化合物strebloside是药用植物鹊肾树中的主要活性成分（强心苷类）之一。研究结果显示该化合物具有较好的肿瘤预防和抑制双重作用，其通过抑制Na/K ATP酶活性是发挥双重作用的机制之一。同时实验结果显示strebloside可促使Epstein-Barr病毒（EB）早期抗原（EA）表达的下调，从而提示Na/K ATP酶信号通路中Src酶及下游EGFR蛋白对EA的影响可能是肿瘤预防的关键。目前有关强心苷通过影响Na/K ATP酶信号通路中蛋白异常表达来阻断EB病毒对细胞损伤的机制研究国内外未见报道。本项目旨在运用Real-time PCR、Western blot、免疫荧光染色等分子生物学方法，通过对Na/K ATP酶信号通路中的关键因子表达水平的研究，明确强心苷在调节Src酶、EGFR蛋白及EA抗原的作用，以阐明强心苷在肿瘤预防和抑制双重作用的新机制。

Strebloside belongs to one of main active components (Cardiac glycoside) from medicinal plant Streblus asper. The research result suggested that strebloside exhibited high double function of tumor preventive and inhibitory activities, maybe the inhibition of Na/K ATPase is one of action mechanisms of double function. Meanwhile, the studies have found that strebloside down-regulated the expression of Epstein-Barr virus early antigen, thus providing that exhibition of the Src and EGFR effect to EA could be critical factor in Na/K ATPase signaling pathway. Up to now, there no report about the mechanism of cell injury with EB virus was induced by the protein abnormal expression of Na/K ATP signal pathway during which treated with cardiac glycosides, we will expound the effect of cardiac glycosides to Src, EGFR, and EA expressions using molecular biological methods such as Real-time PCR, western blot, and immunofluorescence staining for elucidating the mechanism of double function of tumor preventive and inhibitory activities.