New steroidal saponins from Agave angustifolia

Extraction of the dried leaves of Agave angustifolia with aqueous methanol gave a crude material that was purified by Diaion HP-20 and silica gel column chromatography to yield 1 and 2. The structure of 1 was proposed by positive ion FABMS, 1D and 2D NMR techniques and acid hydrolysis as a steroidal saponin with new pentasaccharide chain. The structure of the aglycone bearing 27 carbons was determined 25R 5 α spirostan-12 -one 3 β -ol 3 -O [β– D- xylopyranosyl (1–>4) β -D- galactopyranosyl (1–>3) {β -D- xylopyranosyl (1–>3) β -D- glucopyranosyl (1–>2)}β -D- glucopyranoside]Acid hydrolysis as well as1H and 13C NMR data of 1 revealed the presence of five monosaccharide units, two β -D- glucopyranose, one β -D- galactopyranose and two β -D-xylopyranose assigned by 1H- 1H COSY, HMQC and HMBC spectra. Compound 2 showed similar NMR signals except the absence of those due to the terminal β -D- xylopyranose attached to the outer β-D- glucopyranose, it was characterized as Cpd 2: 25R 5 α spirostan-12 -one 3 β -ol 3 -O [β -D- xylofuranosyl (1–>4) β -D- galactopyranosyl (1–>3) {β -D- glucopyranosyl (1–>2)}β -D- glucopyranoside] Further two known saponins were isolated from Agave angustifolia. The methanol extract and the saponin fraction of this plant proved to exhibit marked anti-inflammatory, analgesic, schistosomicidal, cercaricidal & miracidicidal activities.