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1.
Antimicrobial activity of Memecylon malabaricum leaves 总被引:4,自引:0,他引:4
The petroleum ether, chloroform and methanol extracts of Memecylon malabaricum leaves were tested for antimicrobial activity. Only methanol extract has shown activity against bacteria both Gram (+) and Gram (-), and fungi. 相似文献
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Sathanandam Pavithra N. Patil Prakash Rekha Ajitha Muthuvel Iyamperumal Patel Amrutlal R. Boggala Ramesh B. Shirol Adiveppa M. Ravishankar Kundapura V. 《Genetic Resources and Crop Evolution》2022,69(8):2787-2801
Genetic Resources and Crop Evolution - Manilkara zapota (L.) P. Royen, a widely adapted and popular tree meant for its appetizing fruits in tropics with no genomic resources like microsatellite... 相似文献
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Chemical composition, iron bioavailability, and antioxidant activity of Kappaphycus alvarezzi (Doty)
Fayaz M Namitha KK Murthy KN Swamy MM Sarada R Khanam S Subbarao PV Ravishankar GA 《Journal of agricultural and food chemistry》2005,53(3):792-797
Kappaphycus alvarezzi, an edible seaweed from the west coast of India, was analyzed for its chemical composition. It was found that K. alvarezzi is rich in protein (16.24% w/w) and contains a high amount of fiber (29.40% w/w) and carbohydrates (27.4% w/w). K. alvarezzi showed vitamin A activity of 865 mug retinal equivalents/100 g of sample. It contained a higher quantity of unsaturated fatty acids (44.50% of the total), in which relative percentage of oleic acid was 11%, cis-heptadecanoic acid 13.50%, and linoleic acid 2.3% and 37.0% of saturated fatty acids (mainly heptadecanoic acid). K. alvarezziwas also found to be good source of minerals, viz 0.16% of calcium, 0.033% of iron, and 0.016% of zinc, which are essential for various vital biological activities. Bioavailability of iron by in vitro methods showed a higher efficiency in intestinal conditions than in stomach conditions. Ascorbic acid influenced higher bioavailability of iron. Successive extracts of n-hexane, acetone, ethyl acetate, ethanol, and direct extractables of chloroform/methanol (1:1 and 2:1) were screened for antioxidant activity using a beta-carotene linoleic acid model system (B-CLAMS), DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) model system and hydroxyl radical scavenging activity. The chloroform/methanol (2:1) extract has shown 82.5% scavenging activity at 1000 ppm. Acetone fraction extracts at the 1000 ppm level showed 63.31% antioxidant activity in beta-carotene linoleic acid system. The acetone extract showed 46.04% scavenging activity at 1000 ppm concentration. In the case of hydroxyl radical scavenging activity, all the extracts showed better activity at the concentrations of 25 and 50 ppm, where at the 50 ppm level ethyl acetate extract showed 76.0%, acetone 75.12%, and hexane 71.15% activity, respectively. Results of this study suggest the utility of K. alvarezzi (Eucheuma) for various nutritional products, including antioxidant for use as health food or nutraceutical supplement. 相似文献
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Rounds L Havens CM Feinstein Y Friedman M Ravishankar S 《Journal of agricultural and food chemistry》2012,60(14):3792-3799
Meats need to be heated to inactivate foodborne pathogens such as Escherichia coli O157:H7. High-temperature treatment used to prepare well-done meats increases the formation of carcinogenic heterocyclic amines (HCAs). We evaluated the ability of plant extracts, spices, and essential oils to simultaneously inactivate E. coli O157:H7 and suppress HCA formation in heated hamburger patties. Ground beef with added antimicrobials was inoculated with E. coli O157:H7 (10(7) CFU/g). Patties were cooked to reach 45 °C at the geometric center, flipped, and cooked for 5 min. Samples were then taken for microbiological and mass spectrometry analysis of HCAs. Some compounds were inhibitory only against E. coli or HCA formation, while some others inhibited both. Addition of 5% olive or apple skin extracts reduced E. coli O157:H7 populations to below the detection limit and by 1.6 log CFU/g, respectively. Similarly, 1% lemongrass oil reduced E. coli O157:H7 to below detection limits, while clove bud oil reduced the pathogen by 1.6 log CFU/g. The major heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were concurrently reduced with the addition of olive extract by 79.5% and 84.3% and with apple extract by 76.1% and 82.1%, respectively. Similar results were observed with clove bud oil: MeIQx and PhIP were reduced by 35% and 52.1%, respectively. Addition of onion powder decreased formation of PhIP by 94.3%. These results suggest that edible natural plant compounds have the potential to prevent foodborne infections as well as carcinogenesis in humans consuming heat-processed meat products. 相似文献
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Sanjaya Bagyalakshmi Muthan Thrilok Singh Rathore Vittal Ravishankar Rai 《Journal of Forest Research》2006,11(3):147-151
In vivo micrografting of Santalum album was achieved (50%) by grafting 4- to 5-cm-long scions, collected from a candidate plus tree (CPT) of 50–60 years of age,
onto 90-day-old nursery-grown rootstock. Scion size, rootstock age, and scion collection season were found to influence graft
success. Grafted plants were incubated under greenhouse conditions for 6–8 weeks during the graft union process. In vitro
micrografts were achieved by placing 1- to 2-cm-long scions derived from nodal shoot segments (collected from CPT) onto the
hypocotyl of 45-day-old in vitro rootstocks. Use of in vitro grown shoots as a source of scion gave better graft success (60%)
than scions collected directly from field-grown trees. In vitro grafting was also influenced by scion size and rootstock age.
