Monoclonal antibody-directed analysis of benzo[a]pyrene metabolism in rat liver and extrahepatic tissues: effect of propyl and octyl gallate

Synthesis, crystal structure, and growth inhibition of human hepatoma cell (HepG2) of polyphenolic compounds based on gallates

Seven compounds (1–7) based on gallate were synthesized and characterized by elemental analysis, 1H NMR, and MS spectra. 2-(3,5-Dibenzyloxy-4-methoxy)phenyl-2-propanol (6) was a new compound. Methyl 3,5-dihydroxy-4-methoxybenzoate (3), methyl 3,5-dibenzyloxy-4-methoxybenzoate (4), 3,5-dibenzyloxy-4-methoxybenzyl alcohol (5), and compound 6 were structurally determined by single-crystal X-ray diffraction for the first time. Crystallographic data for 3: space group P212121; a = 4.0750(8) Å, b = 7.5880(15) Å, c = 29.802(6) Å; V = 921.5(3) Å3; Z = 4. 4: space group P-1; a = 10.068(2) Å, b = 10.499(2) Å, c = 11.388(2) Å; α = 76.84(3)°, β = 66.79(3)°, γ = 64.10(3)°; V = 993.0(3) Å3, Z = 2. 5: space group P-1; a = 8.1410(16) Å, b = 8.7590(18) Å, c = 12.879(3) Å; α = 91.66(3)°, β = 94.69(3)°, γ = 91.73(3)°; V = 914.4(3) Å3; Z = 2. 6: space group P21/c; a = 5.8100(12) Å, b = 15.778(3) Å, c = 23.237(5) Å; β = 96.09(3)°; V = 2118.1(7) Å3; Z = 4. All of the seven compounds were evaluated for the inhibition of growth of human hepatoma (HepG2) cells. Comparison with the positive-control 5-fluorouracil (IC50 51.6 µmol/L), 5 showed stronger cytotoxic activity with an IC50 around 15.3 µmol/L, while IC50 value of 3 was 90.3 µmol/L. The effect of slight structural variations in this series of compounds was found to cause a marked change in their activity against HepG2 cells.Key words: gallates, benzyl alcohol, human hepatoma cells, crystal structure, anti-cancer activities.

Selective immunoclean-up followed by liquid chromatography for the monitoring of a biomarker of exposure to polycyclic aromatic hydrocarbons in urine at the ngl−1 level

A selective clean-up procedure using an immunosorbent (IS) was developed for the trace-level determination, in water and urine samples, of 3-benzo(a)pyrene-glucuronide (3-BP-G), a biomarker of exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs). First, three sorbents used for the immobilization of antibodies were evaluated for their ability to limit the risk of non-specific interactions and to provide a high bonding density. The best sorbent, i.e. sepharose, was used for the immobilization of two different monoclonal antibodies. The most specific antibody for 3-BP-G was applied to the selective extraction from urine providing a clean extract, an easy and reliable quantification by comparison with a classical SPE process. The sensitivity of the fluorescence associated with the selectivity of the IS provides a limit of detection up to 1.2 ng l(-1) in urine for 3-BP-G.

Correlation of antimutagenic activity and suppression of CYP1A with the lipophilicity of alkyl gallates and other phenolic compounds

Alkyl gallates are widely used as food antioxidants. Methyl, ethyl, propyl, lauryl, and cetyl gallates showed antimutagenicity to activated 2-aminoanthracene (2AA)-induced SOS responses in Salmonella typhimurium TA1535/pSK1002. They also exhibited a suppressive effect on 3-methylcholanthrene (3-MC)-induced cytochrome P450 1A (CYP1A) in human hepatoma HepG2 cells, as indexed by the 7-ethoxyresorufin-O-deethylase (EROD) activity, and on CYP1A protein level. Both antimutagenicity and suppression of CYP1A appeared to be dependent on alkyl chain lengths, which suggested lipophilicity dependence. Based on those results, we investigated 26 other phenolic compounds for their lipophilicity, antimutagenicity and inhibition of EROD activity. The lipophilicity correlated well with the inhibition of EROD activity (r=0.78), and the inhibition of EROD activity correlated with the antimutagenicity of those compounds (r=0.71). The results suggest that the lipophilicity of the phenolic compounds may be an important factor in their ability to inhibit EROD activity.