Inhibitory activities of 2-pyridinecarboxylic acid analogs on phytogrowth and enzymes

Production and characterization of a broad-spectrum antimicrobial 5-butyl-2-pyridine carboxylic acid from Aspergillus fumigatus nHF-01

The present study aims at the production optimization, purification, and characterization of a potent broad-spectrum antimicrobial compound (AMC) produced by Aspergillus fumigatus nHF-01 (GenBank Ac. No. MN190286). The culture conditions were optimized for a higher amount of AMC. The AMC was solvent extracted and characterized by UV–Vis, FT–IR, ESI–MS, and ¹H-NMR spectroscopy. The MIC, MBC and mode of action were determined against a set of Gram-positive and Gram-negative human pathogenic bacteria. Its antibiofilm, synergistic and cytotoxic effects were also tested. The putative target site of action was evaluated through in silico molecular docking study. The stain A. fumigatus nHF-01 produced the maximum AMC (5-butyl-2-pyridine carboxylic acid) in 2% MEB (w/v) and 4% YE (w/v) at pH 6.0 and 20 °C temperature with 100 rpm agitation for ten days. It caused complete lethality of the Gram-positive and Gram-negative human pathogenic bacteria at a 129 µg/mL dose by rupture and entire dissolution of cell integrity. It showed moderate antibiofilm activity and had a synergistic activity with streptomycin and additive effects with ciprofloxacin and vancomycin. It targets a respiratory enzyme, Quinol-Fumarate Reductase (1l0v), with the highest binding affinities. It had cytotoxicity against human lung carcinoma A549 cell line and was stable up to 100 °C. Thus, the study revealed that the strain A. fumigatus nHF-01 produces a potent broad-spectrum AMC 5-butyl-2-pyridine carboxylic acid that could be used against human food and topical pathogenic bacteria. This is the first report of such a compound produced from the A. fumigatus.

Progress in metallocarboxypeptidases and their small molecular weight inhibitors

In what corresponds to a life span, metallocarboxypeptidases (MCPs) have jumped from being mere contaminants in animal pancreas powders (in depression year 1929) to be key players in cellular and molecular processes (in yet-another-depression years 2009-2010). MCPs are unique zinc-dependent enzymes that catalyze the breakdown of the amide bond at the C-terminus of peptide and protein substrates and participate in the recovery of dietary amino acids, tissue organogenesis, neurohormone and cytokine maturation and other important physiological processes. More than 26 genes code for MCPs in the human genome, many of them still waiting to be fully understood in terms of physiological function. A variety of MCPs have been linked to diseases in man: acute pancreatitis and pancreas cancer, type 2 diabetes, Alzheimer's Disease, various types of cancer, and fibrinolysis and inflammation. Many of these discoveries have been made possible thanks to recent advances, as exemplified by plasma carboxypeptidases N and B, known for fifty and twenty years, respectively, which have had their structures released only very recently. Plasma carboxypeptidase B is a biological target for therapy because of its involvement in the coagulation/fibrinolysis processes. Besides, the widespread use of carboxypeptidase A as a benchmark metalloprotease since the early days of Biochemistry has allowed the identification and design of an increasingly vast repertory of small molecular weight inhibitors. With these two examples we wish to emphasize that MCPs have become part of the drug discovery portfolio of pharmaceutical companies and academic research laboratories. This paper will review key developments in the discovery and design of MCP small molecular weight inhibitors, with an emphasis on the discovery of chemically diverse entities. Although encouraging advances have been achieved in the last few years, the specificity and oral bioavailability of the new chemotherapeutic agents seem to pose a challenge to medicinal chemists.