Simultaneous quantification of six sesquiterpene lactones and a flavonoid in the whole life stage of Inula salsoloides by high performance liquid chromatography

Sesquiterpene lactones and flavonoids are the most bioactive substances in Chinese herbal medicine Inula salsoloides. To explore the profiles of seven known constituents extracted from this plant, a high performance liquid chromatography (HPLC) method was established and validated. This validated method was successfully applied to the simultaneous characterization and quantification of seven known constituents in the whole life stage of Inula salsoloides collected in Yulin, Shaan'xi province at different times. The results show that the contents of 7 different constituents in the plant varied significantly during the growing stage. The sample collected on August 16th contained the highest amount of the 7 constituents. The total content of the 7 constituents gradually increased from 2.252 mg g(-1) to 25.740 mg g(-1) from May 26th to August 16th and then dropped slightly to 12.221 mg g(-1) on October 15th. This developed HPLC method could be used in quality control and standardization as well as developing a fingerprint of I. salsoloides. It may also allow for differentiation among Inula plants.