Screening of specific anti-hepatoma components of Astragalus/Rhizoma curcumae and a preliminary study of underlying mechanisms

Objective To assess the anti-hepatoma activity of different components of Astragalus/Rhizoma curcumae, and to explore their mechanism of action on tumors. Methods The anti-hepatoma activity of different components of Astragalus/Rhizoma curcumae was assessed by in vitro and in vivo experiments. Apoptosis inducing effects of screened active components were studied by flow cytometry and TUNEL assay. The levels of interleukin (IL)-4, IL-18, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ in peripheral blood of tumor-bearing mice were detected by enzyme-linked immunosorbent assay (ELISA). The effect of anti-hepatoma components on tumor tissue was observed by HE staining, and the effect on the expression of vascular endothelial growth factor (VEGF) protein was detected by immunohistochemistry. The LSD-t test was used for comparisons between different groups. Results Compared with the model group, the tumor inhibition rates in the EH1, EH2, EH3, and EH4 groups were 47.55%, 36.12%, 29.96%, and 34.68%, respectively, and the in vitro tumor cell inhibition rates were 66.97%, 54.86%, 50.60%, and 45.75%, respectively; there was a significant difference among different groups. The early apoptotic rates of each group were 25.9%, 24.8%, 28.3%, and 28.8%, and the total apoptotic rates were 53.1%, 53.1%, 60.1%, and 59.1%, respectively. HE staining of tumor tissue showed that the cells were arranged neatly and uniformly, and there were a large number of necrotic areas. The average integrated optical density (IOD) for VEGF staining in the EH1 and EH2 groups decreased significantly, while the average IOD for TUNEL assay increased significantly. The levels of TNF-α, IL-18, IL-4, and IFN-γ in serum increased in the EH3 group, and except TNF-α, the difference was not statistically significant for other indicators. The average IOD for VEGF staining decreased significantly in the EH4 group, while the average IOD for TUNEL assay increased significantly. The levels of TNF-α, IL-18, IL-4, and IFN-γ in serum increased in the EH4 group, but the difference was not statistically significant. Conclusion Astragalus/Rhizoma curcumae has many anti-tumor components, and the mechanisms underlying the anti-tumor effects of different components are not exactly the same: EH3 and EH4 function by regulating immune function, while EH1 and EH2 act by inducing apoptosis and interfering with tumor tissue angiogenesis. The combination of the two can synergistically exert anti-tumor effects. Key words: Astragalus; Curcuma; Anti-tumor; Immune function; Apoptosis; Vascular endothelial growth factor