Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly diss...

The activity of usnic acid against Candida orthopsilosis and Candida parapsilosis on planktonic and biofilm conditions was investigated by using a broth microdilution and microplate methods. Potent in vitro activities against different Candida species were obtained. The metabolic activity of sessile cells of C. parapsilosis complex was reduced by 80% at four times the 80% inhibitory concentrati...

in this study, antioxidant and antimicrobial potentials of usnea intermedia, u. filipendula, and u. fulvoreagens and their stictic and usnic acid contents were investigated. antioxidant activity and total phenolic contents were evaluated in acetone, ethanol, and methanol extracts of these three species. antioxidant activity was measured by abts [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulp...

In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been teste...

There is a worldwide ongoing investigation for novel natural constituents with cytotoxic and antioxidant properties. The aim of this study was to investigate chemical profile and stated biological activities of the supercritical CO2 extract (SCE) of old man's beard compared to the extracts obtained using the conventional techniques (Soxhlet extracts and macerate). The most abundant compound ide...

The antimicrobial activity of the chloroform, diethyl ether, acetone, petroleum ether, and ethanol extracts of the lichen Cladonia foliacea and its (-)-usnic acid, atranorin, and fumarprotocetraric acid constituents against 9 bacteria and fungi has been investigated. The extracts and pure compounds alone were found active against the same bacteria and the same yeasts. Bacillus cereus, Bacillus ...

L-usnic acid inactivates urease through a process which implicates the blockade of--SH groups in parallel to the formation of inactive polymers. Both L-alanine and L-proline partially reverses the inactivation and effectively diminishes the amount of highly polymerized protein. The amino acids also prevent the linkage of L-usnic acid on the sites of low affinity for the ligand, being then relat...

L-usnic acid inactivates urease by formation of high molecular weight aggregates which can reached by a maximum of 880 000. L-cysteine partially reverses the inactivation of stimulating the appearance of active high molecular weight polymers. The existence of two class of binding points for L-usnic acid on the urease molecule is proposed, the first showing high affinity for the ligand, related ...