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  • Molecular-level changes induced by hydroxycinnamic acid derivatives in HepG2 cell line: comparison with pravastatin
    Publication . RESSAISSI, Asma; Pacheco, Rita; Serralheiro, Maria Luisa
    Hydroxycinnamic acid derivatives are an important class of polyphenols found in fruits, vegetables, and medicinal plants and widely consumed in human diet. In the present work, alterations of HepG2 cells biochemical profile under the effect of four hydroxycinnamic acid derivatives (caffeic acid, m-coumaric acid, chlorogenic acid and rosmarinic acid) relatively to the effect of pravastatin, a drug often prescribed to inhibit HMG-CoA reductase enzyme, the regulator enzyme in the cholesterol biosynthesis pathway, were reported. The application of FTIR spectroscopy in combination with multivariate analysis by PCA showed a similarity between pravastatin and the four hydroxycinnamic acid derivatives in metabolite profile modification expressed by various changes in proteins region, the phosphate region which mainly corresponds to nucleic acids as well as in lipids regions. FTIR structural analysis in the amide I region, using resolution enhancement methods, such as second derivative and amide I deconvolution method, revealed significant decrease in alpha-helix/random coil and intermolecular beta-sheet decreased while intramolecular beta-sheet in treated cells showed an increase. It was also noticed that the intracellular cholesterol as well as esterified ingredients such as cholesterol esters in the cell membrane decreased. Moreover, principal component analysis (PCA) of the spectral data showed that the compounds and pravastatin were well separated from untreated cells showing a different mode of action on HepG2 treated cells for each compound.
  • Cholesterol transporter proteins in HepG2 cells can be modulated by phenolic compounds present in Opuntia ficus-indica aqueous solutions
    Publication . RESSAISSI, Asma; ATTIA, Nebil; Pacheco, Rita; Fale, Pedro; Serralheiro, Maria Luisa
    Increased blood cholesterol is a risk factor for atherosclerotic cardiovascular disease. This study tested the hypothesis that phenolic compounds can modulate the level of cholesterol transporters including Niemann-Pick C1-like 1 (NPC1L1) and ATP-binding cassette transporters in liver cells. HepG2 cells, used as a model of hepatocytes, showed a decrease in the abundance of cholesterol transporters comparatively to the control when treated with the Opuntia ficus-indica's cladodes decoction. The decrease was between 13-70%, 25-60%, 9-60% and 23-60% for NPC1L1, ABCA1, ABCG5 and ABCG8 transporters, respectively, when using between 0.15 and 0.35 mg/mL of decoction in the culture medium. FTIR analysis showed changes in the amount of RNA, which may be the cause of the decrease in the level of several proteins. These in vitro results pave the way to a molecular explanation for the decoction of cladodes effect on cholesterol levels as it reduced the membrane cholesterol transporter proteins, NPC1L1, ABCG5/ABCG8 and ABCA1, in HepG2 cells.