Cobalt-Catalyzed Asymmetric Deuteration of α-Amidoacrylates for Stereoselective Synthesis of α,ß-Dideuterated α-Amino Acids.

A cobalt-catalyzed deuteration of amidoacrylates using deuterated methanol afforded α,ß-dideuterio-α-amino esters in excellent enantiomeric ratios (mostly >95 : 5) and almost complete deuteration (99 %). The new protocol was used to prepare dideuterio-α-amino acid fragments in some drugs. Furthermore, the stereoselective deuteration was applied in a concise synthesis of dideuterio l-DOPA.

Design, synthesis and biological evaluation of novel 3,4-dihydro-2(1H)-quinolinone derivatives as potential chitin synthase inhibitors and antifungal agents.

A series of 3,4-dihydro-2(1H)-quinolinone derivatives contained butenediamide fragment were designed and synthesized. Their inhibition potency against chitin synthase and antimicrobial activities were screened in vitro. The enzymatic assays showed that all the synthesized compounds had inhibition potency against chitin synthase at concentration of 300 µg/mL. Compound 2d displayed excellent potency with inhibition percentage (IP) value of 82.3%, while IP value of the control polyoxin B was 87.5%. Compounds 2b, 2e and 2s whose IP values were above 70% showed good inhibition potency against chitin synthase. Moreover, the IC50 value of 2b was comparable with that of polyoxin B (0.09 mM). The Ki of compound 2b was 0.12 mM and the result from Lineweaver-Burk plot showed that 2b was non-competitive inhibitor to bind chitin synthase. The antifungal experiment showed that these compounds had excellent antifungal activity against fungal strains, especially for candida albicans. The antifungal activities against C .albicans of compounds 2b, 2d, 2e and 2l were comparable with that of fluconazole and were superior to that of polyoxin B. Meanwhile, the other compounds against C. albicans showed better antifungal activity (MIC 2 µg/mL) than polyoxin B except for compound 2n (MIC 4 µg/mL). The trial of drug combination use showed that these synthesized compounds had synergistic effects with fluconazole and polyoxin B. It indicated that these compounds were not competing with polyoxin B to bind with chitin synthase, which was also consistence with the result of enzymatic assays. The antibacterial experiment showed that these compounds had no activity against selected strains including three Gram-positive and three Gram-negative bacteria. These results showed that the designed compounds were chitin synthase inhibitors and had selective antifungal activity.

Synthesis and biological evaluation of novel 3-substituted amino-4-hydroxylcoumarin derivatives as chitin synthase inhibitors and antifungal agents.

A series of novel 3-substituted amino-4-hydroxycoumarin derivatives have been designed and synthesized as chitin synthase (CHS) inhibitors. All the synthesized compounds have been screened for their CHS inhibition activity and antimicrobial activity in vitro. The enzymatic assay indicated that most of the compounds have good inhibitory activity against CHS, in which compound 6o with IC50 of 0.10 mmol/L had stronger activity than that of polyoxins B, which acts as control drug with IC50 of 0.18 mmol/L. As far as the antifungal activity is concerned, most of the compounds possessed moderate to excellent activity against some representative pathogenic fungi. Especially, compound 6b was found to be the most potent agent against Cryptococcus neoformans with minimal inhibitory concentration (MIC) of 4 µg/mL. Moreover, the results of antibacterial screening showed that these compounds have negligible actions to some tested bacteria. Therefore, these compounds would be promising to develop selective antifungal agents.

Synthesis and biological evaluation of novel phosphoramidate derivatives of coumarin as chitin synthase inhibitors and antifungal agents.

A series of novel phosphoramidate derivatives of coumarin have been designed and synthesized as chitin synthase (CHS) inhibitors. All the synthesized compounds have been screened for their chitin synthase inhibition activity and antimicrobial activity in vitro. The bioactive assay manifested that most of the target compounds exhibited good efficacy against CHS and a variety of clinically important fungal pathogens. In particular, compound 7t with IC50 of 0.08 mM against CHS displayed stronger efficiency than the reference Polyoxin B with IC50 of 0.16 mM. In addition, the apparent Ki values of compound 7t was 0.096 mM while the Km of Chitin synthase prepared from Candida tropicalis was 3.86 mM for UDP-N-acetylglucosamine, and the result of the Ki showed that the compounds was a non-competitive inhibitor of the CHS. As far as the antifungal activity is concerned, compounds 7o, 7r and 7t were highly active against Aspergillus flavus with MIC values in the range of 1 µg/mL to 2 µg/Ml while the results of antibacterial screening showed that these compounds have negligible actions to the tested bacteria. These results indicated that the design of these compounds as antifungal agents was rational.

Design, synthesis and evaluation of novel quinazoline-2,4-dione derivatives as chitin synthase inhibitors and antifungal agents.

A series of novel 1-methyl-3-substituted quinazoline-2,4-dione derivatives were designed, synthesized, and characterized by (1)H NMR, (13)C NMR and MS spectral data. Their inhibition against chitin synthase (CHS) and antifungal activities were evaluated in vitro. Results showed compounds 5b, 5c, 5e, 5f, 5j, 5k, 5l, and 5o had strong inhibitory potency against CHS. Compound 5c, which has the highest potency among these compounds, had a half-inhibition concentration (IC50) of 0.08mmol/L, while polyoxin B as positive drug had IC50 of 0.18mmol/L. These IC50 values of compounds 5i, 5m, 5n, and 5s were greater than 0.75mmol/L, which revealed that those compounds had weak inhibition activity against CHS. Moreover, most of these compounds exhibited moderate to excellent antifungal activities. In detail, to Candida albicans, the activities of compound 5g and 5k were 8-fold stronger than that of fluconazole and 4-fold stronger than that of polyoxin B; to Aspergillus flavus, the activities of 5g, 5l and 5o were16-fold stronger than that of fluconazole and 8-fold stronger than that of polyoxin B; to Cryptococcus neoformans, the minimum-inhibition-concentration (MIC) values of compounds 5c, 5d, 5e and 5l were comparable to those of fluconazole and polyoxin B. The antifungal activities of these compounds were positively correlated to their IC50 values against CHS. Furthermore, these compounds had negligible actions to bacteria. Therefore, these compounds were promising selective antifungal agents.

[Advance in studies on effective components in wheat bran and their pharmacological activities].

Wheat bran, as the testa of wheat, has a long history of medication. Modern studies have discovered that wheat bran contains dietary fiber, phenolic compounds, proteins, vitamins, minerals and many other compounds, and boasts wide pharmacological activities such as blood glucose reduction, hypertension reduction, lipid reduction, anti-oxidation, anti-bacteria, anti-inflammatory, antivirus, prevention of colon cancer and mutations, immunomodulation and adsorption of heavy metals. With great development and utilization values, wheat bran has long attracted wide attention from Chinese and foreign scholars. The paper summarizes the latest advance in domestic and foreign studies on effective components in wheat bran and their pharmacological effect, and gives a brief introduction of the limiting factors in the comprehensive development and utilization of wheat bran, in order to provide new preference for the development and utilization of abundant wheat bran resources in China.

Synthesis and biological evaluation of novel N-acyl substituted quinolin-2(1H)-one derivatives as potential antimicrobial agents.

A series of novel N-acyl substituted quinolin-2(1H)-one derivatives were synthesized and screened in vitro for their antibacterial and antifungal activities by disc diffusion method. All the compounds exhibited moderate to good antimicrobial activities, some of these compounds displayed comparable or better antibacterial or antifungal activities against some tested strains compared to the reference drugs Streptomycin and Fluconazole.