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1.
Eight methoxyflavones were isolated and identified from the peel of calamondin. Citromitin and 5-O-desmethylcitromitin are actually nobiletin and 5-O-desmethylnobiletin, respectively. 5,6,7,8,3′,4′-Hexamethoxyflavanone and 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavanone are not constituents of calamondin, although previously reported. 相似文献
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The effect of alcohols on the spectral properties of riboflavin derivatives in non-polar solvent was studied by various spectroscopic methods in order to support the view point that alcohol may directly interact with the isoalloxazine moiety of FAD and enhance the catalytic activity of D-amino acid oxidase (DAAO). The most likely association complex between alcohol and riboflavin is 1 : 1 stoichiometric complex through the 3-N imino and the 2-C carbonyl groups of the isoalloxazine ring and the hydroxyl group of alcohols. It appears that methanol has a larger association constant than any other alcohols, and the association constant decreases with the increase in carbon number and with the steric requirement of the alkyl group of alcohols. 相似文献
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The role of metabolic activation in the binding of polychlorinated biphenyls (PCBs) to cellular macromolecules was investigated in vivo by comparing the relative binding of 2,4,5,2′,4′,5′-[U-14C]hexachlorobiphenyl (2,4,5), a slowly metabolized PCB, with that of 2,3,6,2′,3′,6′-[U-14C]hexachlorobiphenyl (2,3,6), a rapidly metabolized PCB, and the appropriate controls. Each hexachlorobiphenyl was administered to mice, orally for 5 days (7.28 mg/kg/day). Following the dosing schedule, animals were killed at 1, 5 and 8 days. The concentration of each PCB was determined in liver, muscle and kidney and in purified macromolecules isolated from those tissues. The concentration of 2,4,5 was consistently higher than the concentration of 2,3,6 in all tissues studied. However, the amount of 2,3,6 bound to the purified macromolecules was consistently at least one order of magnitude greater than that of 2,4,5. The greatest binding was observed in RNA followed by protein and DNA, respectively. The purity of the macromolecules and the presence of PCB-derived radioactivity at the monomer level were confirmed. This is the first report of 14C-labeled PCB being bound to purified RNA, DNA, and proteins isolated from the tissues of animals treated in vivo. The binding is thought to be covalent and to be the result of metabolic activation. 相似文献
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George Britton Harish C. Malhotra Raj Kumari Singh Sandra Taylor Trevor W. Goodwin Avraham Ben-Aziz 《Phytochemistry》1976,15(12):1971-1972
Two new carotenoids isolated from Rhodopseudomonas spheroides (Rhodospirillaceae) have been identified as methoxyspheroidene (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,78′-hexahydro-ψ,ψ-carotene) obtained from anaerobic cultures and methoxyspheroidenone (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7′,8′-hexahydro-ψ,ψ-caroten-2-one) recovered from aerobic cultures. 相似文献
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Two dihydrochalcones, 2′,6′-dihydroxy-4′-methoxydihydrochalcone and 2,4′,6′-trihydroxydihydrochalcone have been isolated from leaves of Lindera umbellata. 相似文献
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Leovigildo Quijano José S. Calderón Federico Gómez G Edgar Escobar Tirso Rios 《Phytochemistry》1985,24(5):1085-1088
Two new highly oxygenated flavones, were isolated from aerial parts of Ageratum houstonianum. Their structures were established as 3′-hydroxy-5,6,7,8,2′,4′,5′-heptamethoxyflavone and 5,3′-dihydroxy-6,7,8,2′,4′,5′-hexamethoxyflavone on the basis of spectral data and chemical degradation. The structure of the latter compound was confirmed by X-ray analysis. 相似文献
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A new flavone isolated from Isoetes has been identified as 2′,4′,5,5′,7-pentahydroxy flavone. 相似文献
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The natural occurrence of 7′,8′,11′,12′-tetrahydro-γ-carotene (7′,8′,11′,12′-tetrahydro-γ-carotene, IV) is predicted and its isolation from diphenylamine-inhibited cultures of a mutant of Phycomyces blakesleeanus and characterization are described. The possible role of this novel monocyclic carotene in β-carotene biosynthesis is discussed. 相似文献
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Polychlorinated biphenyl isomers and congeners as inducers of both 3-methylcholanthrene- and phenobarbitone-type microsomal enzyme activity 总被引:1,自引:0,他引:1
