Catalog of Infrared Absorption Spectra of Steroidal Sapogenin Acetates

Antiproliferative and anti-inflammatory polyhydroxylated spirostanol saponins from Tupistra chinensis

Tupistra chinensis is widely distributed in southwestern China and its rhizome is a famous folk medicine for the treatment of carbuncles and pharyngitis. Its chemical identity of potent antiproliferative and anti-inflammatory constituents has been carried out in this study. Twenty-three polyhydroxylated spirostanol saponins, including nine novels, were isolated and identified. The new spirostanol saponins were elucidated as spirost-25(27)-en-1β,2β,3β,4β,5β-pentol-2-O-β-D-xylopyranoside (1), spirost-25(27)- en-1β,2β,3β,4β,5β-pentol-2-O-α-L-arabinopyranoside (2), spirost-25(27)-en- 1β,3α,5β-triol (12), spirost-25(27)-en-1β,3α,4β,5β,6β-pentol (13), spirost-25(27)-en- 1β,2β,3β,5β-tetraol-5-O-β-D-glucopyranoside (16), 5β-spirost-25(27)-en-1β,3β-diol- 3-O-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranoside (17), (25R)-5β-spirostan- 1β,3β-diol-3-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (18), (25R)-5β- spirostan-1β,3β-diol-3-O-β-D-fructofuranosyl-(2 → 6)-β-D-glucopyranoside (19), 5β-spirost-25(27)-en-3β-ol-3-O-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranoside (20). The antiproliferative effects against seven human cancer cell lines and inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in a macrophage cell line RAW 264.7 were assayed for all the isolated compounds. Compounds 17, 19 and 21 exhibited potential antiproliferative activities against all of human cancer cell lines tested. Compounds 21 showed significant inhibition on NO production with IC₅₀ values of 11.5 μM. These results showed that the spirostanol saponins isolated from the dried rhizomes of T. chinensis have potent antiproliferative and anti-inflammatory activities and T. chinensis might be used as anticancer and.anti-inflammatory supplement.

NMR assignment of the absolute configuration of C-25 in furostanol steroidal saponins

The chemical shifts of the geminal proton resonances of H(2)-26 (δa and δb) are a widely used predictor of C-25 stereochemistry in furostanol steroidal saponins, being in general more resolved in 25S than 25R compounds. Unexpectedly, we found that application of this empirical rule in different solvents led to conflicting assignments of stereochemistry. An experimental survey revealed that, while the chemical shifts of H(2)-26 exhibit a dependence on C-25 configuration, it is less pronounced in methanol-d4 than pyridine-d5 solvent, and thus the general rule derived for pyridine-d5 fails when NMR spectra are acquired in methanol-d4. We propose a modified empirical method for the direct assignment of C-25 stereochemistry in furostanol saponins in methanol-d4 (Δ(ab)=0.45-0.48 ppm for 25S; Δ(ab)=0.33-0.35 ppm for 25R), and provide several detailed examples. In addition, the absolute configuration of compound 8, a steroidal saponin isolated in previous work from Ruscus colchicus, is corrected from 25R to 25S stereochemistry.

Steroidal saponins from Tacca plantaginea

Two new steroidal saponins, taccaoside C (1) and taccaoside D (3), along with one known saponin (2) have been isolated from the methanol extracts of Tacca plantaginea. Their structures have been elucidated by spectroscopic and chemical methods.

Dracaenogenins A and B, new spirostanols from the red resin of Dracaena cochinchinensis

A 12(13-->14)abeospirostanol dracaenogenin A (1) and a spirostanol dracaenogenin B (2) were isolated from Chinese dragon's blood, the red resin of Dracaena cochinchinensis (Agavaceae). Their structures were established as (14S,25R)12(13-->14)abeospirosta-5,13(18)-diene-1beta,3beta,15alpha-triol (1) and (25R) spirost-5-ene-1beta,3beta,14alpha,15alpha-tetrol (2) by means of spectroscopic analysis, especially by 2D NMR spectra, and X-ray crystallographic analysis. Dracaenogenin A (1) is the first example of a 12(13-->14)abeospirostane spirostanoid found in nature. Its biogenesis from ruscogenin (3) through namogenin (4) and 2 was tentatively proposed.

ESI-QqTOF-MS/MS and APCI-IT-MS/MS analysis of steroid saponins from the rhizomes of Dioscorea panthaica

Using high-resolution quadrupole time-of-flight mass spectrometry along with an electrospray ionization source (ESI-QqTOF-MS), accurate molecular weights of 13 steroid saponins extracted from the rhizomes of Dioscorea panthaica were acquired and the corresponding molecular formulae obtained. In order to elucidate the fragmentation pathways of steroid saponins in D. panthaica, 10 authentic samples were investigated using ESI-QqTOF-MS/MS. In addition, atmospheric pressure chemical ionization mass spectrometry combined with ion trap tandem mass spectrometry (APCI-IT-MS/MS) was used to analyze the structures of 13 steroid saponins in D. panthaica. Through the analysis of their tandem mass data, diagnostic fragment ions of the spirostanol and furostanol steroid saponins in D. panthaica were detected as m/z 271.2056 and 253.1951. In addition, four pairs of isomers were detected and the possible structures of four unknown steroid saponins in D. panthaica speculated. ESI-TOF and APCI-MS(n) have proved to be effective tools for research on fragmentation mechanism of steroid saponins and the rapid determination of native steroid saponins in extract mixture, thereby avoiding tedious derivation and separation steps.

