New Prenylated Bi- and Tricyclic Phloroglucinol Derivatives from Hypericum papuanum

Winkelmann, Karin; Heilmann, Jörg; Zerbe, Oliver; Rali, Topul; Sticher, Otto

doi:10.1021/np0006364

Cited by 54 publications

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“…Leach et al [2] reported about the antibacterial activity of a Soxhlet acetone extract of the leaves of H. papuanum (Guttiferae) against the Gram-positive bacterium S. aureus. In our continuing search for biologically active metabolites derived from plants that are employed in the traditional medicine of Papua New Guinea, we have previously isolated 13 acylphloroglucinol derivatives (ialibinones A ± E, papuaforins A ± E, hyperguinones A and B, and hyperpapuanone) from the petroleum-ether extract of this plant [3] [4]. Some of them displayed antibacterial (Bacillus cereus, Staphylococcus epidermidis, and Micrococcus luteus) and cytotoxic activity (KB cells).…”

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“…C(1) 65.6 (s b )) 65.6 (s b )) 65.6 (s b )) C (2) 192.8 (s b )) 193.3 (s b )) 193.3 (s b )) C (3) 111.2 (s) 107.4 (s) 107.7, 107.9 (2s b )) C (4) 200.3 (s) 201.7 (s b )) 201.7 (s b )) C (5) 62.5 (s b )) 62.7 (s) 62.9 (s b )) HÀC (6) 53 . system determines the relative configuration at the chirality centres C(1) and C (5). The carbonyl bridge between C(1) and C(5) constrains the substituents at C(1) and C (5) to be cis and, hence, MeÀC (5) is positioned below the plane of the five-membered ring.…”

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“…The 1'-hydroxyialibinones 4/4a, 5/5a, and 6/6a, and the other tested compounds show identical or slightly reduced antibacterial activity compared with the ialibinones [3]. The cytotoxic activity is rather weak, compared with other phloroglucinol derivatives previously isolated from H. papuanum [4]. The ialibinones A, B, and D displayed IC 50 values of 8.0 AE 2.1, 7.3 AE 1.9, and 6.6 AE 1.9 mg/ml, respectively, compared to 25.3 AE 1.4, > 40, and 32.5 AE 3.2 mg/ml of the corresponding 1'-hydroxyialibinones 4/4a, 5/5a, and 6/6a, respectively.…”

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Further Prenylated Bi- and Tricyclic Phloroglucinol Derivatives fromHypericum papuanum

Winkelmann

Heilmann

Zerbe

et al. 2001

HCA

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From the petroleum-ether extract of the dried aerial parts of Hypericum papuanum, three new prenylated tricyclic and four new bicyclic acylphloroglucinol derivatives were isolated by bioactivity-guided fractionation. The structures of the bicyclic compounds enaimeone A, B, and C (1/1a, 2/2a, and 3/3a, resp.) were elucidated as rel-(1R(3/3a). The tricyclic isolates 8-hydroxy-3b-(1-hydroxy-1-methylethyl)-4,4,7-trimethyl-9-(2-methylpropanoyl)-5bH-tricyclo[5.3.1.0 1,5 ]undec-8-ene-10,11-dione (4), 8-hydroxy-3a-(1-hydroxy-1-methylethyl)-4,4,7-trimethyl-9-(2-methylpropanoyl)-5bH-tricyclo[5.3.1.0 1,5 ]undec-8-ene-10,11-dione (5), and 8-hydroxy3a-(1-hydroxy-1-methylethyl)-4,4,7-trimethyl-9-(2-methylbutanoyl)-5bH-tricyclo[5.3.1.0 1,5 ]undec-8-ene-10,11-dione (6), and their corresponding tautomers 4a, 5a, and 6a, were named 1'-hydroxyialibinones A, B, and D, respectively. Oxidative decomposition of furonewguinone A ( 2,3,3a,5-tetrahydro-3a-hydroxy-2-(1-hydroxy-1-methylethyl)-5-methyl-5-(3-methylbut-2-enyl)-7-(2-methylpropanoyl)-benzofuran-4,6-dione; 7) led to furonewguinone B ( 3,3a,7,7a-tetrahydro-3a,6,7a-trihydroxy-2-(1-hydroxy-1-methylethyl)-7-methyl-7-(3-methylbut-2-enyl)-5-(2-methylpropanoyl)benzofuran-4(2H)-one; 8/8a). Structure elucidation was based on extensive 1D and 2D NMR studies, as well as on data derived from mass spectrometry. Furthermore, the cytotoxicity towards KB nasopharyngeal carcinoma cells and the antibacterial activity were determined.

