Bitter gourd (Momordica charantia) extract activates peroxisome proliferator-activated receptors and upregulates the expression of the acyl CoA oxidase gene in H4IIEC3 hepatoma cells.
Peroxisome proliferator-activated receptor alpha (PPARalpha) is a ligand-dependent transcription factor that regulates the expression of genes involved in lipid metabolism and transport. Ligands/activators of PPARalpha, like fibrate-type drugs, may have hypolipidemic effects. To identify food that contains activators of PPARalpha, a transactivation assay employing a clone of CHO-K1 cells stably transfected with a (UAS)(4)-tk-alkaline phosphatase reporter and a chimeric receptor of Gal4-rPPARalpha LBD was used to screen ethyl acetate (EA) extracts of a large variety of food materials. It was found that the EA extract of bitter gourd (Momordica charantia), a common oriental vegetable, activated PPARalpha to an extent that was equivalent to or even higher than 10 microM Wy-14643, a known ligand of PPARalpha. This extract also activated PPARgamma to a significant extent which was comparable to 0.5 microM BRL-49653. The activity toward PPARalpha was mainly in the soluble fraction of the organic solvent. The EA extract prepared from the whole fruit showed significantly higher activity than that from seeds or flesh alone. The bitter gourd EA extract was then incorporated into the medium for treatment of a peroxisome proliferator-responsive murine hepatoma cell line, H4IIEC3, for 72 h. Treated cells showed significantly higher activity of acyl CoA oxidase and higher expressions of mRNA of this enzyme and fatty acid-binding protein, indicating that the bitter gourd EA extract was able to act on a natural PPARalpha signaling pathway in this cell line. It is thus worth further investigating the PPAR-associated health benefits of bitter gourd.
Chao
Che-Yi
CY
Laboratory of Nutritional Biochemistry, Department of Biochemical Science and Technology, Institute of Microbiology and Biochemistry, National Taiwan University, 1 Roosevelt Road Sec. 4, Taipei 106, Taiwan, ROC.
Huang
Ching-jang
CJ
D042962:Acyl-CoA Oxidase / Q000235:genetics*; D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D051379:Mice; D029777:Momordica charantia / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects* / Q000302:isolation & purification; D015398:Signal Transduction; D014157:Transcription Factors / Q000187:drug effects* / Q000302:isolation & purification; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection
D010936:Plant Extracts; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D042962:Acyl-CoA Oxidase