Capillary electrochromatography of boswellic acids in Boswellia serrata Roxb.

Capillary electrochromatography (CEC) was utilized for the analysis of major boswellic acids in the resin of Boswellia serrata (Indian olibanum). Baseline separation of six acidic triterpenes was obtained using a 100 μm ID fused silica capillary filled with 3 μm Hypersil ODS material, and a mobile phase comprising of acetonitrile and aqueous 20 mM ammonium formate solution (pH 6.5) in the ratio of 9 : 1 ( v : v ). The influence of relevant parameters (stationary phase, composition of mobile phase, voltage, temperature) was investigated and optimized, so that a separation was feasible within 20 min. This optimized system was then successfully used for the quantitative determination of boswellic acids in plant material. Due to their different absorption maxima, the standard compounds were detected either at 210 or 254 nm. The resulting data were precise (δ max = 3.3% based on peak area) and in good agreement with results obtained by HPLC analysis of the same sample (δ max = 4.1% between CE and HPLC results). The qualitative and quantitative results obtained prove that CEC can be a useful tool for the reliable, accurate, and economic analysis of natural products in biological samples.