Simultaneous quantification of seven bioactive components in Caulis Lonicerae Japonicae by high performance liquid chromatography

This study presents a new HPLC method for the simultaneous determination of seven major components, namely chlorogenic acid, caffeic acid, loganin, sweroside, secoxyloganin, rutin and luteolin 7-O-glucoside in Caulis Lonicerae Japonicae, a commonly used traditional Chinese medicinal herb derived from the caulis of Lonicera japonica Thunb. These seven compounds, belonging to the chemical types of phenolic acids, iridoids and flavonoids, were separated on a C18 column (250 x 4.6 mm, 5.0 microm) with the column temperature at 30 degrees C. The mobile phase was composed of (A) aqueous acetic acid (0.4%, v/v) and (B) acetonitrile using a gradient elution of 10% B at 0-12 min, 10-17% B at 12-25 min and 17% B at 25-35 min. The flow rate was 1.0 mL/min and detection wavelength was set at 245 nm. The limit of detection (S/N = 3) ranged from 0.10 to 0.23 microg/mL and the limit of quantification (S/N = 10) ranged from 0.69 to 3.56 microg/mL. All calibration curves showed good linear regression (r2 > 0.9990) within the test ranges. The intra- and inter-day precisions as determined from sample solutions were below 1.24 and 2.28%, respectively. The recoveries for seven compounds were found to range from 94.2 to 103.6%. This verified method has been successfully applied to evaluation of commercial samples of Caulis Lonicerae Japonicae from different markets in China.