Search results for "analytical"
showing 10 items of 9586 documents
Zanhasaponins A and B, Antiphospholipase A2 Saponins from an Antiinflammatory Extract of Zanha africana Root Bark
1997
A MeOH extract from Z. africana was examined for topical antiinflammatory activity and proved to be active against arachidonic acid (AA) acute edema, 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced chronic inflammation, and oxazolone delayed-type hypersensitivity in mice. The extract also showed significant inhibitory activity of Naja naja phospholipase A2 when a polarographic method was used. Two oleanane-type triterpene saponins, zanhasaponins A (1) and B (2), and the cyclitol pinitol (4), isolated from the extract, were active as inhibitors of PLA2. A further saponin, zanhasaponin C (3) was inactive in this assay.
Atomic fluorescence determination of total and inorganic arsenic species in beer
2001
A simple and nearly direct procedure has been developed for the determination of As in beers, based on hydride generation and atomic fluorescence detection. Using 2 mol l−1 HCl with a carrier flow of 6 ml min−1, 3% m/v NaBH4 with a flow of 1.3 ml min−1, a reaction coil of 200 cm and an argon flow of 400 ml min−1, total arsenic in beer could be determined in samples diluted 1∶10 with a final concentration of 2 mol l−1 HCl, 1% m/v KI and 0.08% v/v of an antifoam agent. For the estimation of AsIII and AsV concentrations in beer samples, the difference between the analytical sensitivities of the fluorescence signals obtained for As hydride, without and with previous treatment of samples with KI…
Antifungal steroid saponins from Dioscorea cayenensis.
2004
From the rhizomes of Dioscorea cayenensis Lam.-Holl (Dioscoreaceae), the new 26- O- beta- D-glucopyranosyl-22-methoxy-3 beta,26-dihydroxy-25( R)-furost-5-en-3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 1) was isolated together with the known dioscin ( 2) and diosgenin 3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 3). Their structures were established on the basis of spectral data. Compound 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of …
A Novel Series of Acylhydrazones as Potential Anti-Candida Agents: Design, Synthesis, Biological Evaluation and In Silico Studies
2019
In the context of an increased incidence of invasive fungal diseases, there is an imperative need of new antifungal drugs with improved activity and safety profiles. A novel series of acylhydrazones bearing a 1,4-phenylene-bisthiazole scaffold was designed based on an analysis of structures known to possess anti-Candida activity obtained from a literature review. Nine final compounds were synthesized and evaluated in vitro for their inhibitory activity against various strains of Candida spp. The anti-Candida activity assay revealed that some of the new compounds are as active as fluconazole against most of the tested strains. A molecular docking study was conducted in order to evaluate the …
Steroidal saponins from Smilax medica and their antifungal activity.
2005
Three new steroidal saponins (1-3) were isolated from the roots of Smilax medica, together with the known disporoside A (4). The structures of the new compounds were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS, and HRESIMS). Compounds 1, 2, and 4 demonstrated weak antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata, and C.tropicalis, with MIC values between 12.5 and 50 microg/mL.
Synthesis and Influence of 3-Amino Benzoxaboroles Structure on Their Activity against Candida albicans
2020
Benzoxaboroles emerged recently as molecules of high medicinal potential with Kerydin®
Synthesis, Properties and Antimicrobial Activity of 5-Trifluoromethyl-2-formylphenylboronic Acid
2020
2-Formylphenylboronic acids display many interesting features, not only from synthetic but also from an application as well as structural points of view. 5-Trifluoromethyl-2-formyl phenylboronic acid has been synthesized and characterized in terms of its structure and properties. The presence of an electron-withdrawing substituent results in a considerable rise in the acidity in comparison with its analogues. In some solutions, the title compound isomerizes with formation of the corresponding 3-hydroxybenzoxaborole. Taking into account the probable mechanism of antifungal action of benzoxaboroles, which blocks the cytoplasmic leucyl-tRNA synthetase (LeuRS) of the microorganism, docking stud…
Chemical and antifungal investigations of six Lippia species (Verbenaceae) from Brazil
2012
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Bioactive Steroidal Saponins from Smilax medica
2006
Two new spirostanol saponins ( 1 and 2) were isolated from the roots of Smilax medica, together with the known smilagenin 3-O-beta-D-glucopyranoside (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR experiments. Compounds 1 and 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs between 6.25 and 50 microg/mL) whereas 3 was inactive.
Synthesis and biological evaluation of pyridinebetaine A and B
2009
The synthesis of the marine natural products pyridinebetaine A and B is reported. The biological evaluation of pyridinebetaine A and B and several analogues as cytotoxic, antifungal and antiviral agents is also described. Unfortunately, none of the compounds tested showed relevant antifungal or cytotoxic activity. Only pyridinebetaine B reduced the Herpes simplex virus type 1 virus replication, though only weakly.