Toxic substances in Narthecium asiaticum Maxim. were isolated and puri
fied, monitoring the oral toxicity in guinea pigs. The crude extract p
repared from the methanolic extract of the plant contained 2 major sap
onins (C-8 and C-9), and 7 corresponding saponins (C1-7) on TLC. The c
rude extract was fractionated by a conventional method for saponin pre
paration. The 1-butanol fraction was rich in C-8 and C-9, and showed o
ral toxicity. C-8 and C-9 were isolated by fractional precipitation an
d silica gel column chromatography. On the basis of C-13 and H-1 nucle
ar magnetic resonance (NMR) spectral data, and acid and enzymatic hydr
olysis of C-9, C-9 was comfirmed to be a mixture of two furostanol sap
onins (C-9a, C-9b); a branched trisaccharide composed of galactose, gl
ucose, and arabinose, was linked at 3beta-C, and glucose at 26-C of sa
rsasapogenin and smilagenin. C-8 was considered to be a furostanol sap
onin containing xylose instead of arabinose in the structure of C-9. O
ral administration of C-8 and C-9 caused diarrhea, proteinuria, hematu
ria and death in guinea pigs.