Isolation, Chiral-Phase Resolution, and Determination of the Absolute Configurations of a Complete Series of Stereoisomers of a Rearranged Acetophenone with Three Stereocenters.
A synthesis-inspired chemical investigation of the leaves of Melicope ptelefolia led to the isolation of evodialones A–D (1–4), four rearranged acetophenone stereoisomers possessing a prenylated acylcyclopentenone skeleton with three stereogenic carbons. Evodialones C and D (3 and 4) are new minor constituents. The chiral-phase HPLC resolution gave (+)-1–4 and (−)-1–4, eight enantiomers forming a complete stereoisomer library. Their absolute configurations were elucidated via extensive spectroscopic data and a modified Mosher’s method. The relationship between the chiral structures and their NMR and ECD data is discussed. Compounds (±)-1, -2, and -4 have significant protective effects on high-glucose-induced oxidative stress in human vein endothelial cells.
#1Ya-Qi Tang(SYSU: Sun Yat-sen University)H-Index: 4
#2Yi-Qiu Li(SYSU: Sun Yat-sen University)H-Index: 1
Last. Sheng Yin(SYSU: Sun Yat-sen University)H-Index: 17
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Two polyprenylated acylcyclopentanone racemates, evodialones A (1) and B (2), featuring a 3-ethyl-1,1-diisopentyl-4-methylcyclopentane skeleton, were isolated from an extract of the aerial parts of Evodia lepta. Evodialone A (1) was resolved by chiral-phase HPLC to afford a pair of enantiomers, (+)- and (−)-evodialones A (1b/1a), while evodialone B (2) could not be resolved. Their structures were elucidated by spectroscopic analysis and a combination of computational techniques including gauge-i...
#1Hui-Jun Zhao(CPU: China Pharmaceutical University)H-Index: 7
#2Ting Ma(CPU: China Pharmaceutical University)H-Index: 10
Last. Ling-Yi Kong(CPU: China Pharmaceutical University)H-Index: 58
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ABSTRACTOxidative stress plays a critical role in the pathogenesis of diabetic vascular complications. Trans-δ-viniferin (TVN), a polyphenolic compound, has recently attracted much attention as an antioxidant exhibiting a hypoglycemic potential. In the present study, we aimed at investigating the protective effect of TVN against high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and the potential mechanism involved. We found that TVN attenuated reactive oxyg...
Melicolones A (1) and B (2), a pair of rearranged prenylated acetophenone epimers with an unusual 9-oxatricyclo[3.2.1.13,8]nonane core, were isolated from the leaves of Melicope ptelefolia. Further chiral high-performance liquid chromatography resolution gave enantiomers (+)- and (−)-1, as well as (+)- and (−)-2, respectively. The structures and absolute configurations of the pure enantiomers were determined by extensive spectroscopic data and single crystal X-ray diffraction. All the isolated e...
The isolation and structure elucidation of a new meroterpenoid, actinoranone (1), produced by a marine bacterium closely related to the genus Streptomyces is reported. Actinoranone is composed of an unprecedented dihydronaphthalenone polyketide linked to a bicyclic diterpenoid. The stereochemistry of 1 was defined by application of the advanced Mosher’s method and by interpretation of spectroscopic data. Actinoranone (1) is significantly cytotoxic to HCT-116 human colon cancer cells with an LD50...
Last. Jae Youl Cho(SKKU: Sungkyunkwan University)H-Index: 65
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Abstract Ethnopharmacological relevance Evodia lepta (Spreng.) Merr., in the Rutaceae family, is a medicinal plant traditionally used to treat inflammatory symptoms such as in meningitis and hepatitis. However, no study has systematically investigated its anti-inflammatory activities including its molecular mechanism. Materials and methods The effects of a methanol extract from the roots Evodia lepta (El-ME) were evaluated using lipopolysaccharide (LPS)-treated RAW264.7 cells producing nitric ox...
α-Acids and β-acids, two main components of hop resin, are known to be susceptible to oxygen and degraded during hop storage, although the oxidation products in stored hops have not been fully identified. In this study, we developed a high-performance liquid chromatography (HPLC) analysis method suitable for separation and quantification of the oxidation products. This HPLC analysis clearly proved, for the first time, that humulinones and hulupones are major products in oxidized hops. We are als...
