Fig. 5. Effect of sikokianin C on the viability of HT29 cells with or without siRNA-mediated knockdown of CBS. (A) The IC₅₀ value of sikokianin C against HT29 cells was determined using the CCK-8 assay. (B) The IC₅₀ value of sikokianin C against HT29 cells after the siRNA-mediated knockdown of CBS was determined using the CCK-8 assay. The data represent the cell viability of the experimental group compared with that of the control group (no sikokianin C) and are presented as the means ± SD (n = 4). GraphPad Prism 6 software was used to fit the data.