Design, synthesis and bioevaluation of PI3Kα-selective inhibitors as potential colorectal cancer drugs.

The dysregulation of the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin signaling pathway has been implicated in various human cancers, and isoform-selective inhibitors targeting PI3Kα have received significant interest in recent years. In this study, we have designed and synthesized three series of substituted benzoxazole derivatives based on the clinical candidate TAK-117 (8a). A detailed structure-activity relationship (SAR) study has identified the optimal compound 18a bearing a quinoxaline scaffold. Compared to the control 8a, 18a exhibited 4.4-fold more potent inhibitory activity against PI3Kα (IC50: 2.5 vs 11 nM) and better isoform-selective profiles over other PI3Ks. In addition, 18a showed a 1.5-fold more potent antiproliferative effect against HCT-116 cell lines (IC50: 3.79 vs 5.80 µM) and a better selectivity over the normal tissue cells. The potential antitumor mechanism and in vitro metabolic stability of 18a were also investigated. Notably, pharmacokinetic assays indicated that 18a had a higher plasma exposure, a higher maximum concentration and shorter elimination time compared to 8a.

Virtual screening of novel mTOR inhibitors for the potential treatment of human colorectal cancer.

The abnormal activation of the mTOR pathway is closely related to the occurrence and progression of cancer, especially colorectal cancer. In this study, a rational virtual screening strategy has been established and MT-5, a novel mTOR inhibitor with a quinoline scaffold, was obtained from the ChemDiv database. MT-5 showed potent kinase inhibitory activity (IC50: 8.90 µM) and antiproliferative effects against various cancer cell lines, especially HCT-116 cells (IC50: 4.61 µM), and this was 2.2-fold more potent than that of the cisplatin control (IC50: 9.99 µM). Western blot, cell migration, cycle arrest, and apoptosis assays were performed with HCT-116 cells to investigate the potential anticancer mechanism of MT-5. Metabolic stability results in vitro indicated that MT-5 exhibited good stability profiles in artificial gastrointestinal fluids, rat plasma, and liver microsomes. In addition, the key contribution of the residues around the binding pocket of MT-5 in binding to the mTOR protein was also investigated from a computational perspective.

Cobalt-promoted synthesis of sulfurated oxindoles via radical annulation of N-arylacrylamides with disulfides.

An efficient radical annulation of N-arylacrylamides with disulfides is developed for the synthesis of sulfurated oxindoles. The reaction occurs in a facile manner using CoBr2 as both an initiator and a promoter for the first time and (NH4)2S2O8 as the oxidant. By controlling the CoBr2/(NH4)2S2O8 ratio, a wide range of sulfurated and brominated/sulfurated oxindoles are selectively prepared in good to excellent yields. The present protocol is simple and highly atom economical, and can tolerate a broad range of substrates.

Iron-Catalyzed Radical Annulation of Unsaturated Carboxylic Acids with Disulfides for the Synthesis of γ-Lactones.

An efficient aerobic iron-catalyzed annulation of unsaturated carboxylic acids with disulfides has been developed. This procedure proceeds using FeCl3 as the catalyst and KI as an iodine source under an air atmosphere, which provides practical access to a wide range of substituted γ-lactone derivatives. The disclosed method is quite simple, highly atom-economic, environmentally friendly, and tolerates a broad substrate scope.

Rhizoma Bletillae polysaccharide elicits hemostatic effects in platelet-rich plasma by activating adenosine diphosphate receptor signaling pathway.

Rhizoma Bletillae, the tubes of Bletilla striata, has been traditionally used in China as a hemostatic agent. In preliminary studies, the major active fraction responsible for its hemostatic effect have been confirmed to be Rhizoma Bletillae polysaccharide (RBp), but the hemostatic mechanism of action of RBp is still unknown.The main aim of this study was to clarify its mechanism of hemostatic effect. RBp was prepared by 80 % ethanol precipitation of the water extract of Rhizoma Bletillae followed by the Sevag method to remove proteins. The average molecular weight (Mw) of the crude RBp maintained at a range of 30.06-200 KDa. The hemostatic effects of RBp were evaluated by testing its effect on the platelet aggregation of rat platelet-rich plasma (PRP). PRP was dealt with different concentrations of RBp and platelet aggregation was measured by the turbidimetric method. The hemostatic mechanism of RBp was investigated by examining its effect on platelet shape, platelet secretion, and activation of related receptors (P2Y1, P2Y12 and TXA2) by electron microscopy and the turbidimetric method. RBp significantly enhanced the platelet aggregations at concentrations of 50-200 mg/L in a concentration-dependent manner. The inhibitory rate of platelet aggregation was significantly increased by apyrase and Ro31-8220 in a concentration-dependent manner, while RBp-induced platelet aggregation was completely inhibited by P2Y1, P2Y12 and the PKC receptor antagonists. However, the aggregation was not sensitive to TXA2. RBp, the active ingredients of Rhizoma Bletillae responsible for its hemostatic effect, could significantly accelerate the platelet aggregation and shape change. The hemostatic mechanism may involve activation of the P2Y1, P2Y12, and PKC receptors in the adenosine diphosphate (ADP) receptor signaling pathway.

