Antioxidative bioavailability of artepillin C in Brazilian propolis

Propolis has strong antioxidative activity. We investigated here whether this activity was available in intestinal Caco-2 and hepatic HepG2 cells. Phenolics in Brazilian propolis, extracted with ethyl acetate after the removal of resin and wax with 90% methanol, included artepillin C at 21 mmol/100 g, p-coumaric acid and cinnamic acid relatives 24 mmol, kaempferol and its derivatives 9.4 mmol, naringenin 2.8 mmol, isosakuranetin 0.9 mmol, chrysin at 0.8 mmol/100 g, and several minor components. When the extract was added to the apical side of Caco-2 monolayers, artepillin C was specifically incorporated into the cells and released to the basolateral side mostly without conjugation. Then, artepillin C was added to HepG2 cells and exposed to reactive oxygens. Artepillin C prevented oxidative damage dose-dependently, and suppressed lipid peroxidation evaluated with thiobarbituric acid reactive substances by 16% and the formation of 8-hydroxy-2′-deoxyguanosine in DNA by 36% at a concentration of 20 μM. Artepillin C is a bioavailable antioxidant.