Protective effects of acacetin isolated from Ziziphora clinopodioides Lam. (Xintahua) on neonatal rat cardiomyocytes

BACKGROUND The total flavonoids from ethanol extract of the aerial part of Ziziphora clinopodioides Lam. (Lamlaceae) (Xintahua) showed protective activities against rat acute myocardial ischemia in rats. This study aims to isolate acacetin, a flavonoid, from the aerial part of Z. clinopodioides, to develop an HPLC method for its detection, and to evaluate its protective effects on neonatal rat cardiomyocytes. METHODS Sephadex LH-20 silicagel and pillar layer chromatography silica gel were applied for the isolation and purification of acacetin and its structure was elucidated on the basis of (1)H and (13)C NMR spectroscopy. The content of acacetin in Z. clinopodioides collected from three different origins was determined by HPLC. The neonatal rat cardiomyocytes were isolated and cultured in vitro to establish a hypoxia/reoxygenation injury model. The viability of cardiomyocytes was measured by the MTT method. Changes of malondialdehyde (MDA) content in the medium were also determined. RESULTS The acacetin content in various batches of Z. clinopodioides ranged from 45.50 to 47.41 μg/g. Acacetin of 25, 10, 5 μg/mL significantly decreased the MDA content in a model of hypoxia/reoxygenation injury (P < 0.001, P < 0.001 and P = 0.033, respectively). CONCLUSIONS Acacetin protects neonatal cardiomyocytes from the damage induced by hypoxia/reoxygenation stress through reduction of lipid peroxidation and enhancement of the antioxidant activity.