Figure 1.

Extracted ion chromatograms of catalposide and its possible metabolites after incubation of 200 μM catalposide with (A) human hepatocytes for 2 h at 37 °C in a CO₂ incubator and (B) human intestinal microsomes in the presence of UDPGA at 37 °C for 1 h (mass accuracy: 5 ppm). The extracted ion chromatograms were reconstructed based on the [M–H]⁻ ions: m/z 481.1349 for catalposide, m/z 561.0921 for M1 (catalposide sulfate), m/z 137.0239 for M2 (4-hydroxybenzoic acid), m/z 313.0569 for M3 (4-hydroxybenzoic acid glucuronide), and m/z 657.1674 for M4 (catalposide glucuronide).