Objective This study explored the protective effect of tetramethylpyrazine on myocardial ischemia/reperfusion injury via inhibiting oxidative stress. Methods Primary cultured neonatal myocytes were applied to explore the anti-ischemia/reperfusion injury property in vitro. The survival viability of myocytes was determined by MTT; enzyme activities such as lactate dehydrogenase, creatine kinase, superoxide dismutase, malondialdehyde, and nitric oxide were analyzed with assay kits; inducible nitricoxide synthase and endothelial nitric oxide synthase expressions were determined by Westernblot. Results Tetramethylpyrazine significantly improved the beating frequencies of myocytes after oxygen-glucose deprivation/reoxygenation procedure, decreased lactate dehydrogenase, creatine kinase, and malondialdehyde levels and enhanced superoxide dismutase activity.Tetramethylpyrazine also inhibited excessive production of nitric oxide through downregulating inducible nitric oxide synthase as well as upregulating endothelial nitric oxide synthase during ischemia/reperfusion injury. Conclusion Tetramethylpyrazine could significantly improve the oxidative-stress tolerance of myocytes to keep cell membrane integrity and protect the myocardial tissue of normal physiological function via an antioxidant effect and by restoring the balance between inducible nitric oxide synthase and endothelial nitric oxide synthase, while inhibiting the generation of cytotoxic concentrations of NO.

AIM: To establish the quality standard of Agui Yangxue Tablets (Radix Angelicae sinensis, Radix Codonopsis, Rhizoma Atractylodis macrocephalae, etc.) METHODS: Radix Astragali, Radix et Rhizoma Glycyrrhizae and Radix Rehmanniae praeparata were identified by TLC. The content of ferulic acid and paeoniflorin was determined by HPLC. The HPLC condition of ferulic acid was as follows: column was Diamonsil~ TM C_ 18 (4.6 mm?200 mm,5 ?m), the mobile phase consisted of acetonitrile -0.085% phosphoric acid (22 ∶ 78), the UV detection wavelength was at 322 nm, the flow rate was 1.0 mL/min with column temperature at 35 ?C . The HPLC condition of paeoniflorin was as follows: column was Diamonsil~ TM C_ 18 (4.6 mm?200 mm,5 ?m), the mobile phase consisted of acetonitrile -0.1% phosphoric acid (15 ∶ 85), the UV detection wavelength was at 229 nm, the flow rate was 1.0 mL/min with column temperature at 25 ?C . RESULTS: The developed TLC spots were quite clear. The calibration curve of ferulic acid was linear with 0.012 9-0.154 8 ?g(r=0.999 7). The average recovery was 99.32% with RSD of 1.74% (n=9). The calibration curve of paeoniflorin was linear with 0.106 8-1.602 0 ?g(r= 0.999 9). The average recovery was 98.68% with RSD of 0.98 (n=9). CONCLUSION: The established TLC and HPLC methods are exclusive, reproducible and suitable for the quality control of Agui Yangxue Tables.