Purification of toxic saponins from Narthecium asiaticum Maxim.

Toxic substances in Narthecium asiaticum Maxim. were isolated and purified, monitoring the oral toxicity in guinea pigs. The crude extract prepared from the methanolic extract of the plant contained 2 major saponins (C8 and C9), and 7 corresponding saponins (C1-7) on TLC. The crude extract was fractionated by a conventional method for saponin preparation. The 1-butanol fraction was rich in C8 and C9, and showed oral toxicity. C8 and C9 were isolated by fractional precipitation and silica gel column chromatography. On the basis of C-13 and H-1 nuclear magnetic resonance (NMR) spectral data, and acid and enzymatic hydrolysis of C9, C9 was confirmed to be a mixture of two furostanol saponins (C9a, C9b); a branched trisaccharide composed of galactose, glucose, and arabinose, was linked at 3 beta-C, and glucose at 26-C of sarsasapogenin and smilagenin. C8 was considered to be a furostanol saponin containing xylose instead of arabinose in the structure of C9. Oral administration of C8 and C9 caused diarrhea, proteinuria, hematuria and death in guinea pigs.