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Solvent Fractions (solvent + fraction)
Selected AbstractsSuppression of Root Rotting Fungi and Root Knot Nematode of Chili by Seaweed and Pseudomonas aeruginosaJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2008V. Sultana Abstract Solvent fractions (i.e. n -hexane, chloroform and methanol) of the ethanol extracts of the seaweeds Codium iyengarii, Jania capillacea, Stokeyia indica and Solieria robusta caused more than 50% mortality of Meloidogyne javanica juveniles within 24 h at 10 mg/ml. Nematode mortality increased with an increase in fraction concentration or exposure time. The n -hexane fractions from S. indica, J. capillacea and C. iyengarii and the chloroform fraction from S. robusta also resulted in more than 50% mortality within 48 h at 1.0 mg/ml. In a screen-house experiment application of S. indica and S. robusta as soil amendments alone or with Pseudomonas aeruginosa, a plant growth promoting rhizobacterium (PGPR), significantly suppressed infection of chili roots by root-infecting fungi Macrophomina phaseolina, Rhizoctonia solani, Fusarium solani and the root knot nematode Meloidogyne javanica. Seaweed alone or with PGPR also increased plant growth. Suppressive effect on root pathogens and growth enhancement potential of seaweeds and P. aeruginosa were also effective in field plots. [source] Drug encapsulation using supercritical fluid extraction of emulsionsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2006P. Chattopadhyay Abstract The current work was aimed at evaluating a new method, supercritical fluid extraction of emulsions (SFEE), for the production of composite (e.g., polymer-drug) micro- and nanoparticles, intended for application in sustained-release drug delivery formulations. Using the proposed method, composite particles were obtained, both in a continuous or batch manner by supercritical carbon dioxide extraction of oil-in-water (o/w) emulsions. Model drugs indomethacin and ketoprofen and biodegradable polymers poly(lactic/glycolic) acid and Eudragit RS were used in order to demonstrate the effectiveness of the SFEE process for producing these particles. Stable aqueous suspensions of composite micro and nanoparticles, having sizes ranging between 0.1 and 2 µm were consistently obtained. Emulsion droplet diameter was found to be the major size control parameter. Other parameters investigated included polymer and drug concentrations in solvent and emulsion solvent fraction. The residual solvent content in the particle suspension obtained was consistently below 50 ppm. Standard dissolution tests were used to observe the sustained release phenomenon of the composite particles. The dissolution profile was characterized in terms of the intrinsic dissolution kinetic coefficients taking into account the specific surface area and solubility of the particles. It was observed that the kinetic coefficient parameter for encapsulated drugs was reduced by 2,4 orders of magnitude when compared to the unprocessed drug particles. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:667,679, 2006 [source] Crystallization of type I chloramphenicol acetyltransferase: an approach based on the concept of ionic strength reducersACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2000Antonina E. Andreeva Chloramphenicol acetyltransferase (CAT) is responsible for bacterial resistance to chloramphenicol. It catalyzes inactivation of the antibiotic by acetyl-group transfer from acetyl CoA to one or both hydroxyl groups of chloramphenicol. Type I CAT possesses some unique properties which are not observed in other CAT variants. Type I CAT overexpressed in Escherichia coli was purified and crystals with a resolution limit of 2.22,Å have been obtained using a novel procedure which is based on the concept of `ionic strength reducers'. The crystals have the symmetry of space group P1 and unit-cell parameters a = 96.46, b = 113.86, c = 114.21,Å, , = 119.9, , = 94.1, , = 98.6°. These dimensions are consistent with four to six trimers per unit cell, corresponding to a solvent fraction ranging from 65 to 47%. [source] Radical scavenging and anti-inflammatory activity of extracts from Opuntia humifusa Raf.JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2006J. Y. Cho Opuntia humifusa Raf. (O. humifusa Raf.) is a member of the Cactaceae family. To determine the antioxidative and anti-inflammatory effects of this herb, various solvent fractions (methanol, hexane, chloroform, ethyl acetate, butanol, and water) prepared from the leaves of cacti were tested using DPPH (2,2-diphenyl-l-picrylhydrazyl radical) and xanthine oxidase assays, and nitric oxide (NO)-producing macrophage cells. We found that O. humifusa Raf. displayed potent antioxidative and anti-inflammatory activity. Thus, all solvent fractions, except for the water layer, showed potent scavenging effects. The scavenging effect of the ethyl acetate fraction was higher than that of the other fractions, with IC50 values of 3.6 and 48.2 ,g mL,1. According to activity-guided fractionation, one of the active radical scavenging principles in the ethyl acetate fraction was found to be quercetin. In contrast, only two fractions (chloroform and ethyl acetate) significantly suppressed nitric oxide production from the lipopolysaccharide (LPS)-activated RAW264.7 cells. In addition, chloroform and ethyl acetate fractions significantly blocked the expression of inducible nitric oxide synthetase (iNOS) and interleukin-6 (IL-6) from the RAW264.7 cells stimulated by LPS. Moreover, ethyl acetate fractions significantly blocked the expression of IL-1, from the RAW264.7 cells stimulated by LPS. Therefore, the results suggested that O. humifusa Raf. may modulate radical-induced toxicity via both direct scavenging activity and the inhibition of reactive species generation, and the modulation of the expression of inflammatory cytokines. Finally, O. humifusa Raf. may be useful as a functional food or drug against reactive species-mediated disease. [source] Antitumor activity of chloroform fraction of Scutellaria barbata and its active constituentsPHYTOTHERAPY RESEARCH, Issue 9 2007Jianqing Yu Abstract Scutellaria barbata (SB) is widely used as an antitumor agent in China, but the antitumor components of SB are still unclear. The antitumor activity of various fractions of an ethanol extract of SB was studied in six human malignant cell lines. Bio-based assays showed that non-polar and low-polar solvent fractions of SB had dose-dependent cytotoxicities on six cancer cell lines. The IC50 values of these fractions on the cancer cell lines tested ranged from 16 to 70 µg/mL after 48 h of treatment. Among them, the chloroform fraction (CE-SB) had the strongest cytotoxicity on cancer cell lines with a lower cytotoxic effect on a normal liver cell line. Bel-7402 cell apoptosis induced by CE-SB was examined using Hoechst 33258 staining, agarose gel electrophoresis and flow cytometry. CE-SB dose-dependently decreased the S phase content. Treatment with CE-SB caused cytochrome c release and activation of caspase-9. The antitumor activity of CE-SB in vivo was also evaluated. At 60 mg/kg/day, CE-SB significantly inhibited the solid tumor proliferation and increased the life span of ascites tumor bearing mice (p < 0.01). CE-SB was subjected to bioassay-guided isolation of the active compounds by chromatography on silica gel and Sephadex LH-20. Phytol, wogonin, luteolin and hispidulin were obtained as cytotoxic constituents. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||