Effects of aqueous and methanolic extracts of Astragalus Longistylus on growth and proliferation of human dental pulp stem cells

Increasing stem cell proliferation and preventing their aging is a prerequisite for cell-based therapy. Astragalus Longistylus has been used as a medicinal plant for centuries and is widely dispersed in Iran. In this study, the effect of aqueous and methanolic extracts of A. Longistylus on the growth and proliferation of human dental pulp stem cells was investigated by MTT, BrdU and flow cytometry over 24 and 48 h. The antioxidant activity of the extracts was also measured by DPPH method. The expression of BTG1 , CCND1 , and HTERT genes were also analyzed by RT-qPCR. The results of the DPPH test showed that the aqueous and methanolic extracts at the concentration of 1000 µg/mL had 29.39% and 82.71% antioxidant activity, respectively. Both the aqueous and methanolic significantly increased the cell proliferation and DNA synthesis after 48 h as revealed by MTT and BrdU assay results. Cell cycle analysis showed that the cells arrested in the G 1 phase upon treatment with both extracts after 24 h. However, after 48 h, the number of G 1 cells was reduced while the number of cells in G 2 /M phase approached that of the control group. Meanwhile, expression of CCND1 , TERT and BTG1 was reduced after 48 h by both extracts and increased following a 72 h treatment. Therefore, our findings demonstrate that the effect of the extracts on the cell proliferation was somewhat decreasing during 24 h and increasing after 48 h. These effects could be attributed to compounds such as flavonoids, polysaccharides, astragalosides, and calycosin.