Isolation of Betulinic Acid its Methyl Ester and Guaiane Sesquiterpenoids with Protein Tyrosine Phosphatase 1B Inhibitory Activity from the Roots of Saussurea lappa C.B.Clarke

摘要

Activity-guided fractionation of a MeOH extract of the roots of Saussurea lappa C.B.Clarke (Compositae), using an in vitro protein tyrosine phosphatase 1B (PTP1B) inhibition assay, led to the isolation of four active constituents: betulinic acid (>1), betulinic acid methyl ester (>2), mokko lactone (>3) and dehydrocostuslactone (>4), along with nine inactive compounds. Our findings indicate that betulinic acid (>1) and its methyl ester >2, as well as the two guaiane sesquiterpenoids >3 and >4 are potential lead moieties for the development of new PTP1B inhibitors.