XinShou Ouyang1, Kyoko Takahashi1, Katsuko Komatsu2, Norio Nakamura2, Masao Hattori2, Akemichi Baba3 and Junichi Azuma1,*
Departments of 1Clinical Evaluation of Medicines and Therapeutics and 3Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
2Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan
*Corresponding author. FAX: +81-6-6879-8259, E-mail: azuma@phs.osaka-u.ac.jp
Abstract: The effect of the root of Salvia miltiorrhiza (SM) on angiotensin II (Ang II)-induced hypertrophic responses was examined in cultured neonatal rat cardiac cells (cardiomyocytes and non-cardiomyocytes). The methanol eluate fraction (SM2) of the water extract and the ethyl acetate-insoluble fraction (SM3) and its soluble fraction (SM4) partitioned from the methanol extract were prepared. Treatment with SM4 (5-80 mg/ml), not SM2 and SM3, for 24 h produced dose-dependent cytotoxicity against cardiac cells relative to the reduction in viability and the morphological injury of cardiomyocytes. SM2 or SM3 in the absence of Ang II affected neither hyperplastic nor hypertrophic growth of both cell types. However, SM3 (40 mg/ml) attenuated the positive chronotropic responsiveness of cardiomyocytes to Ang II (1 nM) stimulation, whereas Ang II-induced increase in non-cardiomyocyte number was decreased only by SM2 (40 mg/ml) treatment. Furthermore, SM3 suppressed Ang II-induced enlargement of cell size by preceding Ang II-induced induction of immediate early response gene (c-jun) expression in cardiomyocytes, while SM2 decreased Ang II-induced DNA synthesis in non-cardiomyocytes. Moreover, three phenolic compounds and tanshinone IIA that differed quantitatively among three SM fractions were identified by reverse-phase high performance liquid chromatography. Thus, the present findings indicate that the root of SM is an effective inhibitor of Ang II action and has a plural effective constituent, which possess different pharmacological activities on Ang II-induced hypertrophy and hyperplasia in cultured neonatal rat cardiac cells.
Keywords: Salvia miltiorrhiza, Angiotensin II, Primary cultured cardiac cell, Hypertrophy, Hyperplasia
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