Combining UFLC-QTOF-MS analysis with biological evaluation of Centrosema coriaceum (Fabaceae) leaves.

Centrosema coriaceum Benth belongs to Fabaceae family and have few studies of biological activity and chemical composition. Thus, the aims of this work were to determine chemical profile of the ethanolic extract of C. coriaceum leaves (CCE) by UFLC-QTOF-MS and to evaluate its in vitro biological potential. CCE showed MIC value of 1000 µg/mL against Candida glabrata (fungistatic effect) and high affinity in cell envelope by increasing cell permeability in nucleotide leakage, sorbitol and ergosterol assays. CCE showed antioxidant activity in all assays performed. For the anti-inflammatory and cytotoxicity activities, CCE, at all tested concentrations, significantly inhibited the production of nitric oxide and did not decrease J774A.1 cell viability below 70%. Finally, rutin, kaempferol-3O-rutinoside, caffeic acid, and sucrose were identified in CCE by UFLC-QTOF-MS. These results suggest, for the first time, that C. coriaceum has interesting antifungal, antioxidant, and anti-inflammatory activities.

Toll-like receptor-7/8 agonist kill Leishmania amazonensis by acting as pro-oxidant and pro-inflammatory agent.

OBJECTIVES: Evaluation of the anti-Leishmanial activity of imidazoquinoline-based TLR7/8 agonists. METHODS: TLR7/8-active imidazoquinolines (2 and 3) were synthesized and assessed for activity against Leishmania amazonensis-intracellular amastigotes using mouse peritoneal macrophages. The production of reactive oxygen species (ROS), nitric oxide (NO) and cytokines was determined in infected and non-infected macrophages. KEY FINDINGS: The imidazoquinolines, 2 and 3, were primarily agonists of TLR7 with compound 3 also showing modest TLR8 activity. Docking studies showed them to occupy the same binding pocket on TLR7 and 8 as the known agonists, imiquimod and resiquimod. Compounds 2 and 3 inhibited the growth of L. amazonensis-intracellular amastigotes with the most potent compound (3, IC50 = 5.93 µM) having an IC50 value close to miltefosine (IC50 = 4.05 µM), a known anti-Leishmanial drug. Compound 3 induced macrophages to produce ROS, NO and inflammatory cytokines that likely explain the anti-Leishmanial effects. CONCLUSIONS: This study shows that activating TLR7 using compounds 2 or 3 induces anti-Leishmanial activity associated with induction of free radicals and inflammatory cytokines able to kill the parasites. While 2 and 3 had a very narrow cytotoxicity window for macrophages, this identifies the possibility to further develop this chemical scaffold to less cytotoxic TLR7/8 agonist for potential use as anti-Leishmanial drug.

ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification.

A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.