Abstract Rhizoma Polygoni Cuspidati is the rhizome of Polygonum cuspidatum Sieb. et. Zucc. (Huzhang in Chinese) which is a famous Chinese traditional medicinal herb. Historically, the plant has been widely used for expel wind and dampness, dredge the meridians and relieve pain, eliminating phlegm and alleviating cough in China. Various classes of compounds including anthraquinones, stilbenes, flavonoids, and other phenols have been isolated from this plant. Resveratrol, one of its active compounds, has been reported to have significant effect on the treatment of cardiovascular diseases through promoting cardiac protection, vasorelaxation, antioxidant activity and removing blood stasis. However, the mechanism underlying Rhizoma Polygoni Cuspidati contributes to the beneficial effect in cardiovascular diseases is not clear yet. During heart injury, the cardiac stem cells are believed to place an important role in myocardial repair. The participation of these cardiac stem cells in myocardial performance recovery is accompanied by a complex process upon potential cells recruitment, homing, growth and differentiation. In this thesis, ethanol extract of Rhizoma Polygoni Cuspidati (HZE) and resveratrol (one of the active compound in Rhizoma Polygoni Cuspidati) were found to significantly affect the proliferation and differentiation of an embryonic cardiomyoblast cell line, H9c2. The HPLC analysis showed that HZE contains high concentration of resveratrol. In vitro study showed that HZE and resveratrol inhibit cardiomyoblast proliferation without causing cells injury. Treatment with HZE and resveratrol up to 5 days induced morphological changes in the cardiomyoblast which exhibits elongation and “branching" phenotype under microscope observation. In order to understand the mechanism underlying the morphological change, we further studied the effect of resveratrol on the cellular proliferation and differentiation by cell cycle and gene expression analysis. Result of cell cycle analysis suggested that resveratrol caused G1 phase arrest dose-dependently within 9 hours of incubation. Proliferation and differentiation of H9c2 cells were further revealed by measurement of the mRNA expression of a cell cycle marker (CDK2), a differentiation marker (myogenin), and a contractile apparatus protein (MLC-2). Gene expression analysis revealed that resveratrol promoted start of cell cycle arrest but extended the myogenic differentiation progress. This finding suggests that the effect of resveratrol on cardiac differentiation may contribute to its beneficial cardioprotective effects. Keywords: Rhizoma Polygoni Cuspidati; Resveratrol; cardiomyoblast; differentiation

摘要 虎杖爲蓼科植物虎杖Polygonunt cuspidaturn Sieb.et Zuca. 的乾燥根和根莖。虎杖具有祛風利濕、散瘀定痛、止咳化痰等功效，用於關節痺痛、濕熱黄疽、閉經、定痛、咳嗽痰多、水火燙傷、跌撲損傷、臃腫瘡毒等症状。虎杖複雜的活性藥理成分，具有廣泛的藥理學作用。其中，研究主要集中在蒽醌及蒽醌甙類，芪頪及黄酮類化合物等。白藜蘆醇是虎杖中其中一種主要的有效成份，它對心血管疾病方面的防治已有廣泛報道，具有心肌損傷保護、擴張血管、擴氧化以及抗粥樣硬化等廣泛的作用。據報道指出，原始的心臟幹細胞(cardiac stem cells, CSCs)對心肌損傷的修復起著重要作用，修愎的機制可能是通過對這些原始的心肌幹細胞的調動、增殖及分化的調控來達到恢愎損傷心肌功能的效果。本論文研究發現，虎杖醇提物(HZE)及白藜蘆醇能顯著調控大鼠胎心細胞株-H9c2的增殖及分化，HPLC分析顯示HZE中含有較多的白藜蘆醇；體外細胞實驗發現，HZE及白藜蘆醇明顯抑制H9c2細胞株的增殖並且沒有造成細胞損傷，同時，經過5天的培後，加有HZE及白藜蘆醇的細胞組形態發生明顯改變，這些暗示HZE及白藜蘆醇具有調控H9c2細胞株分化的作用。為了深入解其中的作用機理，實験進一步研究白藜蘆醇對H9c2細胞株的細胞週期調控及相關基因的表達。細胞週期分析發現白藜蘆醇在9小时内引起細胞G1期停滯，基因表達結果顯示白藜蘆醇促進細胞週期停滯但延長肌樣分化過程。這發現爲研究白藜蘆醇對分化作用的研究提供理論依據。 關鍵詞:虎杖;白藜蘆醇;心肌細胞;分化