H9c2 cardiomyoblast cell line was used to examine the protection of three triterpenes, asiatic acid, boswellic acid, and oleanolic acid, at 5 or 10 μM against high-glucose-induced injury. High glucose stimulated reactive oxygen species (ROS), oxidized glutathione (GSSG), interleukin-6, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1 production, as well as decreased glutathione peroxidase (GPX), glutathione reductase (GR) and catalase activities, and protein expression. However, pre-treatments of three triterpenes reserved glutathione, maintained activity and expression of GPX, GR, and catalase, as well as lowered ROS, GSSG, and inflammatory cytokines generation. High glucose reduced Na(+)-K(+)-ATPase activity, raised nuclear factor kappa (NF-κ) B and caspase-3 activities, up-regulated protein expression of NF-κB, mitogen-activated protein kinase, Bax, and cleaved caspase-3, as well as down-regulated Bcl-2 expression. Pre-treatments of three triterpenes retained Na(+)-K(+)-ATPase activity, declined NF-κB and caspase-3 activities, reserved Bcl-2 expression, as well as suppressed protein expression of NF-κB, p-p38, Bax, and cleaved caspase-3. These findings suggest that these triterpenes are potent cardiac-protective agents.