Furostanoside from Asparagus filicinus

A new furostanoside, named aspafilioside D (1), together with the five known compounds officinalisnin-II (2), Asp-IV' (3), (+)-4'-O-methyl-nyasol (4), (+)-nyasol (5) and tormentic acid (6), have been isolated from the roots of Asparagus filicinus. The structure of 1 has been elucidated on the basis of spectral data.

Dependence of 1H NMR chemical shifts of geminal protons of glycosyloxy methylene (H2-26) on the orientation of the 27-methyl group of furostane-type steroidal saponins

An approach based on the difference (Delta(ab) = delta(a) - delta(b)) between the 1H NMR chemical shifts (delta(a), delta(b)) of the geminal protons of glycosyloxy methylene (H2-26) (Delta(ab) = <0.48 for 25R; Delta(ab) = >0.57 for 25S) is proposed for ascertaining 25R/25S orientation of the 27-methyl group of furostane-type steroidal saponins. These studies suggested the 25R-orientation of the 27-Me group for the furostanol glycosides isolated by Wu et al. from Tribulus terrestris.

Four New Steroid Constituents from the Waste Residue of Fibre Separation from Agave americana Leaves

Three new steroidal saponins, named agamenosides H-J (1-3), and a new cholestane steroid agavegenin D (4) were isolated from the waste residue of fibre separation from Agave americana leaves, together with six known steroids. Structures of the new compounds 1-4 were deduced to be (22S,23S,24R,25S)-24-[(beta-D-glucopyranosyl)oxy]-5alpha-spirostane-3beta,6alpha,23-triol 6-O-beta-D-glucopyranoside (1), (22S,23S,24R,25S)-5alpha-spirostane-3beta,23,24-triol 24-O-beta-D-glucopyranoside (2), (22S,23S,25R,26S)-23,26-epoxy-5alpha-furostane-3beta,22,26-triol 26-O-beta-D-glucopyranoside (3), and (22S,25S)-5alpha-cholestane-3beta,16beta,22,26-tetrol (4), respectively, by means of spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of hydrolytic cleavage.

Tuberoside M, a new cytotoxic spirostanol saponin from the seeds of Allium tuberosum

Tuberoside M (1), isolated from the seeds of Allium tuberosum, shows a significant inhibitory effect on the growth of the human promyelocytic leukemia cell line (HL-60) with IC50 value of 6.8 microg/ml. On the basis of spectral data and chemical reaction, its structure was established as (25S)-5beta-spirostane-1beta,3beta-diol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside.

Dependence of the 1H NMR chemical shifts of ring F resonances on the orientation of the 27-methyl group of spirostane-type steroidal sapogenins

A relationship between the 1H NMR chemical shifts of the ring F resonances and orientation of the H3-27 group has been derived for the establishment of 25R- and 25S-stereochemistry in spirostane type of steroidal sapogenins.

Solasodine glycosides of Solanum unguiculatum (A.) Rich

Besides solasonine, three new glycosides, namely, 3-O-alpha-L-rhamnopyranosyl-(1-->3)-solasodine, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->4)-beta -D- galactopyranosyl solasodine, and 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl solasodine, were isolated from Solanum unguiculatum (A.) Rich. Their structures were determined on the basis of chemical and spectral methods.

A tigogenin pentasaccharide from Cestrum diurnum

A new steroidal saponin named diurnoside 1 has been isolated from a methanolic extract of fresh leaves of Cestrum diurnum and the structure, (25 R)-5 alpha-spirostan-3beta-yl-4-O-[2-O-(beta-D-gluco pyranosyl)-beta-D-glucopyranosyl]-3-O-[beta-D-xylopyranosyl]-beta-D- glucopyranosyl]-beta-D-galactopyranoside, was determined by modern NMR technique and chemical reactions.

Steroidal saponins from the bulbs of Allium schubertii

Phytochemical examination of the fresh bulbs of Allium schubertii led to the isolation of four new steroidal saponins together with a known saponin. The structures of the new saponins were established by spectroscopic data, hydrolysis and chemical correlation as (25R and S)-5 alpha-spirostan-2 alpha,3 beta,6 beta-triol 3-O-beta-D-glucopyranosyl-(1-->2)-O-[4-O-benzoyl-beta-D-xylopyranosyl- (1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside, (25R and S)-5 alpha-spirostan-2 alpha,3 beta,6 beta-triol 3-O-beta-D-glucopyranosyl-(1-->2)-O-[3-O-benzoyl-beta-D-xylopyranosyl- (1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside, (25R and S)-5 alpha-spirostan-2 alpha,3 beta,6 beta-triol 3-O-beta-D-glucopyranosyl-(1-->2)-O-[4-O-(3S)-3-hydroxy-3-methylgluta royl- beta-D-xylopyranosyl-(1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D- galactopyranoside and 26-O-beta-D-glucopyranosyl-(25R and S)-5 alpha-furostan-2 alpha,3 beta,6 beta,22 zeta,26-pentol 3-O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O-bet a- D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside, respectively.