Search results for "glycoside"
showing 10 items of 296 documents
Isolation and characterization of Saccharomyces cerevisiae mutants resistant to aculeacin A
1991
Aculeacin A is a lipopeptide that inhibits beta-glucan synthesis in yeasts. A number of Saccharomyces cerevisiae mutants resistant to this antibiotic were isolated, and four loci (ACR1, ACR2, ACR3, and ACR4) whose products are involved in the sensitivity to aculeacin A of yeast cells were defined. Mutants containing mutations in the four loci were also resistant to echinocandin B, another member of this lipopeptide family of antibiotics. In contrast, acr1, acr3, and acr4 mutants were resistant to papulacandin B (an antibiotic containing a disaccharide linked to two fatty acid chains that also inhibits beta-glucan synthesis), but acr2 mutants were susceptible to this antibiotic. This result …
A New Phenanthrene Glycoside and Other Constituents from Dioscorea opposita
2005
Phytochemical investigation of the rhizome of Dioscorea opposita has led to the isolation of a new phenanthrene glycoside, 3,4,6-trihydroxyphenanthrene-3-O-beta-D-glucopyranoside (1), and five known compounds, soyacerebroside I (2), adenosine (3), beta-sitosterol (4), palmitic acid (5) and palmitoyloleoylphosphatidylcholine (6). Their structures were determined by spectroscopic methods, including 1D- and 2D-NMR. Compounds 1-6 exhibited no antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis.
Formation of a new cell wall by protoplasts of Candida albicans: effect of papulacandin B, tunicamycin and Nikkomycin.
1987
SUMMARY: Incorporation of polysaccharides into the walls of regenerating protoplasts of Candida albicans was followed in the presence of papulacandin B, tunicamycin and nikkomycin. With the first drug, chitin was incorporated normally whereas incorporation of glucans and mannoproteins was significantly decreased. Tunicamycin decreased incorporation of all wall polymers when added at the beginning of the regeneration process but blocked only mannan and alkali-insoluble glucan incorporation when added after 5 h. Nikkomycin inhibited chitin synthesis, and the walls formed by the protoplasts were enriched in alkali-soluble glucan. Pulse-chase experiments suggested that a precursor-product relat…
Steroidal saponins from Asparagus acutifolius.
2007
Abstract Six new steroidal saponins ( 1 – 6 ) were isolated from the roots of A. acutifolius L., together with a known spirostanol glycoside ( 7 ). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS and HRESIMS). Compounds 4 – 7 demonstrated antifungal activity against the human pathogenic yeasts C. albicans , C. glabrata and C. tropicalis with MICs values between 12.5 and 100 μg/ml.
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.
A kinetic study on the regeneration ofCandida albicansprotoplasts in the presence of cell wall synthesis inhibitors
1993
Aculeacin A and papulacandin B block cell wall regeneration in Candida albicans protoplasts at an intermediate step in which the protoplasts have not yet synthesized the rigid structure of the cell wall and are therefore still osmotically sensitive. In the presence of the antibiotics, total synthesis of glucan is not significantly lowered with respect to control cells, although most of it appears either in the culture medium or in the regenerating wall as alkali-soluble glucan. Thus, it is proposed that echinocandins (such as aculeacin A) and papulacandins may not inhibit glucan synthesis per se but instead inhibit its incorporation into the supramolecular organization of the cell wall.
Bioactive saponins from plants: An update
2000
Plant saponins are a group of naturally occuring triterpene or steroid glycosides which include a large number of biologically and pharmacologically active compounds. Saponins have been shown in both in vitroand in vivoexperimental test systems during the last decade to possess a broad spectrum of biological and pharmacological activities. This review will summarize some of the recent advances concerning cancer-related activity, immunostimulating, immunoadjuvant, antihepatotoxic, antiphlogistic, antiallergic, molluscicidal, hemolytic, antifungal, antiviral, and hypoglycemic activities. In addition, the effects on the cardiovascular system and the central nervous system will be discussed tog…
Effect of Stevia rebaudiana addition on bioaccessibility of bioactive compounds and antioxidant activity of beverages based on exotic fruits mixed wi…
2015
In order to determine the impact of Stevia rebaudiana (SR) addition on bioactive compounds bioaccessibility of a new developed functional beverage based on exotic fruits (mango juice, papaya juice and acai) mixed with orange juice and oat, an in vitro gastrointestinal digestion was performed. Ascorbic acid, total carotenoids, total phenolics, total anthocyanins, total antioxidant capacity and steviol glycosides were evaluated before and after a simulated gastrointestinal digestion. Salivary and gastric digestion had no substantial effect on any of the major phenolic compounds, ascorbic acid, total antioxidant capacity and steviol glycosides, whereas carotenoids and anthocyanins diminished s…
Cooking influence on physico-chemical fruit characteristics of eggplant (Solanum melongena L.)
2016
Physico-chemical traits of three eggplant genotypes ("Tunisina", "Buia" and "L 305") were evaluated before and after two cooking treatments (grilling and boiling). Different genotypes revealed different changes after cooking, with "Tunisina" showing a better retention of phytochemicals with respect to other two genotypes. The main physical phenomena were water loss during grilling, and dry matter loss after boiling. Chlorogenic acid, the main phenolic in eggplant, resulted higher in grilled samples, while delphinidin glycosides resulted more retained in boiled samples. Glycoalkaloids, thiols and biogenic amines were generally stable, while 5-hydroxy-methyl-furfural was found only in grilled…
New pregnane and phenolic glycosides from Solenostemma argel.
2016
Abstract From the aerial parts, pericarps and roots of Solenostemma argel, three new pregnane glycosides (1–3) with two known ones and a new phenolic glycoside (4) have been isolated. Their structures were established by extensive 1D – and 2D NMR and mass spectroscopic analysis. The cytotoxicity of all compounds was evaluated against two human tumor cell lines (SW 480, MCF-7), but none of them was active in the concentration range 0.9–59.0 μM. Compounds 2 and the known argeloside F at non toxic concentrations for the PBMCs (27.3 μM and 27.6 μM, respectively) significantly decreased the Il-1β production by LPS-stimulated PBMCs. All isolated compounds showed a significant antioxidant potentia…