Novel Sesterterpenes from Leucosceptrum canum of Nepalese Origin

Two novel sesterterpenoids, leucosesterterpenone (1) and leucosesterlactone (2), with novel skeleta were isolated from the hexane extract of the medicinal plant, Leucosceptrum canum. Their structures were established by the analysis of NMR data and the single-crystal X-ray diffraction of compound 1. Compounds 1 and 2 were found to exhibit activity against prolylendopeptidase (PEP).