Asian Journal of Medicine and Health

Protective effects of three triterpenoid acids, asiatic acid (AA), glycyrrhizic acid (GA) or oleanolic acid (OA), for BEAS-2B cells, human bronchial epithelial cells, against hydrogen peroxide (H₂O₂) induced injury were examined. Cells were pre-treated with AA, GA or OA at 4 or 8 μmol/l for 48 hr at 37°C, and followed by 100 mM H₂O₂ treatment for 4 hr at 37°C. Cell viability, mitochondrial membrane potential, oxidative, apoptotic and inflammatory factors were measured. Western blot analysis was used to determine protein expression. Results showed that H₂O₂ treatment reduced both Na⁺-K⁺-ATPase activity and mitochondrial membrane potential of BEAS-2B cells. Pre-treatments from triterpenoid acids maintained Na⁺-K⁺-ATPase activity and mitochondrial membrane potential. H₂O₂ stimulated the formation of reactive oxygen species, interleukin-6, tumor necrosis factor-a and prostaglandin E₂ in BEAS-2B cells. Three triterpenoid acids pre-treatments lowered the levels of these factors. H₂O₂ enhanced the protein expression of p47^phox, gp91^phox, nuclear factor-kB (NF-kB) and p-p38. AA, GA or OA pre-treatments suppressed the expression of p47^phox, NF-kB p65 and p-p38; but only at 8 μmol/l decreased gp91^phox expression. These findings suggest that these triterpenoid acids are potent protective agents for bronchial epithelial cells to mitigate oxidative and inflammatory injury.