Under favorable conditions, scions and hypocotyls unite to form complete plants that produced two to four leaves after 6–8
weeks. This is the first report on in vivo and in vitro micrografting of S. album having potential for production of disease-free clonal plants for conservation and improvement targets. 相似文献
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Rao AR Sarada R Baskaran V Ravishankar GA 《Journal of agricultural and food chemistry》2006,54(13):4593-4599
Botryococcus braunii is a green colonial microalga that is used mainly for the production of hydrocarbons, exopolysaccharides, and carotenoids. In the present study, the antioxidant properties of acetone extracts of B. braunii were evaluated using in vitro model systems such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxy radical scavenging, and lipid peroxidation in human low-density lipoprotein and rat tissues. Acetone extracts of B. braunii (equivalent to 10 ppm total carotenoid) exhibited 71 and 67% antioxidant activity in DPPH and hydroxyl radical scavenging model systems, respectively. Similarly, the extract also showed 72, 71, and 70% antioxidant activity in the liver, brain, and kidney of rats. Low-density lipoprotein oxidation induced by Cu2+ ions was also protected (22, 38, and 51%) by the algal extract in a dose-dependent manner (4, 6, and 8 ppm levels of total carotenoid). Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney of rats was also significantly decreased in B. braunii treated samples compared with those of control. Carotenoids (violaxanthin, astaxanthin, lutein, zeaxanthin, chlorophylls a and b, and alpha, beta-carotene) identified in the B. braunii acetone extract may be exhibiting antioxidant activity. Among the carotenoids, lutein represents more than 75% of the total carotenoids. B. braunii extract was shown to be effective for protecting biological systems against various oxidative stresses in vitro. This is the first report on the antioxidant properties of B. braunii. 相似文献
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Effects on survival and bacterial community composition of the aquaculture water and gastrointestinal tract of shrimp (Litopenaeus vannamei) exposed to probiotic treatments after an induced infection of acute hepatopancreatic necrosis disease
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Gustavo Pinoargote Gilberto Flores Kerry Cooper Sadhana Ravishankar 《Aquaculture Research》2018,49(10):3270-3288
Acute hepatopancreatic necrosis disease (AHPND) is a devastating condition impacting marine shrimp production worldwide. The objective of this study was to evaluate the effects of four probiotic formulations on Pacific white shrimp (Litopenaeus vannamei) infected with pathogenic Vibrio parahaemolyticus causing AHPND. In addition, bacterial community composition analyses of shrimp gastrointestinal tract (GIT) and aquaculture water before and after infection were conducted by sequencing variable region 4 of the 16S rRNA gene on the Illumina MiSeq platform. Treatments included: (1) Lactobacillus casei (P1), (2) L. casei and Rhodopseudomonas palustris (P2), (3) L. casei, Saccharomyces cerevisiae and R. palustris (P3), and (4) a commercial probiotic EM® (EM), which showed shrimp survival of 11.7%, 26.7%, 36.7% and 73.3% respectively. Treatments causing lower survival showed greater relative abundance (>60%) of family Vibrionaceae in the GIT compared to treatments with higher survival. Diversity indices from GIT samples revealed that treatments showing higher survival had higher Shannon index values (4.69 ± 0.133), compared with those of treatments with lower survival (0.17 ± 0.004). Diversity indices from water samples did not show significant differences after infection (Shannon index 4.64 ± 0.53). The results showed that probiotics could effectively mitigate AHPND while maintaining diverse microbial composition in shrimp GIT, thus maintaining sustainability in the shrimp aquaculture industry. 相似文献
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Sarada R Vidhyavathi R Usha D Ravishankar GA 《Journal of agricultural and food chemistry》2006,54(20):7585-7588
Haematococcus pluvialis is one of the potent organisms for production of astaxanthin, a high value ketocarotenoid. Astaxanthin is accumulated in thick-walled cyst cells of Haematococcus. The thick cell wall is made up of sporopollenin-like material, algaenan, which hinders solvent extraction of astaxanthin. In the present study, an improved method for extraction of astaxanthin without homogenization of cells is reported. Extractability of astaxanthin from cyst cells was evaluated by treating cells with various solvents and pretreating the cells with organic and mineral acids at 70 degrees C followed by acetone extraction. Hydrochloric acid treatment facilitated 86-94% extractability of astaxanthin. Treatment time, temperature, and concentration of the acid were found to be critical factors for maximum extractability. The treatment did not affect the astaxanthin ester profile and the treated cells can be preserved until further use. 相似文献