown Alga turbinaria ornata
Planta Medica, 1997Co-Authors: Jyhhorng Sheu, Gueyhorng Wang, Pingjyu Sung, Yenhung Chiu, Changyih DuhAbstract:: Two hydroperoxysterols 24-hydroperoxy-24-vinyl-cholesterol (1) and 29-hydroperoxystigmasta-5,24(28)-dien-3beta-ol (2), and fucosterol (3) were isolated from the Brown Alga Turbinaria ornata (Sargassaceae). Hydroperoxide 2 is a new natural compound and was converted into 29-hydroxystigmasta-5,24 (28)-dien-3beta-ol (4) by reaction with LAH. Sterols 1, 2, and 4 exhibited cytotoxicity against various cancer cell lines.
Louis Piovetti - One of the best experts on this subject based on the ideXlab platform.
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cystophloroketals a e unusual phloroglucinol meroterpenoid hybrids from the Brown Alga cystoseira tamariscifolia
Journal of Natural Products, 2015Co-Authors: Mohamed El Hattab, Annick Ortalomagne, Louis Piovetti, Naima Bouzidi, Gregory Gentajouve, Claire Hellio, Jeanphilippe Marechal, Olivier P Thomas, Gérald CulioliAbstract:Cystophloroketals A–E (1–5), five new phloroglucinol–meroditerpenoid hybrids, have been isolated together with their putative biosynthetic precursor, the monocyclic meroditerpenoid 6, from the Mediterranean Brown Alga Cystoseira tamariscifolia. They represent the first examples of meroditerpenoids linked to a phloroglucinol through a 2,7-dioxabicyclo[3.2.1]octane moiety. The chemical structures, including absolute configurations, were elucidated on the basis of extensive spectroscopic analysis (HR-ESIMS, 1D and 2D NMR, and ECD) and TDDFT ECD calculations. Compounds 1–6 were tested for their antifouling activity against several marine colonizing species (bacteria, fungi, invertebrates, micro- and macroAlgae). Compound 6 showed high potency for the inhibition of macrofoulers (invertebrates and macroAlgae), while cystophloroketals B (2) and D (4) displayed strong inhibition of the germination of the two macroAlgae tested and moderate antimicrobial activities (bacteria, microAlgae, and fungi).
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Cystophloroketals A–E, Unusual Phloroglucinol–Meroterpenoid Hybrids from the Brown Alga Cystoseira tamariscifolia
2015Co-Authors: Mohamed El Hattab, Louis Piovetti, Claire Hellio, Olivier P Thomas, Grégory Genta-jouve, Naïma Bouzidi, Annick Ortalo-magné, Jean-philippe Maréchal, Gérald CulioliAbstract:Cystophloroketals A–E (1–5), five new phloroglucinol–meroditerpenoid hybrids, have been isolated together with their putative biosynthetic precursor, the monocyclic meroditerpenoid 6, from the Mediterranean Brown Alga Cystoseira tamariscifolia. They represent the first examples of meroditerpenoids linked to a phloroglucinol through a 2,7-dioxabicyclo[3.2.1]octane moiety. The chemical structures, including absolute configurations, were elucidated on the basis of extensive spectroscopic analysis (HR-ESIMS, 1D and 2D NMR, and ECD) and TDDFT ECD calculations. Compounds 1–6 were tested for their antifouling activity against several marine colonizing species (bacteria, fungi, invertebrates, micro- and macroAlgae). Compound 6 showed high potency for the inhibition of macrofoulers (invertebrates and macroAlgae), while cystophloroketals B (2) and D (4) displayed strong inhibition of the germination of the two macroAlgae tested and moderate antimicrobial activities (bacteria, microAlgae, and fungi)
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dictyotadimer a a new dissymmetric bis diterpene from a Brown Alga of the genus dictyota
Tetrahedron Letters, 2011Co-Authors: Yannick Viano, Dominique Bonhomme, Annick Ortalomagne, Yves Blache, O. Thomas, Louis Piovetti, Mohamed El Hattab, Gérald CulioliAbstract:A phytochemical investigation of a Mediterranean Brown Alga (Dictyota sp.) led to the isolation of a novel C40 bis-diterpene, named dictyotadimer A. The chemical structure of this unusual dissymmetric dimer, characterized by a C–C linkage between two different xenicane units, was elucidated by 1D and 2D NMR analyses together with HR-ESI mass spectrometry. The relative configuration of the two diterpenoid components was determined by NOESY NMR correlations and molecular modeling. A plausible biogenetic pathway of dictyotadimer A was also proposed.
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Comparison of various extraction methods for identification and determination of volatile metabolites from the Brown Alga Dictyopteris membranacea.
Journal of chromatography. A, 2006Co-Authors: Mohamed El Hattab, Gérald Culioli, Louis Piovetti, Semch Eddine Chitour, Robert VallsAbstract:Three different methods: hydrodistillation (HD), focused microwave-assisted hydrodistillation (FMAHD) and supercritical fluid extraction (SFE) have been applied, for the first time together, for the extraction of volatile metabolites of the Brown Alga Dictyopteris membranacea. The oils obtained were analyzed by GC-MS (identification and determination of metabolites) and the results were compared. The main chemical classes of compounds identified were C11 hydrocarbons for HD method, sesquiterpenes for FMAHD method and sulphur compounds for SFE method.
