A new steroidal saponin with antiinflammatory and antiulcerogenic properties from the bulbs of Allium ampeloprasum var. porrum.

A new steroidal saponin was isolated from the bulbs of Allium ampeloprasum var. porrumL. On the basis of chemical evidence, comprehensive spectroscopic analyses and comparison of known compounds, its structure was established as (3ß,5α,6ß,25R)-6-[(ß-D-glucopyranosyl)oxy]-spirostan-3-yl O-ß-D-glucopyranosyl-(1→2)-O-[ß-D-glucopyranosyl-(1→3)]-ß-D-galactopyranoside. Results of the present study indicated that the steroidal saponin showed haemolytic effects in the in vitro assays and demonstrated antiinflammatory activity and gastroprotective property using in vivo models.

A new steroidal saponin from Agave shrevei.

A new steroidal saponin was isolated from the leaves of Agave shrevei. Its structure was established as 3-[O-beta-D-glucopyranosyl-(1-->2)-O-[O-beta-D-glucopyranosyl-(1-->4)-O-[O-beta-D-glucopyranosyl-(1-->6)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranosyl)-oxy]-(3beta,5alpha,25R)-spirostane. The structural identification was performed using detailed analyses of 1H- and 13C-NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR, HMBC, and HMQC) and chemical conversions. The haemolytic activity of the steroidal saponin was evaluated using an in vitro assay.

Polyhydroxylated spirostanol saponins from the tubers of Dioscorea polygonoides.

Three new polyhydroxylated spirostanol saponins (1-3) were isolated from the tubers of Dioscorea polygonoides. The structures of these new compounds were determined on the basis of extensive spectroscopic analysis and the results of acid or enzymatic hydrolysis as (23S,24R,25S)-23,24-dihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (1), (23S,25R)-12alpha,17alpha,23-trihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (2), and (23S,25R)-14alpha,17alpha,23-trihydroxyspirost-5-en-3beta-yl O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (3), respectively.

Antimycotic spirostanol saponins from Solanum hispidum leaves and their structure-activity relationships.

A new spirostanol saponin, together with three known saponins, were isolated from the leaves of Solanum hispidum. The structure of the new saponin was elucidated as 6alpha-O-beta-D-quinovopyranosyl-(25S)-5alpha-spirostan-3beta-ol (1) on the basis of spectroscopic analysis (1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC, and HRFABMS). All of the isolated compounds showed antimycotic activity. The most active compound was 6alpha-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-quinovopyranosyl]-(25S)-5alpha-spirostan-3beta-ol (2) (MIC = 25 microg/mL against both Trichophyton mentagrophytes and T. rubrum). The structure-activity relationships of the isolated compounds and those isolated from S. chrysotrichum are discussed.

Five new steroidal saponins from Solanum chrysotrichum leaves and their antimycotic activity.

Using bioactivity-directed isolation procedures, five new spirostan saponins and two sterol glycosides have been isolated from Solanum chrysotrichum leaves. The structure of these compounds was established based upon spectroscopic measurements, especially 1D and 2D NMR data of their peracetate derivatives. These compounds showed antimycotic activity. The most active compound is 6alpha-O-beta-d-xylopyranosyl-(1-->3)-beta-d-quinovopyranosyl-(25R)-5alpha-spirostan-3beta,23alpha-ol (2) (MIC =12.5, 12.5, 100, and 200 microg/mL against Trichophyton mentagrophytes, T. rubrum, Aspergillis niger, and Candida albicans, respectively).

Isolation of steroidal sapogenins implicated in experimentally induced cholangiopathy of sheep grazing Brachiaria decumbens in Brazil.

As part of an experimental study, crystal-associated cholangiopathy was induced in 9 sheep by grazing pure pastures of Brachiaria decumbens in Brazil. One of these sheep showed characteristic lesions of photosensitization. The analysis of the B decumbens samples by acidic hydrolysis followed by TLC and infrared spectrum revealed diosgenin as the principal sapogenin present in the plant. In the rumen contents samples from the B decumbens-grazing group were identified by TLC, 1H and 13C NMR and EIMS as epismilagenin, episarsasapogenin, and a mixture of smilagenin and sarsasapogenin. In the bile samples from the B decumbens-grazing group, TLC analysis demonstrated 2 compounds similar to epismilagenin and episarsasapogenin. However, by this same method, those compounds were not observed in the rumen contents and bile from 2 sheep which served as control animals. The P chartarum spore counts remained very low during the experimental period.

A screen for inhibitors of DNA recombination: identification of two new spirostanol glycosides from Chamaedorea linearis.

Two new glycosides have been isolated from the MeOH extract of the stem wood and stem bark of an Ecuadorian plant Chamaedorea linearis, and their structures have been determined by spectroscopic means and X-ray analysis of the aglycone to be 1-O-[beta-L-fucopyranosyl-(4'-sulfate)]-25R,5 alpha-spirostane-1 beta, 3 beta-diol [1]) and 1-O-[beta-L-fucopyranosyl-(4'-sulfate)]-25R,5 alpha-spirostane-1 alpha, 3 beta-diol [2]. These compounds were identified in a screen for inhibitors of recombinational DNA repair. Cytotoxic activity was also demonstrated.