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

Abstract

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.