Diastereoselective Synthesis of 3,4-Dihydropyran-3-carboxamides with in Vitro Anti-inflammatory Activity.

A versatile and economical reaction of diketene (1), aryl amines 2, cyclic 1,3-diketones 3, primary amines 4, and aryl aldehydes 5 was explored to synthesize 3,4-dihydropyran-3-carboxamide derivatives under mild conditions. Three stereogenic centers are generated in the products, and the structure of the major diastereomer of 6{1,1,3,1} was identified by X-ray diffraction and 2D NMR spectroscopy. The scope and limitation investigation provided two series of (2S,3R,4S)-chromene-3-carboxamides in good to excellent yields with high diastereoselectivity. Two products, 6{5,3,1,1} and 6{7,3,1,1}, exhibited in vitro anti-inflammatory activity with significant inhibition of pro-inflammatory cytokine IL-6 and TNF-α expression in lipopolysaccharide (LPS)-treated Raw 264.7 cells.

Semi-preparative separation of dihydromyricetin enantiomers by supercritical fluid chromatography and determination of anti-inflammatory activities.

Dihydromyricetin, extracted from Ampelopsis grossedentata, has been widely used as one of Chinese health products in recent years. However, limited chiral separation method hinders the studies of pharmacological and pharmacokinetic activity differences of (+)-dihydromyricetin, (-)-dihydromyricetin, and (±)-dihydromyricetin. Herein, we developed a supercritical fluid chromatography approach for chiral separation of dihydromyricetin. Firstly, effects of chiral stationary phase, co-solvent, and flow rate of mobile phase have been investigated in detail. The resolution of 5.11 was achieved for dihydromyricetin enantiomers on amylose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase with the CO2-methanol mixture (60:40, v/v). With respect to the enantiomeric purity, production rate and solvent consumption of 15 stacked injections, sample loading for semi-preparative separation of dihydromyricetin was optimized in three given equivalents set by volume overloading. Along with increase of sample loading per injection from 40 mg to 120 mg, the productivity of dihydromyricetin increased from 0.07 g (racemate)/g (chiral stationary phase) /24 h to 0.27 g (racemate) /g (chiral stationary phase)/24 h, and the consumption of methanol significantly reduced from 5.86 L/g (racemate) to 1.76 L/g (racemate). Moreover, (-)-dihydromyricetin exhibited better anti-inflammatory activity in TLR 2-related Raw 264.7 cells than (+)-dihydromyricetin and (±)-dihydromyricetin.

Structure-activity relationship study and biological evaluation of SAC-Garlic acid conjugates as novel anti-inflammatory agents.

A series of S-allyl-l-cysteine (SAC) with garlic acid conjugates as anti-inflammatory agents were designed and synthesized. Among the 40 tested compounds, SMU-8c exhibited the most potent inhibitory activity to Pam3CSK4-induced nitric oxide (NO) in RAW264.7 macrophages with IC50 of 22.54 ±â€¯2.60 µM. The structure-activity relationship (SAR) study suggested that the esterified carboxyl group, carbon chain extension and methoxylation phenol hydroxy could improve the anti-inflammatory efficacy. Preliminary anti-inflammatory mechanism studies showed that SMU-8c significantly down-regulated the levels of Pam3CSK4 triggered TNF-α cytokine in human THP-1 cells, mouse RAW 264.7 macrophages, as well as in ex-vivo human peripheral blood mononuclear cells (PBMC) with no influence on cell viability. SMU-8c specifically blocked the Pam3CSK4 ignited secreted embryonic alkaline phosphatase (SEAP) signaling with no influence to Poly I:C or LPS triggered TLR3 or TLR4 signaling. Moreover, SMU-8c suppressed TLR2 in HEK-Blue hTLR2 cells and inhibited the formation of TLR1-TLR2, and TLR2-TLR6 complex in human PBMC. In summary, SMU-8c inhibited the TLR2 signaling pathway to down-regulate the inflammation cytokines, such as NO, SEAP and TNF-α, to realize its anti-inflammatory activity.

Synthesis, structure-activity relationships and preliminary mechanism study of N-benzylideneaniline derivatives as potential TLR2 inhibitors.

Toll-like receptor 2 (TLR2) can recognize pathogen-associated molecular patterns to defense against invading organisms and has been represents an attractive therapeutic target. Until today, none TLR2 small molecule antagonist have been developed in clinical trial. Herein, we designed and synthesized 50 N-benzylideneaniline compounds with the help of CADD. And subsequent in vitro studies leading to the optimized compound SMU-A0B13 with most potent inhibitory activity to TLR2 (IC50=18.21 ±â€¯0.87 µM). Preliminary mechanism studies indicated that this TLR2 inhibitor can work through the NF-κB signaling pathway with high specificity and low toxicity, and can also efficiently downregulate inflammatory cytokines, such as SEAP, TNF-α and NO in HEK-Blue hTLR2, human PBMC and Raw 264.7 cell lines. Additionally, the docking situation also indicate SMU-A0B13 can well bind to the TLR2-TIR (PDB: 1FYW) active domain, which probably explains the bioactivity.