Figure 1: Chemical standardization of AR extract by HPLC fingerprint analysis. (a) Calycosin, calycosin-7-O-β-D-glucoside, formononetin, and ononin are the major flavonoids contained within AR water extract. (b) In a HPLC fingerprint at an absorbance of 280 nm, the peaks corresponding to calycosin-7-O-β-D-glucoside (1), ononin (2), calycosin (3), and formononetin (4) were identified as standards (upper panel). The chemical amounts of these four compounds contained within the water extract of AR were calculated according to the HPLC results (lower panel). Representative chromatograms are shown; .