Preventative effects of 4,4'-diphenylmethane-bis(methyl) carbamate isolated from cortex mori on human umbilical vein endothelial cell dysfunction induced by advanced glycation end products.

Advanced glycation end-products (AGEs) have been regarded as an initial motivating factor in the pathogenesis of endothelial dysfunction in diabetic complications. 4,4'-Diphenylmethane-bis(methyl) carbamate (DMPC), a carbamate compound, was isolated from Cortex Mori and its prevention effects against AGEs-induced endothelial dysfunction were studied. 4,4'-Diphenylmethane-bis(methyl) carbamate significantly reduced cell apoptosis to normal level at 10⁻9 mol/L concentration. Advanced glycation end-products up-regulated the expression of Bad and Bax and down-regulated Bcl-2 proteins, and pretreatment with DMPC significantly down-regulated Bad and Bax while up-regulating Bcl-2 expressions. In addition, ICAM (intercellular adhesion molecule)-1 and TGF (transforming growth factor)-ß1 expressions in human umbilical vein endothelial cell (HUVEC) were significantly enhanced by AGEs. More importantly, these increases of ICAM-1 and TGF-ß1 expressions were reduced meaningfully with the pretreatment of DMPC. All the results showed DMPC had prevention effects against the progression of AGE-induced endothelial dysfunction, and this compound might be a promising agent against endothelial dysfunction in diabetic vascular complications.

Competitive binding between 4,4'-diphenylmethane-bis(methyl) carbamate and RAGE ligand MG-H1 on human umbilical vein endothelial cell by cell membrane chromatography.

The compound 4,4'-diphenylmethane-bis(methyl) carbamate (CM1) has a protective activity on AGEs-induced endothelial dysfunction on human umbilical vein endothelial cell (HUVEC) in our previous study. It suggested that CM1 which may act as a competitive antagonist to the blockade of AGEs to receptor of AGEs (RAGE) and attenuate the HUVEC damage. In order to testify that hypothesis, the cell membrane chromatography (CMC) combined with high performance liquid chromatography (HPLC) was developed for analyzing the competitive binding properties on RAGE of HUVEC between CM1 and MG-H1, the agonist of RAGE. The results from saturation binding of CM1 and MG-H1 on cells demonstrated that dissociation equilibrium constants (K(d)) of CM1 and MG-H1 were 3.653 nM and 4.12 nM, respectively; while maximum binding capacity (B(max)) of CM1 and MG-H1 were 30.08 and 18.72 fmol/mg protein, respectively. In competition experiments, IC50 of CM1 with pre-incubation 10⁻¹° M and 10⁻9 M MG-H1 were 1.37 × 10⁻9 M and 4.56 × 10⁻8 M, respectively. The present findings indicated that CM1 conjugated competitively to cells with RAGE ligand MG-H1. The primary study illustrated that CMC combined with HPLC analysis method could be an alternative, rapid and efficient approach for the interaction of drug molecule and receptor, and that CM1 intervene the AGEs inducing HUVEC damage may via the competitively block the AGEs-RAGE path way.

Oleanolic acid from Prunella Vulgaris L. induces SPC-A-1 cell line apoptosis via regulation of Bax, Bad and Bcl-2 expression.

Prunella vulgaris L. (PV) has been used as a herb for chemoprevention of lung cancer. In this study, the main active compound, oleanolic acid (OA) was isolated from an ethanol extract and its chemical structure was identified according to the results of high performance liquid chromatography (HPLC), high performance thin layer chromatography (HPTLC) and liquid chromatography-mass spectrography (LC-MS). Results for cell viability indictated no notable differences between OA and ethanol extract of PV in lung adenocarcinoma SPC-A-1 cells measured by MTT assay. Consistent concentration-response curves. Fluorescence detection with acridine orange-ethidium bromide was used to evaluate apoptosis of SPC-A-1 cells. OA at 16 and 8 microM group increased significantly the apoptosis rate compared with normal and 1% DMSO groups (p<0.05). In addition, immunocytochemistry assays showed increase in Bax and Bad protein expression while Bcl-2 decreased. Moreover, the ratio of Bax/Bcl-2 was heightened by OA treatment. The results suggest OA induced apoptosis of lung adenocarcinoma cells through down-regulating Bcl-2 expression, and up-regulating Bax and Bad expression.