The C-19 epimers of 5β,19-epoxycucurbita-6,23(E),25(26)-triene-3β,19-diol (1) and 5β,19-epoxy-25-methoxycucurbita-6,23-diene-3β,19-diol (2) along with (19R, 23E)-5β,19-epoxy-19-methoxycucurbita-6,23,25-trien-3β-ol (3), (23E)-5β,19-epoxycucurbita-6,23-diene-3β,25-diol (4), ligballinol (5), charantin (6) and momordicoside K (7) were isolated from the green fruits of Momordica charantia. The (S)-epimers of 1 and 2 are the first reports in nature. The acetyl- and butyryl-cholinesterase inhibitory activities of the isolated compounds were evaluated, and 5 showed the highest activity of these compounds against butyrylcholinesterase (IC50 = 32.20 μM) with a reversible and non-competitive inhibition mode.