TRPV1 Receptor-Mediated Hypoglycemic Mechanism of Capsaicin in Streptozotocin-Induced Diabetic Rats.

Our previous research showed that capsaicin exhibits hypoglycemic effects by activating the transient receptor potential vanilloid 1 (TRPV1) channel in diabetic rats. Interestingly, capsiate was also able to activate the TRPV1 channel, but with a non-significant hypoglycemic effect. This study aimed to investigate the effect of capsaicin on the glycometabolism of streptozotocin (STZ)-induced diabetic rats by blocking the TRPV1 channel. After a 4-week capsaicin treatment (6 mg/kg·bw), the serum insulin level of STZ-induced diabetic rats increased from 15.2 to 22.1 mIU/L, the content of hepatic glycogen and muscle glycogen increased by 81.2 and 20.2%, respectively, and the blood glucose level decreased significantly from 19.3 to 14.7 mmol/L. When the TRPV1 channel was blocked, capsaicin lost the above-mentioned effects, and the hypoglycemic effect was no longer significant. It was concluded that a combined up-regulation of both TRPV1 receptors and pancreatic duodenal homeobox-1 (PDX-1) led to the hypoglycemic effect of capsaicin, which partially explains our previous observation: capsiate activating TRPV1 without showing a significant hypoglycemic effect was due to the lack of a significant up-regulation of PDX-1. Based on the experimental results, we speculated that two signaling pathways [TRPV1-(PDX1)-(GLUT2/GK) and TRPV1-(PDX-1)-(IRS1/2)] exist in the pancreas of STZ-induced diabetic rats.

Highly efficient asymmetric synthesis of 3-indolyl(hydroxy)acetates via Friedel-Crafts alkylation of indoles.

An efficient enantioselective Friedel-Crafts alkylation of indoles to ethyl glyoxylate catalyzed by chiral N,N'-dioxide-Sc(III) complex was developed. The corresponding 3-indolyl(hydroxy)acetates compounds were afforded in good yields with high enantioselectivities (up to 95% ee).

Chiral biphenylamide derivative: an efficient organocatalyst for the enantioselective synthesis of alpha-hydroxy phosphonates.

The aldol reactions of alpha-keto phosphonates and aldehydes were facilitated by an axially chiral biphenylprolinamide under mild conditions, affording the synthetically and pharmaceutically useful products in high yields and excellent enantioselectivities.

A new highly selective fluorescent turn-on chemosensor for cyanide anion.

A new simple molecule, 2-((2-phenyl-2H-1,2,3-triazol-4-yl)methylene)malononitrile (M1), was synthesized successfully by the Knoevenagel condensation reaction between 2-phenyl-1,2,3-triazole-4-carboxaldehyde and malononitrile. The receptor M1 is highly sensitive and selective to cyanide anion due to the nucleophilic addition of cyanide anion with M1. Distinct changes on UV-vis and fluorescence spectra can be detected with the addition of cyanide anion to the DMSO solution of M1. Optical properties of M1 were scarcely affected by the addition of other common background anions (F(-), Cl(-), Br(-), I(-), SCN(-), OH(-), CO4(2-), H2PO4(-), SO4(2-), HSO4(-), AcO(-), and NO3(-)) under the same condition. The detection limit of CN(-) reaches ~1.43 µM by M1 and the presence of background anions brought very slight interference for the detection of CN(-).

Catalytic asymmetric synthesis of quaternary α-hydroxy trifluoromethyl phosphonate via chiral aluminum(III) catalyzed hydrophosphonylation of trifluoromethyl ketones.

The chiral hydrogenated tridentate Schiff base-aluminum(III) complex has been first applied in the catalytic enantioselective hydrophosphonylation of trifluoromethyl ketones. The side reactions related to phospha-Brook rearrangement were completely avoided, and the corresponding quaternary α-hydroxy trifluoromethyl phosphonates have been first synthesized in good yields with high enantioselectivities (up to 90% ee).