Studies of selected plant raw materials as alternative sources of triterpenes of oleanolic and ursolic acid types

The qualitative and quantitative evaluation of triterpene aglycones of saponin fractions isolated from vegetative and generative organs of three Silphium species, Silphium perfoliatum, Silphium trifoliatum, and Silphium integrifolium, as compared to materials used in the herbal industry such as Panax quinquefolium root and Calendula officinalis flower, was performed. The analyses revealed that triterpene aglycones of saponins isolated from tested Silphium and Calendula species were oleanolic acid and ursolic acid. It was found that Panax roots contained only the aglycone of oleanolic acid within the triterpene saponin group. The leaves of Silphium harvested in May were characterized by the highest content of oleanolic acid-They contained 17.03 mg/g dry weight of the triterpenic acid, on average. The seasons before flowering and at the beginning of that stage appeared to be the most efficient periods for leaf collection in reference to triterpene aglycone contents in plant yield. Moreover, it was found that inflorescences of S. trifoliatum and S. integrifolium contained oleanolic acid in amounts of 22.05 and 17.95 mg/g dry weight respectively, whereas Calendula flowers contained 20.53 mg/g dry weight. The oleanolic acid content in Panax roots was 3.15 mg/g dry weight. Ursolic acid most abundantly occurred in S. integrifolium and S. trifoliatum at concentrations of about 14.98 mg/g dry weight in leaves harvested before flowering (June) and to 15.50 mg/g dry weight in leaves collected during flowering.