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Zahid S Udenigwe CC Ata A Eze MO Segstro EP Holloway P 《Natural product research》2006,20(14):1283-1289
Chemical studies on the crude methanolic extract of Coprinus micaceus, collected from the Canadian Prairie region, have resulted in the isolation of two new natural products, micaceol (1), a sterol and (Z,Z)-4-oxo-2,5-hetpadienedioic acid (2). Compound 2 was isolated for the first time as a natural product. Structures of these new compounds were established with the aid of extensive NMR spectroscopic studies. Compound 1 has shown anti-bacterial activity against Corynebacterium xerosis and Staphylococcus aureus, whereas compound 2 exhibited glutathione S-transferase inhibition. 相似文献
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Seven secondary metabolites, p-hydroxybenzoic acid (1), 3,4-dihydroxybenzoic acid (2), ferulic acid (3), 2,6-dimethoxy-4-hydroxy acetophenone (4), lupeol (5), 2'-O-ethylmurrangatin (6) and hibiscetin heptamethyl ether (7) were the natural products isolated from various medicinal plants. Their structures were identified by spectral comparison with previously reported data. The compounds 1-7 were screened for their tyrosinase-inhibitory activity. The compound p-hydroxybenzoic acid (1) was found to have potent activity against tyrosinase enzyme, whereas lupeol (5) showed significant activity. 相似文献
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The combretastatins are a group of anti-mitotic agents isolated from the bark of the South African tree Combretum caffrum. The most potent member is combretastatin A-4, and this compound together with a phosphate pro-drug form have already progressed through into clinical trails for the treatment of solid tumours. What makes this class of compounds rather more interesting than other anti-mitotic agents is that they are also angiogenesis inhibitors, and are being evaluated for their efficacy in the treatment of diabetic retinopathy which is the biggest single cause of blindness They are thus of considerable contemporary interest. 相似文献
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Dvornikova I. A. Frolova L. L. Churakov A. V. Kuchin A. V. 《Russian Chemical Bulletin》2004,53(6):1323-1326
The reaction of enantiomerically pure (–)-2-hydroxypinan-3-one with ethylenediamine was studied. Depending on the reagent ratio, the reaction can afford either mono- or bis-Schiff"s bases. The enantiomerically pure unsymmetrical terpenoid salen-type ligand was prepared by the reaction of 3-[(2-aminoethyl)imino]pinan-2-ol with salicylaldehyde. 相似文献
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Nowadays, the mangrove biome is considered to be a profound resource of natural products usually possessing cytotoxicity of a broader range. Covering the period 2007–2015, a total of 21 new naturally occurring compounds has stood out. For example, xylogranin B and swietephragmin C were found to exhibit very potent cytotoxic activity against the colon HCT-116 cells reaching IC50 values of 0.05 and 0.06 μM, respectively. Bearing in mind the efficacy of the majority compounds in the preliminary in vitro screens, these studies should be expanded to both ex vivo and in vivo screens including the evaluation of the relevant toxicological profiles. 相似文献
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GONG YongYang TAN YeQiang MEI Ju ZHANG YiRen YUAN WangZhang ZHANG YongMing SUN JingZhi TANG Ben Zhong 《中国科学:化学(英文版)》2013,56(9):1178-1182
Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens. 相似文献
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Da Wang Bin Yu Chuming Chen Jie Duan Donghua Di Xin Xiong 《Natural product research》2018,32(9):997-1003
The Xanthoceras sorbifolia Bunge husks were known for their abundant triterpenoids resource, which contributed to many bioactivities, such as antitumor, antiinflammatory and neuroprotection. The present study has led to the purification of a new triterpenoid saponin, 21β-O-acetyl-xanthohuskiside A (1), together with six known barrigenol derivatives (2–7), whose structures were authenticated on the basis of NMR, HR-MS, IR spectrum and acid hydrolysis experiment. Compound 7 showed more noteworthy cytotoxicity towards three human tumour cell lines (HCT-116, HepG-2 and U87-MG) than other compounds. 相似文献
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Michael Kluge Holger Hartenstein Achim Hantschmann Dieter Sicker 《Journal of heterocyclic chemistry》1995,32(2):395-402
2,7-Dihydroxy-2H-1,4-benzoxazin-3(4H)-one 11 (DHBOA) and 2,4,7-trihydroxy-2H-1,4-benzoxazin-3(4H)-one 14 (TRIBOA) representing aglucones of naturally occurring acetal glucoside type allelo chemicals found in Gramineae have been for the first time synthesized by two pathways both involving selective reductive cyclizations of appropriate 7-benzyloxy-2-nitrophenol derivatives as precursors. TRIBOA 14 and its bioactive naturally occurring 7-methyl ether DIMBOA have been found to undergo a hitherto unknown transformation to the corresponding 2,6-dibromo substituted lactam forms 20 and 21 in the presence of hydrogen bromide in acetic acid, which is of value in a better understanding of the possible mode of bioactivity. 相似文献
