Isolation and Identification of a Potent PTP1B Inhibitor, Ursolic Acid, from Carolina Jasmine (Gelsemium sempervirens (L.) J.St.-Hil.)

Extracts of Carolina jasmine (Gelsemium sempervirens (L.) J.St.-Hil.) petals were evaluated in vitro for inhibition activity against protein tyrosine phosphatase 1B (PTP1B). The principle active agent was also isolated from the extract and identified as ursolic acid (1). This is the first report of ursolic acid from G. sempervirens and of PTP1B-inhibiting activity in the genus Gelsemium.