Comparative study on flavonoids from Tibetan medicinal plants Saussurea species using HPLC-DAD-ESI-MS

Three kinds of "Snowlotus" including Saussurea involucrate, Saussurea medusa and Saussurea laniceps had been prescribed as folk medicine interchangeably in Tibet and Uygur, China. To verify the feasibility of this phenomenon, a HPLC-DAD-ESI-MS method was developed in this study to determine the flavonoid compounds from three Saussurea species qualitatively and quantitatively. The LODs and LOQs ranged from 0.0263-0.1172 mu g/mL and 0.0862-0.3867 mu g/mL, respectively. The relative standard deviation (RSD x 100%) of the validation for the instrument precision was below 2.03%, while the RSD x 100% values for the method precision were below 5.73%, respectively. The recoveries ranged from 92.98-101.79%. These results further demonstrated that this method was precise and practical for determining flavonoid compounds from three Saussurea species. In this study, 14 kinds of constituents were simultaneously identified according to the ESI-MS data and previous studies. The contents of total flavonoids and eight components were determined with spectrophotometry and HPLC-DAD methods, respectively. The results demonstrated that the total flavonoids in S. involucrate had the hightest value and there were some differences in the content of eight flavonoids. For S. involucrate, a proportion of rutin, luteolin-7-O-glucoside, and hispidulin were detected. For S. laniceps, Arctiin, apigenin, and arctigenin were the major flavonoid compounds. For S. medusa, seven types of compounds were detected and arctiin presented the highest value, whereas apigenlin exhibited the lowest value. This comparative study may promote the differentiation in use of three kinds of snowlotus.