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排序方式: 共有449条查询结果,搜索用时 31 毫秒
41.
Reddy MK Alexander-Lindo RL Nair MG 《Journal of agricultural and food chemistry》2005,53(23):9268-9273
The most abundant water soluble natural food colors are betacyanins and anthocyanins. Similarly, lycopene, bixin, beta-carotene, and chlorophyll are water insoluble colors. Pure betanin, bixin, lycopene, chlorophyll, beta-carotene, and cyanidin-3-O-glucoside were isolated from Beta vulgaris, Bixa orellana,Lycopersicum esculentum, Spinacia oleracea, Daucus carrota, and Prunus cerasus, respectively. These natural pigments, alone and in combination, were evaluated for their relative potencies against cyclooxygenase enzymes and tumor cell growth inhibition by using MCF-7 (breast), HCT-116 (colon), AGS (stomach), CNS (central nervous system), and NCI-H460 (lung) tumor cell lines. Among the colors tested, betanin, cyanidin-3-O-glucoside, lycopene, and beta-carotene inhibited lipid peroxidation. However, all pigments tested gave COX-1 and COX-2 inhibition and showed a dose-dependent growth inhibition against breast, colon, stomach, central nervous system, and lung tumor cells, respectively. The mixtures of these pigments were also evaluated for their synergistic effects and chemical interactions at various concentrations. The mixture of anthocyanin and betanin negated their efficacy in the cell growth inhibitory assay and did not enhance the COX enzyme inhibitory activity. This is the first report of a comparative evaluation and the impact on biological activities of these pigments alone and in combination. 相似文献
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43.
Characterization, quantification, and bioactivities of anthocyanins in Cornus species 总被引:3,自引:0,他引:3
Seeram NP Schutzki R Chandra A Nair MG 《Journal of agricultural and food chemistry》2002,50(9):2519-2523
Cornus mas, Cornus officinalis, Cornus controversa, and Cornus kousa (Cornaceae) bear edible fruits that are consumed in parts of Europe and Asia. This study undertook the investigation of the presence and levels of anthocyanins in the fruits of these Cornus species by HPLC. The anthocyanins present in Cornelian cherries, C. mas, are delphinidin 3-O-beta-galactopyranoside (1), cyanidin 3-O-beta-galactopyranoside (2), and pelargonidin 3-O-beta-galactopyranoside (3). C. officinalis contains only anthocyanins 1-3, similar to C. mas, but in different proportions. However, C. controversa contains anthocyanins 1-3 among other anthocyanins, but Chinese dogwood, C. kousa, did not contain 1-3. The contents of pure anthocyanins 1, 2, and 3 in 1 kg of fresh fruits of C. mas, C. officinalis, and C. controversa were 280, 1079, and 710 ppm; 11, 77, and 230 ppm; and 600, 1000, and 700 ppm, respectively. In cyclooxygenase (COX)-I and -II enzyme inhibitory assays, anthocyanins 1-3 (all 40 microM) showed activities of 9.2 and 11.7%; 7.6 and 12.4%; and 5.3 and 7.8%, respectively, compared to Naproxen (54.3 and 41.3%; 10 microM), ibuprofen (47.5 and 39.8%; 10 microM), Celebrex (46.2 and 66.3%; 1.67 ppm), and Vioxx (23.8 and 88.1%, 1.67 ppm). In the antioxidant assay, anthocyanins 1-3 (all 40 microM) showed activities of 70.2, 60.1, and 40.3%, respectively. At 10 microM concentration, commercial synthetic antioxidants tert-butylhydroquinone, butylated hydroxytoluene, butylated hydroxyanisole, and vitamin E gave 83.2, 79.7, 82.1, and 10.2% of antioxidant activity, respectively. 相似文献
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45.
An efficient method for the purification and characterization of nematicidal azadirachtins A,B, and H,using MPLC and ESIMS 总被引:2,自引:0,他引:2
Sharma V Walia S Kumar J Nair MG Parmar BS 《Journal of agricultural and food chemistry》2003,51(14):3966-3972
Azadirachtin A enriched concentrate containing 60% active ingredient (a.i.) was prepared from the methanolic extract of the de-fatted neem (Azadirachta indica A. Juss) seed kernels. Azadirachtins A, B, and H, the three major bioactive constituents of neem seed kernel, were purified from this methanolic concentrate by employing reverse phase medium-pressure liquid chromatography (MPLC), using methanol-water solvent system as an eluant. The three pure azadirachtin congeners thus obtained were characterized by their unique mass spectral fragmentation, using electrospray probe in positive ion mode (ESI). All three azadirachtins exhibited nematicidal and antifungal activities. Azadirachtin B was the most effective against the reniform nematode Rotylenchulus reniformis (EC(50) 96.6 ppm), followed by Azadirachtin A (119.1 ppm) and H (141.2 ppm). At 200-ppm concentration, the test compounds caused 50-65% mortality of Caenorhabditis elegans nematode. Azadirachtin H showed the highest activity against the phytophagous fungi Rhizoctonia solani (EC(50) 63.7 ppm) and Sclerotium rolfsii (EC(50) 43.9 ppm), followed by B and A. The isolation of pure azadirachtins A, B, and H directly by MPLC purification from its concentrate and their characterization by ESIMS are unique and less time-consuming. 相似文献
46.
Vitamin E. Regulation of the biosynthesis of porphyrins and heme 总被引:1,自引:0,他引:1
P P Nair H S Murty P I Caasi S K Brooks J Quartner 《Journal of agricultural and food chemistry》1972,20(3):476-480
47.
48.
Evolution of Marek's disease -- a paradigm for incessant race between the pathogen and the host 总被引:8,自引:0,他引:8
Nair V 《Veterinary journal (London, England : 1997)》2005,170(2):175-183
Marek's disease (MD) is a highly contagious lymphoproliferative disease of poultry caused by the oncogenic herpesvirus designated Marek's disease virus (MDV). MD has a worldwide distribution and is thought to cause an annual loss over 1 bn US dollars to the poultry industry. Originally described as a paralytic disease, today MD is mostly manifested as an acute disease with tumours in multiple visceral organs. MD is controlled essentially by the widespread use of live vaccines administered either in ovo into 18-day-old embryos or into chicks immediately after they hatch. In spite of the success of the vaccines in reducing the losses from the disease in the last 30 years, MDV strains have shown continuous evolution in virulence acquiring the ability to overcome the immune responses induced by the vaccines. During this period, different generations of MD vaccines have been introduced to protect birds from the increasingly virulent MDV strains. However, the virus has countered each new vaccine with ever more virulent strains. This continuous race between the virus and the host is making the control of this poultry health problem a major challenge for the future. 相似文献
49.
50.
Li B Yu JP Brunzelle JS Moll GN van der Donk WA Nair SK 《Science (New York, N.Y.)》2006,311(5766):1464-1467
Nisin is a posttranslationally modified antimicrobial peptide that is widely used as a food preservative. It contains five cyclic thioethers of varying sizes that are installed by a single enzyme, NisC. Reported here are the in vitro reconstitution of the cyclization process and the x-ray crystal structure of the NisC enzyme. The structure reveals similarities in fold and substrate activation with mammalian farnesyl transferases, suggesting that human homologs of NisC posttranslationally modify a cysteine of a protein substrate. 相似文献