A New Hypoxia Inducible Factor-2 Inhibitory Pyrrolinone Alkaloid from Roots and Stems of Piper sarmentosum

A new trimethoxycinnamoyl-2-pyrrolinone alkaloid, langkamide (1), along with the known compounds piplartine (2) and 3,4,5-trimethoxycinnamic acid (3) were isolated from the roots and stems of the shrub Piper sarmentosum ROXB. The structures were established by spectroscopic analyses and comparison of their spectral data with values reported in the literature. The compounds were tested for their ability to modulate hypoxia inducible factor-2 (HIF-2) transcription activity and all three showed HIF-2 inhibitory activity with EC50 values of 14.0, 4.8, and 60.6 μM, respectively, for compounds 1, 2, and 3.