Garlic inhibits microsomal triglyceride transfer protein gene expression in human liver and intestinal cell lines and in rat intestine.
Epidemiologic studies have suggested that fresh garlic has lipid-lowering activity. Because the microsomal triglyceride transfer protein (MTP) plays a pivotal role in the assembly and secretion of apolipoprotein B (apoB)-containing lipoproteins, we evaluated the effect of garlic on the expression of the MTP gene in vitro in cell lines and in vivo in rats. Fresh garlic extract (FGE) reduced MTP mRNA levels in both the human hepatoma HepG2 and intestinal carcinoma Caco-2 cells in dose-dependent fashion; significant reductions were detected with 3 g/L FGE. Maximal 72 and 59% reductions, respectively, were observed with 6 g/L FGE. To evaluate the in vivo effect of garlic on MTP gene expression, rats were given a single oral dose of fresh garlic homogenate (FGH), with hepatic and intestinal MTP mRNA measured 3 h after dosing. Rats fed FGH had significantly (46% of the control) lower intestinal MTP mRNA levels compared with the control rats, whereas hepatic MTP mRNA levels were not affected. These results suggest a new mechanism for the hypolipidemic effect of fresh garlic. Long-term dietary supplementation of fresh garlic may exert a lipid-lowering effect partly through reducing intestinal MTP gene expression, thus suppressing the assembly and secretion of chylomicrons from intestine to the blood circulation.
Lin
Marie C
MC
Institute of Molecular Biology, Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Hong Kong, China. mclin@hkusua.hku.hk
Wang
Er-Jia
EJ
Lee
Catherine
C
Chin
K T
KT
Liu
Depei
D
Chiu
Jen-Fu
JF
Kung
Hsiang-Fu
HF
D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D004305:Dose-Response Relationship, Drug; D005737:Garlic / Q000737:chemistry*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D014407:Tumor Cells, Cultured
D001055:Apolipoproteins B; D002352:Carrier Proteins; D010936:Plant Extracts; C106092:microsomal triglyceride transfer protein