Novel 4-aminoquinolines: Synthesis, inhibition of the Mycobacterium tuberculosis enoyl-acyl carrier protein reductase, antitubercular activity, SAR, and preclinical evaluation.

Herein a series of 4-aminoquinolines were synthesized in an attempt to optimize and study the structural features related to LABIO-17 biological activity, a Mycobacterium tuberculosis NADH-dependent enoyl-acyl carrier protein reductase (MtInhA) inhibitor previously identified by a virtual-ligand-screening approach. Structure-activity relationships led to novel submicromolar inhibitors of MtInhA and potent antitubercular agents. The lead compound is 87-fold more potent as enzymatic inhibitors and 32-fold more potent against M. tuberculosis H37Rv strain in comparison with LABIO-17. These molecules were also active against multidrug-resistant strains, devoid of apparent toxicity to mammalian cells and showed favorable in vitro ADME profiles. Additionally, these compounds were active in an intracellular model of tuberculosis (TB) infection, showed no genotoxicity signals, satisfactory absorption parameters and absence of in vivo acute toxicity. Finally, treatment with selected 4-aminoquinoline for two weeks produced bacteriostatic effect in a murine model of TB. Taken together, these findings indicate that this chemical class may furnish candidates for the future development of drug-sensitive and drug-resistant tuberculosis treatments.

Antitubercular Activity of Novel 2-(Quinoline-4-yloxy)acetamides with Improved Drug-Like Properties.

Using cycloalkyl and electron-donating groups to decrease the carbonyl electrophilicity, a novel series of 2-(quinoline-4-yloxy)acetamides was synthesized and evaluated as in vitro inhibitors of Mycobacterium tuberculosis (Mtb) growth. Structure-activity relationship studies led to selective and potent antitubercular agents with minimum inhibitory concentrations in the submicromolar range against drug-sensitive and drug-resistant Mtb strains. An evaluation of the activity of the lead compounds against a spontaneous qcrB mutant strain indicated that the structures targeted the cytochrome bc 1 complex. In addition, selected molecules inhibited Mtb growth in a macrophage model of tuberculosis infection. Furthermore, the leading compound was chemically stable depending on the context and showed good kinetic solubility, high permeability, and a low rate of in vitro metabolism. Finally, the pharmacokinetic profile of the compound was assessed after oral administration to mice. To the best of our knowledge, for the first time, a 2-(quinoline-4-yloxy)acetamide was obtained with a sufficient exposure, which may enable in vivo effectiveness and its further development as an antituberculosis drug candidate.

The Quinovic Acid Glycosides Purified Fraction from Uncaria tomentosa Protects against Hemorrhagic Cystitis Induced by Cyclophosphamide in Mice.

Uncaria tomentosa is widely used in folk medicine for the treatment of numerous diseases, such as urinary tract disease. Hemorrhagic cystitis (HE) is an inflammatory condition of the bladder associated with the use of anticancer drugs such as cyclophosphamide (CYP). Sodium 2-mercaptoethanesulfonate (Mesna) has been used to prevent the occurrence of HE, although this compound is not effective in established lesions. It has been demonstrated that the purinergic system is involved in several pathophysiological events. Among purinergic receptors, P2X7 deserves attention because it is involved in HE induced by CYP and, therefore, can be considered a therapeutic target. The objective of this study was to investigate the potential therapeutic effect of the quinovic acid glycosides purified fraction (QAPF) from U. tomentosa in the mouse model of CYP-induced HE. Pretreatment with QAPF not only had a protective effect on HE-induced urothelial damage (edema, hemorrhage and bladder wet weight) but was also able to control visceral pain, decrease IL-1ß levels and down-regulates P2X7 receptors, most likely by inhibit the neutrophils migration to the bladder. This research clearly demonstrates the promising anti-inflammatory properties of QAPF, supporting its use as complementary therapy. QAPF represents a promising therapeutic option for this pathological condition.