Cucurbitane-type triterpenoids from the aerial parts of Momordica charantia L.

Abstract Six new cucurbitane-type triterpenoids ( 1 – 6 ), together with two known analogues ( 7 and 8 ) were isolated from the aerial parts of Momordica charantia L. The structures of new compounds were identified as cucurbita-6,24-dien-3β,23-diol-19,5β-olide ( 1 ), (19 R )-5β,19-epoxy-19-methoxycucurbita-6,24-dien-3β,23-diol ( 2 ), (19 S )-5β,19-epoxy-19-methoxycucurbita-6,24-dien-3β,23-diol ( 3 ), (19 R )-5β,19-epoxy-19-isopropoxycucurbita-6,24-dien-3β,23-diol ( 4 ), 3β,23-dihydroxy-5-methoxycucurbita-6,24-dien-19-al ( 5 ) and (19 R )-7β,19-epoxy-19-methoxycucurbita-5,24-dien-3β,23-diol ( 6 ), by extensive MS, 1D and 2D NMR spectroscopic technologies. This is the first report of the isolation of tetracyclic triterpenoids possessing a 7β,19-epoxy system, viz., 6 , from M. charantia L.