Figure 2.

HPLC check of compound 2 in the plant ^a

^a HPLC conditions: column: LiChrospher 100 RP-18e (125 x 4 mm, 5 μm), mobile phase: 22% acetonitrile aqueous, flow rate: l mL/min, detection: 220 nm; A peak at t_R14.8 min of the chromatogram of the crude extracts bears the same UV/DAD absorption and retention time as the reference compound; The proportion of peeks at 13.0 and 14.8 min is reversal when mixing reference with crude extracts.