Antitubercular potential and pH-driven mode of action of salicylic acid derivatives.

In the search for new antituberculosis drugs with novel mechanisms of action, we evaluated the antimycobacterial activity of a panel of eight phenolic acids against four pathogenic mycobacterial model species, including Mycobacterium tuberculosis. We demonstrated that salicylic acid (SA), as well as the iodinated derivatives 5-iodo-salicylic acid (5ISA) and 3,5-diiodo-salicylic acid (3,5diISA), displayed promising antitubercular activities. Remarkably, using a genetically encoded mycobacterial intrabacterial pH reporter, we describe for the first time that SA, 5ISA, 3,5diISA, and the anti-inflammatory drug aspirin (ASP) act by disrupting the intrabacterial pH homeostasis of M.

Cell Type-Specific Anti- and Pro-Oxidative Effects of L. Ellagitannins.

Pomegranate and its by-products contain a broad spectrum of phytochemicals, such as flavonoids, phenolic acids and tannins, having pleiotropic preventive and prophylactic properties in health disorders related to oxidative stress and microbial contamination. Here, we examined the biological effects of a pomegranate peel ellagitannins-enriched (>90%) extract, PETE. In vitro studies revealed that PETE has a strong antiradical action towards synthetic radicals and biologically relevant ROS surpassing or comparable to that of Trolox.

Neurosimilator for Undergraduate Biophysics and Neurophysiology Courses.

Stringent animal welfare principles are forcing undergraduate instructors to avoid the use of animals. Therefore, many hands-on lab sessions using laboratory animals are progressively replaced by computer simulations. These versatile software simulations permit the observation of the behavior of biological systems under a great variety of experimental conditions.

Electrophysiological and spectroscopic investigation of hydrolysable tannins interaction with α-hemolysin of S. aureus.

In this study, using bilayer lipid membrane technique, we report a novel facet of antihemolytic activity of two tannins (1,2,3,4,5-penta-O-galloyl-β-D-glucose (PGG) and 1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (dGVG)), which consists in inhibiting the formation of α-hemolysin channels and blocking the conductivity of already formed channels. These effects were observed at tannin concentrations well below minimal inhibitory concentration values for S. aureus growth.

The Structural Changes in the Membranes of Caused by Hydrolysable Tannins Witness Their Antibacterial Activity.

Polyphenols, including tannins, are phytochemicals with pronounced antimicrobial properties. We studied the activity of two hydrolysable tannins, (i) gallotannin-1,2,3,4,5-penta-O-galloyl-β-D-glucose (PGG) and (ii) ellagitannin-1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (dGVG), applied alone and in combination with antibiotics against strain 8324-4. We also evaluated the effect of these tannins on bacterial membrane integrity and fluidity and studied their interaction with membrane proteins and lipids.