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Carlos A. Escobar Michael Kluge Dieter Sicker 《Journal of heterocyclic chemistry》1997,34(5):1407-1414
4-Acetylbenzoxazolin-2(3H)-one has been prepared biomimetically during attempts to synthesize the hemiacetalic hydroxamic acid 5-acetyl-2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one by the immediate degradation of this unstable compound generated as an intermediate. Thus, 4-acetylbenzoxazolin-2(3H)-one recently isolated from Zea mays kernels, and similar to other benzoxazolin-2(3H)-ones known from plant sources, is assumed to have originated from the degradation of natural 5-acetyl-2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one which in turn could have been enzymatically released by a β-glucosidase from the corresponding 2-β-D-glucoside. 相似文献
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Reaction of pyranulose 6 with styrenes 12c or 13 and Et3N in CH2Cl2 at 25 °C afforded the [5+2] cycloadducts 14c and 15, which were hydrolyzed to give the natural products 1 and descurainin (2) in 24 and 27% overall yield, respectively. Heating pyranulose 6 with cinnamate ester 21 in the presence of 2,6-di-t-butylpyridine in CH3CN at 175 °C afforded the [5+2] cycloadduct, which was hydrolyzed to give cartorimine (3) in 13% yield. 相似文献
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Tanja Grkovic 《Tetrahedron》2009,65(32):6335-207
A survey of the secondary metabolite chemistry profiles of New Zealand sponges of the genus Latrunculia has yielded new members of the discorhabdin A- and B-type families. The structure elucidation of (+)-(6R,8S)-1-thiomethyldiscorhabdin G∗/I (5) and both enantiomers of 16a,17a-dehydrodiscorhabdin W (6) are reported. Absolute configurations were assigned by comparison with a dataset of recently reported electronic circular dichroism spectra of discorhabdin alkaloids. A stereochemical correction of the recently reported natural product (+)-3-dihydrodiscorhabdin A from (3S,5R,6S,8S)-(7) to the C3-epimeric (+)-(3R,5R,6S,8S)-(8) and assignment of absolute configuration is also presented. Semi-synthesis of (+)-(3S,5R,6S,8S)-(7) from (+)-discorhabdin A provided further evidence for this structure revision. Cytotoxicity data is reported for 5-8. 相似文献
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The first total synthesis of eutypoid A and a new synthesis of racemic microperfuranone and gymnoascolide A have been achieved. The key steps in our synthetic strategy involve a Suzuki coupling reaction to install the C3 aryl ring and a Mannich-type reaction for the construction of the 4-benzylbutenolide core. 相似文献
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Finefield JM Sherman DH Kreitman M Williams RM 《Angewandte Chemie (International ed. in English)》2012,51(20):4802-4836
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. 相似文献
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Chunling Ge Yu Hu Fan Zhang Yongqin Lv Tianwei Tan 《Journal of separation science》2014,37(22):3253-3259
A new type of agar chromatography media has been prepared with a yield over 80% using a water‐in‐oil emulsion technique. These microspheres have regular spherical shapes and particle diameters in the range 40–165 μm (average ~90 μm). Cross‐linking of the resulting agar microspheres with epichlorohydrin and 1,4‐butanediol diglycidyl ether enhanced their mechanical and thermal stability. The alkaline conditions used during the cross‐linking reaction also decreased the content of ionized sulfate groups of the polysaccharide, thus reducing the nonspecific adsorption of positively charged molecules. The cross‐linked agar microspheres were functionalized with (i) branched poly(ethyleneimine) to obtain a stationary phase useful for the separation of proteins in an anion‐exchange mode and (ii) with poly‐β‐cyclodextrin enabling direct isolation and purification of puerarin from a crude extract of Radix puerariae. Using a 23.5 mL column loaded with 20 mg extract (0.85 mg/mL gel), puerarin with a purity of 96% was recovered with a yield of 86%. 相似文献
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T. E. Glotova M. Yu. Dvorko V. G. Samoilov I. A. Ushakov 《Russian Journal of Organic Chemistry》2008,44(6):866-869
3-Bromo-1-phenylprop-2-yn-1-one reacted with 1-benzylidenethiocarbonohydrazones in acetic acid or acetonitrile at room temperature (reaction time 3 h) to give in good yields the corresponding benzaldehyde N′-(5-benzoylmethyl-1,3,4-thiadiazol-2-yl)hydrazone hydrobromides which were converted into the free bases by treatment with aqueous ammonia. 相似文献
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An overview of marine natural products synthesis during 2003 is provided. The emphasis on total syntheses of molecules of contemporary interest, new total syntheses, and syntheses that have resulted in structure conformation or stereochemical assignments. 相似文献
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An overview of marine natural products synthesis during 2006 is provided. As with earlier installments in this series, the emphasis is on total syntheses of molecules of contemporary interest, new total syntheses, and syntheses that have resulted in structure confirmation or stereochemical assignments. 相似文献