Preparation of 9-hydroxy grayanotoxin derivatives and their acute toxicity in mice.

Novel 9alpha and 9beta-hydroxy grayanotoxin II derivatives were prepared by photo-sensitized oxygenation of iso-grayanotoxin II and oxidation of grayanotoxin II tetraacetate with selenium dioxide respectively. The lethal dosage of 9alpha and 9beta-hydroxy grayanotoxin II were lower than that of grayanotoxin II. In addition, the lethal dosage of 9beta-hydroxy-dihydro grayanotoxin II was higher than that of dihydro grayanotoxin II.

Purification and characterization of a novel cholesterol esterase from Pseudomonas aeruginosa, with its application to cleaning lipid-stained contact lenses.

With the aim of developing a new cholesterol esterase for eliminating lipids on used contact lenses, microorganisms were screened for the enzyme activity. A Pseudomonas aeruginosa isolated from soil was found to produce a desirable enzyme. The enzyme had an isoelectric point of 3.

Mutagenicity of steviol and its oxidative derivatives in Salmonella typhimurium TM677.

Stevioside is natural non-caloric sweetner isolated from Stevia rebaudiana BERTONI, which has been used as a non-caloric sugar substitute in Japan. Pezzuto et al. demonstrated that steviol shows a dose-dependent positive response in forward mutation assay using Salmonella typhimurium TM677 in the presence of metabolic activation system (Aroclor induced rat liver S9 fraction).