Fast determination of five components of coumarin, alkaloids and bibenzyls in Dendrobium spp. using pressurized liquid extraction and ultra-performance liquid chromatography.

A fast method for simultaneous determination of five compounds (one coumarin, two alkaloids and two bibenzyls) in Dendrobium spp. using pressurized liquid extraction and ultra-performance liquid chromatography coupled with photo diode array detection was developed. The separation was performed on an Acquity UPLC BEH C(18) column (50 mm x 2.1 mm id, 1.7 microm) with gradient elution of phosphate buffer (pH=7.1, 20 mM) and acetonitrile within 6 min. The method was validated for linearity, LOD and LOQ, precision and accuracy. All calibration curves showed good linearity (R(2) > or = 0.9999) within test ranges. The overall intra- and inter-day variations (RSDs) of five analytes were less than 2.5%, and the detection recoveries were between 95.6 and 102.3%. The developed method was successfully applied to quantitative analysis of five investigated compounds in different species of Dendrobium. The results showed that there were great variations of their contents, though all these materials were officially used as Chinese herb, Shihu. In addition, the chromatographic fingerprints of Dendrobium spp. were also investigated.