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Biomedical subjects

E Azaz

Publications and source records attributed to E Azaz.

12 recordsLinked to original sources
PubMed1985

Anticariogenic activity of licorice and glycyrrhizine I: Inhibition of in vitro plaque formation by Streptococcus mutans.

The effect of licorice and its active sweet component glycyrrhizin was tested on the growth and adherence to glass of the cariogenic Streptococcus mutans. Neither licorice nor glycyrrhizin promoted growth or induced plaque formation. In the presence of sucrose, glycyrrhizin did not affect bacterial growth, but the adherence (plaque formation) was markedly inhibited. At 0.5-1% glycyrrhizin, inhibition was almost complete. These results support our previous suggestions that glycyrrhizin might serve as an efficient vehicle for topical oral medications.

Anti-Bacterial Agents↗
PubMed1981

Hemolysis caused by polyoxyethylene-derived surfactants. Evidence for peroxide participation.

The hemolytic properties of nonionic surfactants of the series CH3(CH2)15-17-O-(CH2CH2O)nCH2CH2OH were investigated and compared to those of saponins, sapogenins and H2O2. Antioxidants and anaerobic conditions were shown to inhibit the hemolysis, while glycyrrhizin was found to enhance it. Similar effects were obtained for H2O2 hemolysis, but not for saponin and sapogenin hemolysis. It is proposed that peroxides and free radicals are mainly responsible for the polyoxyethylene derived surfactants induced hemolysis.

Animals↗
PubMed1978

Autoxidation of polysorbates.

Aqueous solutions of polysorbate 20 undergo autoxidation on storage, with the peroxide number increasing and subsequently decreasing again, the acidity increasing continuously, the pH and surface tension falling and tending to level off, and the cloud point dropping sharply until turbidity begins at room temperature. The changes are accelerated by light, elevation of temperature, and a copper sulfate catalyst. At the same time, hydrolysis occurs, liberating lauric acid. Analysis of the alterations in these properties leads to the conclusion that hydrolysis has the major influence near room temperature and that oxyethylene undergoes chain shortening at temperatures above 40 degrees. However, evidence of degradation is detectable even in previously unopened commercial samples of polysorbates 20, 40, and 60, warranting attention to the stability of and standards for these surfactants as compared with the solid alkyl ether type of nonionic surfactant.

Chemical Phenomena↗
PubMed1975

Surface tension and cloud point changes of polyoxyethylenic non-ionic surfactants during autoxidation.

Changes in the surface tension-concentration curves of the non-ionic surfactant cetomacrogol, a polyoxyethylenic (POE) hexadecyl ether containing about 24 ethylene oxide (EO) groups, have been examined during autoxidation of aqueous solutions. The curves exhibit decreases in cmc values and changes in the slopes below and above the cmc which lead to the loss of the sharp break characteristic of micelle-formation. There is also a progressive decrease in the cloud point during autoxidation. Surface tensions and cloud points of a series of known POE hexadecyl ethers containing from 10 to 60 EO units have been measured and related to the number of EO units present. From these data, it is apparent that autoxidation of cetomacrogol is accompanied by degradation of POE chain rather than the hydrocarbon chain, the number of EO units lost up to the time at which the solution becomes turbid being about 14. The significance of such measurements is discussed in relation to the detection of decomposition and pending rapid decomposition in synthesized and commercial surfactants.

Catalysis↗