Organocatalytic Asymmetric α-Sulfenylation of 2-Substituted Indolin-3-ones: A Strategy for the Synthesis of Chiral 2,2-Disubstituted Indole-3-ones with S- and N-Containing Heteroquaternary Carbon Stereocenter.

An organocatalytic asymmetric α-sulfenylation of 2-substituted indolin-3-ones with N-(alkylthio or arylthio)succinimides has been developed for the first time using Cinchona-derived squaramide as the catalyst. Various chiral 2,2-disubstituted indole-3-ones with S- and N-containing heteroquaternary carbon stereocenters were obtained with up to 98% yield and 99% ee.

In vivo and in vitro anti-inflammatory effects of ethanol fraction from Periploca forrestii Schltr.

OBJECTIVE: To determine the anti-inflflammatory effects of an ethanol fraction of Periploca forrestii Schltr. (EFPF) and to investigate the potential mechanisms underlying in vivo and in vitro models. METHODS: The antiinflflammatory effects of EFPF were evaluated using the xylene-induced mouse ear edema and carrageenan-induced rat paw edema models in vivo. In vitro, RAW264.7 cells were exposed to 0-800 µg/mL EFPF and the cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Then cells were treated with different concentrations of EFPF (100-400 µg/mL) and stimulated with lipopolysaccharide (LPS, 1 µg/mL) for 24 h. The supernatant was analyzed for nitric oxide (NO) using the Griess reagent, and the levels of inflflammatory mediators and cytokines were determined using enzyme-linked immunosorbent assays for prostaglandin E2 (PGE2), tumor necrosis factor α (TNF-α), interleukin (IL) 6, and IL-10. The protein expressions of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor κB (NF-κB), and mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK were examined by Western blot. RESULTS: Compared with the control group, EFPF signifificantly reduced mouse ear edema and rat paw edema rate (P<0.05 or P<0.01). Compared with the LPS group, EFPF signifificantly inhibited the LPS-stimulated production of NO, PGE2, TNF-α and IL-6 (P<0.05 or P<0.01), and increased the IL-10 production (P<0.05). EFPF also signifificantly inhibited LPS-induced protein expressions of iNOS and COX-2, suppressed the phosphorylation and degradation of inhibitor of NF-κB-α, decreased p65 level, and inhibited the phosphorylation of p38, ERK1/2 and JNK P<0.05 or P<0.01). CONCLUSION: EFPF exerted anti-inflflammatory effect by reducing protein expressions of iNOS and COX-2 and the production of the inflflammation factors, including TNF-α, IL-6, NO and PGE2, mainly through inhibition of LPS-mediated stimulation of NF-κB and MAPK signaling pathways.

[Quality evaluation of bletillae rhizoma based on hemostatic biopotency].

This dissertation is to determine the biopotency of hemostat which processed in different places by establishing a bioassay method of Bletillae Rhizoma based on the thrombin time. Contrast test is the main methodology. Specifically, the reference substance of Bletillae Rhizoma is determined by comparing with the control substance of vitamin K1 using thrombin time, which is calibrated the Bletillae Rhizoma. The hemostatic biopotency is calculated by using the method of "parallel line assay method based on quantitative responses" (3.3) from different processed products. It indicates that there is a strong linear correlation between Bletillae Rhizoma and control drugs (Y = 66.332-23.913X, R2 = 0.995 3). The hemostatic biopotency of Bletillae Rhizoma from different processed products ranged between 821.93-1 187.53 U x g(-1) shown in the paper, and all of them can meet the requirements of the test. The methodology has an appropriate instrument precision (RSD 3.8%), intermediate precision (RSD 4.6%), repeatability (RSD 3.2%) and stability (RSD 3.7%). Therefore, it can be turned out that the methodology which established in the dissertation is good at determinating the hemostatic biopotency of Bletillae Rhizoma and it is reliable, simple and repeatable.