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Further Prenylated Bi- and Tricyclic Phloroglucinol Derivatives fromHypericum papuanum

Winkelmann

Heilmann

Zerbe

et al. 2001

HCA

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“…838 high antibacterial activity. [6][7][8][9] The Hypericum brasiliense presents three phloroglucinols in its constitution and they are active against bacteria.…”

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“…4,5 Phloroglucinol derivatives have been described in the literature as promising substances with high antibacterial activity. [6][7][8][9] The Hypericum brasiliense presents three phloroglucinols in its constitution and they are active against bacteria. 10,11 These phloroglucinols are the japonicin A, the uliginosin B and the isouliginosin B ( Figure 1).…”

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Conformational analysis of phloroglucinols from hypericum Brasiliense by using x-ray diffraction and molecular modeling

Leal

Yoneda

Lindgren

et al. 2010

J. Braz. Chem. Soc.

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Neste trabalho, verificou-se a aplicabilidade de uma metodologia computacional para se predizer a estrutura de compostos orgânicos com atividade biológica. Para isso, selecionaramse três floroglucinóis, e compararam-se suas conformações obtidas por modelagem molecular e por difração de raios X. Os resultados mostraram que as conformações obtidas por análise conformacional com o método AM1 seguidas de otimização de geometria utilizando o método DFT (B3LYP/6-31G(d,p)) estão em boa concordância com os dados obtidos experimentalmente por difração de raios X, indicando que a metodologia empregada parece ser uma ótima ferramenta para predizer preferências conformacionais desta classe de compostos.In this work we intend to verify the applicability of a computational methodology to predict structural features of organic compounds with biological activity. We selected three phloroglucinols and compared their calculated conformational data with their X-ray crystallographic structure. The results showed that conformations obtained by conformational analysis with the AM1 method followed by geometry optimization by using the DFT B3LYP/6-31 G(d,p) basis set are in very good agreement with X-ray data, indicating that the methodology employed here seems to be a very useful tool in order to predict the conformational preference for this class of compounds.Keywords: conformational analysis, X-ray, molecular modeling, phloroglucinols IntroductionDespite the development of organic synthesis, biotechnology and combinatorial chemistry, natural plants are still a great source of bioactive compounds. However, just 8% of the Brazilian flora has been already studied in the search for new bioactive substances. 1,2 In the last decades several antibacterial compounds are being less effective in the treatment of infectious diseases due to multi-resistant bacteria.3 In this context medicinal plants are extremely important in the search of new molecules as therapeutic alternatives. The genus Hypericum seems to be a good choice for this problem. It is constituted by flavonoids, xantones and phloroglucinols with considerable pharmacological and biological effects.4,5 Phloroglucinol derivatives have been described in the literature as promising substances with Conformational Analysis of Phloroglucinols from Hypericum Brasiliense J. Braz. Chem. Soc. 838 high antibacterial activity. [6][7][8][9] The Hypericum brasiliense presents three phloroglucinols in its constitution and they are active against bacteria.10,11 These phloroglucinols are the japonicin A, the uliginosin B and the isouliginosin B (Figure 1).The study of conformations of bioactive compounds is very important in the design of new drugs, since that conformational profile may have direct implications in their activity. When the conformational properties of a drug are known to play an important role in establishing its therapeutic value, any newly designed analogue should have similar conformational properties to enhance the probability that it will bind to the receptor target.Nowada...

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Triethyamine‐promoted [5+3] Cycloadditions for Regio‐ and Diastereoselective Synthesis of Functionalized aza‐Bicyclo[3.3.1]alkenones

et al. 2022

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We have developed a synthetic strategy for Et 3 N-promoted [5 + 3] cycloaddition reactions between acetoxypyranones and azomethine imines to access functionalized azabicyclo[3.3.1]alkenones with three tertiary stereocenters (31 examples, 36% to 87% yield, 5.5:1 to > 20:1 dr). The method was scalable, and the products could be transformed to various eight-membered-ring bridged heterocyclic molecules.

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New Prenylated Bi- and Tricyclic Phloroglucinol Derivatives from Hypericum papuanum

Cited by 54 publications

References 13 publications

Further Prenylated Bi- and Tricyclic Phloroglucinol Derivatives fromHypericum papuanum

Further Prenylated Bi- and Tricyclic Phloroglucinol Derivatives fromHypericum papuanum

Conformational analysis of phloroglucinols from hypericum Brasiliense by using x-ray diffraction and molecular modeling

Triethyamine‐promoted [5+3] Cycloadditions for Regio‐ and Diastereoselective Synthesis of Functionalized aza‐Bicyclo[3.3.1]alkenones

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