Chemical structure and biological activity of steroidal saponins from Furcraea gigantea

Flavonol Glycosides and Cytotoxic Steroidal Saponins from Furcraea Tuberosa (Agavaceae)

Phytochemical analysis of the mature fruits of Furcraea tuberosa (Agavaceae) resulted in the isolation of a new bisdesmosidic spirostanol saponin (1), along with eight known steroidal glycosides (2–9), one known phenolic carboxylic acid ester (10) and three known flavonol glycosides (11–13). The structures of these compounds were assigned using a combination of 1D and 2D NMR techniques including 1H, 13C, COSY, TOCSY, HSQC and HMBC NMR, and confirmed by mass spectrometry. Thus the new saponin was elucidated as (25 R)–6α-(β-D-glucopyranosyloxy)-5α-spirostane-3β- O-[(6- O-hexadecanoyl)-β-D-glucopyranoside]. The literature survey revealed that most of the steroidal saponins isolated have shown potent cytotoxic effects against various human cancer cell lines and the results are herein reviewed.

Bioactive steroidal saponins from Agave offoyana flowers

Bioguided studies of flowers of Agave offoyana allowed the isolation of five steroidal saponins never described previously, Magueyosides A-E (1-5), along with six known steroidal saponins (6-11). The structures of compounds were determined as (25R)-spirost-5-en-2α,3β-diol-12-one 3-O-{β-d-xylopyranosyl-(1→3)-O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (1), (25R)-spirost-5-en-2α,3β-diol-12-one 3-O-{β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (2), (25R)-spirost-5-en-2α,3β,12β-triol 3-O-{β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (3), (25R)-5α-spirostan-2α,3β-diol-12-one 3-O-{β-d-xylopyranosyl-(1→3)-O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (4), and (25R)-5α-spirostan-2α,3β-diol-9(11)-en-12-one 3-O-{β-d-xylopyranosyl-(1→3)-O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranoside} (5), by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The bioactivities of the isolated compounds on the standard target species Lactuca sativa were evaluated. A dose-dependent phytotoxicity and low dose stimulation were observed.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for the period 2005-2006

This review is the fourth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2006. The review covers fundamental studies, fragmentation of carbohydrate ions, method developments, and applications of the technique to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N- and O-linked glycans from glycoproteins, glycated proteins, glycolipids from bacteria, glycosides, and various other natural products. There is a short section on the use of MALDI-TOF mass spectrometry for the study of enzymes involved in glycan processing, a section on industrial processes, particularly the development of biopharmaceuticals and a section on the use of MALDI-MS to monitor products of chemical synthesis of carbohydrates. Large carbohydrate-protein complexes and glycodendrimers are highlighted in this final section.