Improved universal approach to measure natural products in a variety of botanicals and supplements

Botanicals contain a great diversity of compounds that exhibit wide variation in their physicochemical properties. Although no single analytical method is available to measure all potentially active components, HPLC with charged aerosol detection is a nearly universal approach that nonselectively measures any nonvolatile and many semivolatile compounds; that is, CAD does not require that analytes be ionizable (as required for mass spectrometry) or contain a chromophore (as required for UV spectrophotometry). Presented are several HPLC/UHPLC methods with charged aerosol detection that have been improved to increase speed and sensitivity. The improved methods were evaluated for the measurement of phytochemicals extracted from a variety of botanicals including: triterpenoid glycosides from Bacopa monniera; steroidal and pregnane glycosides from Hoodia gordonii; oxypregnane glycosides from Caralluma fimbriata; steroidal lactones from Ashwagandha (Withania somnifera); flavonolignans from milk thistle (Silybum marianum); triterpene glycosides from black cohosh (Cimicifuga racemosa); and ginsenosides from ginseng (Panax ginseng). Analytes showed consistent response independent of chemical structure (typically < 10% variability between compounds corrected for gradient elution). All methods had a wide dynamic range (˜four orders of magnitude), good sensitivity (typically low ng levels of detection), and excellent reproducibility (RSDs typically < 2%) even at low detection levels. Comparative data from ELSD and UV detection will also be discussed.