Leishmanicidal Galloylquinic Acids are Noncompetitive Inhibitors of Arginase

The Inhibition of Arginase by Amino Acids*

In the course of an attempt to develop a rapid method for the enzymatic determination of arginine it was observed that a quantity of arginase, which would hydrolyze 31 mg. of pure arginine in less than 1 hour, took much longer to achieve the same performance within a, protein hydrolysate, 4 hours in the case of arachin, 5 in that of gelatin, and even more in that of casein. The obvious inferenc...

Leishmanicidal activity of Cecropia pachystachya flavonoids: arginase inhibition and altered mitochondrial DNA arrangement.

The plant Cecropia pachystachya Trécul is widely used in Brazilian ethnomedicine to treat hypertension, asthma, and diabetes. Arginase is an enzyme with levels that are elevated in these disorders, and it is central to Leishmania polyamine biosynthesis. The aims of this study were to evaluate antileishmanial activity and inhibition of the arginase enzyme by C. pachystachya extracts, and to stud...

Spontaneous Human Eosinophil Apoptosis Retinoic Acids Are Potent Inhibitors of

Unsaturated fatty acids are inhibitors of bacterial conjugation.

This report describes a high-throughput assay to identify substances that reduce the frequency of conjugation in Gram-negative bacteria. Bacterial conjugation is largely responsible for the spread of multiple antibiotic resistances in human pathogens. Conjugation inhibitors may provide a means to control the spread of antibiotic resistance. An automated conjugation assay was developed that used...

Retinoic acids are potent inhibitors of spontaneous human eosinophil apoptosis.

Retinoic acids (RAs), which are active metabolites of vitamin A, are known to enhance Th2-type immune responses in vitro, but the role of RAs in allergic inflammatory cells remains unclear. In this study, we demonstrated that purified peripheral blood eosinophils expressed nuclear receptors for RAs at the mRNA and protein levels. Eosinophils cultured with all-trans RA (ATRA) and 9-cis-RA showed...