Highly purified synthetic polychlorinated biphenyls substituted in the meta and para positions of both phenyl rings and at one ortho position were administered to male Wistar rats and the effects of these compounds on the microsomal drug-metabolising enzymes were evaluated. The in vivo effects of these compounds were determined by measuring the microsomal benzo[a]pyrene hydroxylase, dimethylaminoantipyrine N-demethylase and NADPH-cytochrome c reductase enzyme activities, the cytochrome b5 content and the relative peak intensities and spectral shifts of the reduced microsomal cytochrome P-450 : CO and ethylisocyanide binding difference spectra. The results were compared to the effects of administering phenobarbitone (PB), 3-methylcholanthrene (MC), 2,2',4,4'-tetrachlorobiphenyl (TCBP-II) (a PB-type inducer), 3,3',4,4'-tetrachlorobiphenyl (TCBP-I) (an MC-type inducer), PB plus MC (coadministered) and TCBP-II + TCBP-I (coadministered) to the test animals. At dosage levels of 30 and 150 mumol . kg-1, pretreatment with 2,3,3',4,4'-pentachlorobiphenyl (PCBP-II), 2,3',4,4',5-pentachlorobiphenyl (PCBP-I), 2,3,3',4,4',5-hexachlorobiphenyl (HCBP-II) and 2,3,3',4,4',5-hexachlorobiphenyl (HCBP-III) gave hepatic microsomes with enzymic and spectral properties consistent with a mixed pattern of induction. These polychlorinated biphenyl (PCB) isomers and congeners have been identified as either major or minor components of the commercial PCB mixtures and must contribute to their activity as MC-type inducers. The only PCB isomer in this series which was not a mixed type inducer was 2,3',4,4',5,5'-hexachlorobiphenyl (HCBP-I) which appeared to be a PB-type inducer. This contrasted to the mixed-type activity observed for 2,3',4,4',5,5'-hexabromobiphenyl which was isolated from a commercial polybrominated biphenyl (PBB) mixture. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(4):858-861
The distribution of sarcophytol-A in the Sarcophyton genus was investigated in seven samples belonging to S. glaucum (3 samples), S. infundibulifurme (2 samples), S. crassocaule (1 sample) and S. trocheliophorum (1 sample) that were collected on Ishigaki Island in Okinawa Prefecture. Sarcophytol-A was present in one sample each of S. glaucum and S. infundibulifurme. This study indicates that the composition of cembranoids in the Sarcophyton genus is not related with the respective species, but with the individual samples collected. 相似文献
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A.A.leslie Gunatilaka Sarath R. Sirimanne Subramaniam Sotheeswaran H.T.Badra Sriyani 《Phytochemistry》1982,21(3):805-806
From the bud exudates of Gardenia cramerii and G. fosbergii, two species endemic to Sri Lanka, a new flavonoid with an unusual B-ring oxidation pattern, 5,5′-dihydroxy-6,7,2′,3′-tetramethoxyflavone, was characterized. Two other rare flavonoids, 5,3′,5′-trihydroxy-3,6,7,4′-tetramethoxyflavone and 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavone were also isolated from both Gardenia species. 相似文献
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F F Kadlubar K C Morton D M Ziegler 《Biochemical and biophysical research communications》1973,54(4):1255-1261
Organic hydroperoxides are capable of supporting the C-oxidation of several different amines in the presence of hepatic microsomes. Evidence is presented that indicates that microsomal cytochrome P-450 acts as the catalyst. Removal of the NADPH-cytochrome oxidoreductase or essential phospholipid from microsomes does not significantly affect the peroxidase activity. Of the amine substrates C-oxidized by organic hydroperoxides in the presence of microsomes, only aminopyrine and dimethylaniline are rapidly oxidized by hydroperoxides in the presence of catalase. The catalase-mediated reaction can also be distinguished from the microsomal-catalyzed reaction by the use of differential inhibitors. 相似文献
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3,5,6,7,8,2′,4′,5′-Octamethoxyflavone has been isolated from the whole plant of Pogostemon purpurascens. 相似文献
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C-Glycosylation of 5,7-dihydroxy-3′,4′,5′-trimethoxyflavone was carried out with acetobromo-α-d-glucose, -α-d-galactose, -α-d-xylose, -β-l-arabinose and -αt-L-rhamnose. The respective 6-C-glycosides and 6, 8-di-C-glycosides (excepted for galactose) were isolated and permethylated. MS and TLC comparison confirmed the proposed structures of five natural tricetin-derived C-glycosides. 相似文献