Quantification of Six Main Components in Moutan Cortex

In previous study, we found paeonol, paeoniflorin, benzoylpaeoniflorin, paeonolide, gallic acid and oxypaeoniflorin (Supplementary Figure S1) which were the predominant components in MC, and the quantitative analytical method with simultaneously quantifying the six ingredients in MC was established (Ge et al., 2019). Briefly, The HPLC analyses were performed using a LC-20A liquid chromatography system (Shimadzu Co., Japan) and samples were separated on an Ecosil C₁₈ (250 mm × 4.6 mm, 5 μM, Lubex Co., China). The eluent solvents consist of the deionized water with 0.2% formic acid (A) and acetonitrile (B) using a gradient program of 0–3 min, 90–89.2% A; 3–5 min, 89.2–88% A; 5–9 min, 88–87.8% A; 9–10 min, 87.8–87.7% A; 10–15 min, 87.7–87% A; 15–18 min, 87–85% A; 18–21 min, 85–84.2% A; 21–26 min, 84.2–26% A; 26–30 min, 26–10% A; 30–35 min, 10% A. The elution was performed with the eluent solvent at a flow rate of 1.0 ml/min, and 10 µl of sample solution was injected into the LC system for analysis. Two ultraviolet spectra were monitored for acquiring chromatograms of six components, at 230 nm for paeoniflorin and benzoylpaeoniflorin and 274 nm for gallic acid, paeonol, paeonolide and oxypaeoniflorin, respectively. In this study, the established method was applied to analyze the contents of paeonol, paeoniflorin, benzoylpaeoniflorin, paeoniflorin, gallic acid and oxypaeoniflorin of MCs to reflect its chemical properties.