Inhibitory effect of novel diallyldisulfide analogs on HMG-CoA reductase expression in hypercholesterolemic rats: CREB as a potential upstream target.
OBJECTIVE
Diallyldisulfide (DADS), an active principle of garlic (Allium sativum) is known for its antihyperlipidemic properties. The present study was designed to evaluate the effect of novel synthesized DADS analogs, on the lipid profile of hypercholesterolemic rats and to investigate the molecular correlates of their activity at the cellular level.


METHODS
Wistar rats, weighing 100-120 g each, were administered with 5% cholesterol for one week, and subsequently administered with lovastatin, allicin and DADS (20 mg/kg wt) analogs in the second week along with 5% cholesterol. All animals were sacrificed after overnight starvation.


RESULTS
Our results show that DADS analogs are effective in reducing the total lipid levels which could be correlated with a significant decrease in 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) activity. DADS analogs strongly inhibit HMGR activity in vivo but not in vitro. These results can be attributed to the significant decrease in the mRNA levels and protein expression of HMGR. Further, we show that DADS analogs significantly inhibited the activation of sterol regulatory element-binding protein-2 (SREBP-2) and interfered with DNA binding activity of cAMP response element-binding protein (CREB) but not nuclear factor-Y (NF-Y), with upstream regulatory sequences of HMGR. Moreover, DADS analogs are also effective in reducing the levels of oxidized low-density lipoprotein (ox-LDL), lipid peroxidation as well as NF-kappaB activity, showing good anti-inflammatory and antioxidant properties.


CONCLUSIONS
The unique anti-inflammatory effect and hypolipidemic action of DADS analogs may be beneficial in preventing the vascular complications that are induced by hyperlipidemia and provide a new therapeutic approach for the treatment of cardiovascular and related diseases.
Rai
Santosh Kumar
SK
Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India.
Sharma
Meenakshi
M
Tiwari
Manisha
M
D000498:Allyl Compounds / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D050882:CREB-Binding Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D004195:Disease Models, Animal; D004220:Disulfides / Q000494:pharmacology*; D024202:Electrophoretic Mobility Shift Assay; D005737:Garlic; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics* / Q000378:metabolism; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D006937:Hypercholesterolemia / Q000139:chemically induced / Q000201:enzymology / Q000517:prevention & control*; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008077:Lipoproteins, LDL / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051779:Sterol Regulatory Element Binding Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014280:Triglycerides / Q000097:blood
D000498:Allyl Compounds; D004220:Disulfides; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D000960:Hypolipidemic Agents; D008077:Lipoproteins, LDL; D016328:NF-kappa B; D012333:RNA, Messenger; C470194:Srebf2 protein, rat; D051779:Sterol Regulatory Element Binding Proteins; D014280:Triglycerides; C099252:oxidized low density lipoprotein; C028009:diallyl disulfide; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D050882:CREB-Binding Protein; C494365:Crebbp protein, rat