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meroditerpenes from the Brown Alga cystoseira crinita off the french mediterranean coast
Phytochemistry, 1995Co-Authors: Annie Praud, Louis Piovetti, Robert Valls, Bernard Banaigs, Jeanyves BenaimAbstract:Abstract Three new meroditerpenes related to zosterdiol A have been isolated from the Brown Alga Cystoseira crinita . Their structures have been established mainly by means of 2D NMR experiments: COSY, HCCORR and HMBC correlations. They have also been quantitatively analysed and their geographical variation has been studied from a chemotaxonomic point of view.
Robert Valls - One of the best experts on this subject based on the ideXlab platform.
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Comparison of various extraction methods for identification and determination of volatile metabolites from the Brown Alga Dictyopteris membranacea.
Journal of chromatography. A, 2006Co-Authors: Mohamed El Hattab, Gérald Culioli, Louis Piovetti, Semch Eddine Chitour, Robert VallsAbstract:Three different methods: hydrodistillation (HD), focused microwave-assisted hydrodistillation (FMAHD) and supercritical fluid extraction (SFE) have been applied, for the first time together, for the extraction of volatile metabolites of the Brown Alga Dictyopteris membranacea. The oils obtained were analyzed by GC-MS (identification and determination of metabolites) and the results were compared. The main chemical classes of compounds identified were C11 hydrocarbons for HD method, sesquiterpenes for FMAHD method and sulphur compounds for SFE method.
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meroditerpenes from the Brown Alga cystoseira crinita off the french mediterranean coast
Phytochemistry, 1995Co-Authors: Annie Praud, Louis Piovetti, Robert Valls, Bernard Banaigs, Jeanyves BenaimAbstract:Abstract Three new meroditerpenes related to zosterdiol A have been isolated from the Brown Alga Cystoseira crinita . Their structures have been established mainly by means of 2D NMR experiments: COSY, HCCORR and HMBC correlations. They have also been quantitatively analysed and their geographical variation has been studied from a chemotaxonomic point of view.
Svetlana P Ermakova - One of the best experts on this subject based on the ideXlab platform.
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radiosensitizing effect of the fucoidan from Brown Alga fucus evanescens and its derivative in human cancer cells
Carbohydrate Polymers, 2019Co-Authors: Olesya S Malyarenko, E V Zdobnova, Artem S Silchenko, Mikhail I Kusaykin, Svetlana P ErmakovaAbstract:Fucoidan from Brown Alga Fucus evanescens and its product of enzymatic hydrolysis have precisely established structure and possess significant biological activities. The aim of present study was to determine radiosensitizing activity of fucoidan from Brown Alga F. evanescens and its derivative in human melanoma, breast adenocarcinoma, and colorectal carcinoma cell lines and elucidate mechanism of their action. The fucoidan from F. evanescens and its derivative had a comparable radiosensitizing activity and increased the inhibiting effect of X-ray radiation on proliferation and colony formation of human cancer cells, with significant inhibition of melanoma cells. The molecular mechanism of this action was associated with the induction of apoptosis by activating the initiator and effector caspases, suppressing the expression of the anti-apoptotic protein, and enhancing the fragmentation of DNA. The obtained data confirm the prospects of using fucoidan's derivative in combination with radiation therapy for the improvement of the schemes of cancer therapy.
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Ultrasound-assisted extraction of polysaccharides from Brown Alga Fucus evanescens. Structure and biological activity of the new fucoidan fractions.
Journal of Applied Phycology, 2017Co-Authors: Andrey B. Hmelkov, Natalia M. Shevchenko, Anton B. Rasin, Tatiana N. Zvyagintseva, Svetlana P ErmakovaAbstract:The application of an ultrasound-assisted extraction method, combined with ion-exchange chromatography, has allowed separation of the total fucoidan fraction (F1) from the Brown Alga Fucus evanescens into two fractions, F2 and F3, in the ratio 1:0.2. The traditionally extracted F1 differs from F3 only by the acetate groups at C3 being somewhat predominant. F2 is described as having acetate groups located chaotically, and contains galactose and xylose residues, in addition to fucose. F3 consists of fucose residues acetylated almost exclusively at C3. Therefore, with ultrasound-assisted extraction from the Brown Alga Fucus evanescens, a new regular 1 → 3;1 → 4-α-L-fucan was obtained. It is sulphated at C2 and acetylated at C3 of the fucose residue and showed anticancer activity in vitro towards human colon carcinoma cells comparable to the total fraction F1.
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fucoidans from Brown Alga fucus evanescens structure and biological activity
Frontiers in Marine Science, 2016Co-Authors: Roza V Menshova, Natalia M. Shevchenko, Tatiana N. Zvyagintseva, N N Besednova, Olesya S Malyarenko, Tatiana I Imbs, Tatyana S Zaporoshets, Svetlana P ErmakovaAbstract:Brown Alga Fucus evanescens, widespread in the Far Eastern seas of Russia, is valuable source of sulfated polysaccharides – fucoidans with beneficial biological activities. The most homogenous fraction of fucoidan from F. evanescens was shown to be molecule containing linear main chain of alternating 2-sulfated 1,3- and 1,4-linked α-L-fucose residues. Few sulfate groups were found in position 4 of some 1,3-linked fucose residues. Acetyl groups occupied free C-3 of 1,4-linked residues and/or the C-4 of 1,3-linked fucose residues. Enzymatic hydrolysis, mild acid hydrolysis and autohydrolysis of native fucoidan were used for elucidation of the fine structural characteristics of fucoidan from F. evanescens. The aim of this review to summarize published data on biological activities of fucoidan from F. evanescens: antiviral, anticoagulant, thrombolytic, hepatoprotective, immunomodulatory, anticancer, and their practical application.