Last. Werner Kaminsky(UW: University of Washington)H-Index: 51
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The science and art of making beer, likely the oldest liquid fermented by humans, stretches over millennia. Production typically involves boiling beer wort together with hops, which acts as a natural preservative,1 but the generated iso-α-acids are known to be prone to decomposition,2, 3 and consequently, more stable reduced hops extracts, such as the tetrahydro-iso-α-acids, have been developed. These latter compounds are separately produced and frequently added to beer to achieve a consistent l...
In nature, chiral natural products are usually produced in optically pure form—however, occasionally both enantiomers are formed. These enantiomeric natural products can arise from a single species or from different genera and/or species. Extensive research has been carried out over the years in an attempt to understand the biogenesis of naturally occurring enantiomers; however, many fascinating puzzles and stereochemical anomalies still remain.
#1Sung-Jun Park(NIH: National Institutes of Health)H-Index: 4
#2Faiyaz Ahmad(NIH: National Institutes of Health)H-Index: 35
Last. Jay H. Chung(NIH: National Institutes of Health)H-Index: 25
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Resveratrol, a polyphenol in red wine, has been reported as a calorie restriction mimetic with potential antiaging and antidiabetogenic properties. It is widely consumed as a nutritional supplement, but its mechanism of action remains a mystery. Here, we report that the metabolic effects of resveratrol result from competitive inhibition of cAMP-degrading phosphodiesterases, leading to elevated cAMP levels. The resulting activation of Epac1, a cAMP effector protein, increases intracellular Ca2+ l...
Bioassay-guided fractionation of the culture extract of Aspergillus wentii EN-48, an endophytic fungus isolated from an unidentified marine brown algal species of the genus Sargassum, led to the isolation of three new tetranorlabdane diterpenoids, asperolides A-C (1-3), and five related derivatives (4-8). The structures of these compounds were established on the basis of spectroscopic interpretation, and compound 1 was confirmed by X-ray crystallographic analysis. The absolute configuration of I...
The dichloromethane extract from leaves of Melicope barbigera (Rutaceae), endemic to the Hawaiian island of Kaua’i, yielded four new and three previously known acetophenones and 2H-chromenes, all found for the first time in M. barbigera. The structures of the new compounds obtained from the dichloromethane extract after purification by chromatographic methods were unambiguously elucidated by spectroscopic analyses including 1D/2D NMR spectroscopy and HRESIMS. The absolute configuration was deter...
#1Min Zhao(CAS: Chinese Academy of Sciences)H-Index: 4
#2Da-Le Guo(CDUTCM: Chengdu University of Traditional Chinese Medicine)H-Index: 10
Last. Yan Zhou(CAS: Chinese Academy of Sciences)H-Index: 27
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Phytopathogenic fungi have been considered as being an enormous threat in the agricultural system. In our search of new antifungal natural products, nine new halogenated cyclopentenones, bicolorins A–I (1–3, and 5–10), along with three known cyclopentenones (4, 11, and 12) were isolated from the endophytic fungus Saccharicola bicolor of Bergenia purpurascens by the one strain-many compounds strategy. Their structures and absolute configurations were elucidated based on extensive spectroscopic an...
#1Jin-Fang Xu(Shanxi Medical University)H-Index: 6
#2Chao Han(CPU: China Pharmaceutical University)H-Index: 11
Last. Ling-Yi Kong(CPU: China Pharmaceutical University)H-Index: 58
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Abstract Melicolones C–K (1–9), nine acetophenone derivatives with three unprecedented architectures, were characterized from the leaves of Melicope ptelefolia. Among them, melicolone C (1) was a novel acetophenone analogue possessing a highly rearranged spiro skeleton. Melicolones D-F (2–4) were three novel acetophenone congeners bearing unusual octalactone ring. Melicolones G-K (5–9) were five new prenylated acetophenone derivatives featuring a 9-oxatricyclo [3.2.1.13, 8]nonane core. Their str...
Abstract Two new prenylated acetophenone derivatives racemates, meliviticines A ( 1 ) and B ( 2 ) with unprecedented rearranged skeletons, were isolated from Melicope viticina . Subsequent chiral resolution led to the separation of two pairs of enantiomers, (±)-meliviticines A ( 1a / 1b ) and (±)-meliviticines B ( 2a / 2b ). Their structures including absolute configurations were elucidated by extensive spectroscopic data, electronic circular dichroism analysis, and X-ray crystallography. A plau...
