Simultaneous determination of four lignan compounds in Herpetospermum caudigerum by normal-phase high-performance liquid chromatography.

A normal-phase high-performance liquid chromatographic method with diode array UV detection is developed for the simultaneous quantitation of four lignan compounds in Herpetospermum caudigerum. This analysis provides a good resolution and reproducibility. Chromatography is carried out with a mobile phase of N-hexane-dichlormethane-methanol (42.5:42.5:5, v/v) at a flow rate of 1.0 mL/min. UV detection is performed at 280 nm. The calibration curve for lignans concentration is linear over the range of 2.10 to 42.0 microg/mL, 15.26 to 305.2 microg/mL, 6.15 to 123.0 microg/mL, and 6.24 to 124.8 microg/mL, respectively. The limit of quantitation and detection for compounds 1, 2, 3, and 4 is 1.31, 2.74, 2.63, and 2.17 microg/mL and 0.28, 0.25, 0.27, and 0.31 microg/mL, respectively. The validation data show that the assay is sensitive, specific, accurate, and reproducible for the simultaneous quantitation of four compounds. This rapid method is therefore appropriate to quantitate these lignans in Herpetospermum caudigerum.