Quality evaluation of Flos Lonicerae through a simultaneous determination of seven saponins by HPLC with ELSD

Abstract

A new HPLC coupled with evaporative light scattering detection (ELSD) method has been developed for the simultaneous quantitative determination of seven major saponins, namely macranthoidin B ( 1), macranthoidin A ( 2), dipsacoside B ( 3), hederagenin-28- O-β- d-glucopyranosyl(6→1)- O-β- d-glucopyranosyl ester ( 4), macranthoside B ( 5), macranthoside A ( 6), and hederagenin-3- O-α- l-arabinopyranosyl(2→1)- O-α- l-rhamnopyranoside ( 7) in Flos Lonicerae, a commonly used traditional Chinese medicine (TCM) herb. Simultaneous separation of these seven saponins was achieved on a C 18 analytical column. The mobile phase consisted of (A) acetonitrile–acetic acid (95:0.5) and (B) 0.5% aqueous acetic acid using a gradient elution of 29%A at 0–10 min, 29–46%A at 10–25 min and 46%A at 25–30 min. The drift tube temperature of ELSD was set at 106 °C, and with the nitrogen flow-rate of 2.6 l/min. All calibration curves showed good linear regression ( r 2 > 0.9922) within test ranges. This method showed good reproducibility for the quantification of these seven saponins in Flos Lonicerae with intra- and inter-day variations of less than 3.0% and 6.0%, respectively. The validated method was successfully applied to quantify seven saponins in five sources of Flos Lonicerae, which provides a new basis of overall assessment on quality of Flos Lonicerae.