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From an ethanolic extract of the influorescence of Yucca aloifolia a new spirostanol glycoside has been isolated and characterized as 3-O[(alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1----2))(beta- D-glucopyranosyl(1----3)-beta-D-glucopyranosyl(1----3)-beta-D-glucopy ranosyl]-25R,5 alpha-spirostan-2 alpha, 3 beta-diol.
A new phenylpropanoid ester of a pyrroline derivative and two new steroidal saponins were isolated from the fresh bulbs of Lilium martagon, along with several previously known compounds. The structures of the new compounds were determined by spectroscopic data, hydrolysis, and by comparison with spectral data of known compounds to be (-)-5-hydroxy-3-methyl-3-pyrrolin-2-one 5-O-(6-O-p-coumaroyl-beta-D- glucopyranoside), (25S)-spirost-5-ene-3 beta,17 alpha, 27-triol 3-O-[O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl- (1-->4)-beta-D-glucopyranoside] and (25S)-5 alpha-spirostane-3 beta,17 alpha,27-triol 3-O-[O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->4)-bet a-D- glucopyranoside], respectively. Lilium martagon crosses well with L. hansonii to produce a valuable garden hybrid lily. In this study, the secondary metabolites of L. martagon were revealed to be closely related to those of L. hansonii, giving a good example of the correlation between the secondary metabolites and cross-compatibility.
Spectroscopic examination of purified extracts of the rumen content of sheep intoxicated by Brachiaria decumbens revealed the presence of two spirostanes, identified as epi-sarsasapogenin and epi-smilagenin. Sarsasapogenone was obtained by the oxidation of sarsasapogenin. The reduction of sarsasapogenone using lithium aluminum hydride yielded isomeric products, sarsasapogenin (20%) and epi-sarsasapogenin (80%).
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.
From the leaves of Agave lecheguilla Torrey, two steroidal sapogenin diols have been isolated. Mass spectral, infra-red and nuclear magnetic resonance data of these two compounds showed them to be (25R)-spirost-5-ene-2 alpha, 3 beta-diol (yuccagenin) and (25R)-5 beta-spirostane-3 beta, 6 alpha-diol. The latter is a new compound to which the trivial name ruizgenin has been given.
Although the mechanism by which dietary cholesterol is absorbed from the intestine is poorly understood, it is generally accepted that cholesterol is absorbed from bile acid micelles in the jejunum. Once inside the enterocytes, cholesterol is esterified by the action of acyl-coenzyme A:cholesterol acyltransferase (ACAT), assembled into chylomicrons, and secreted into the lymph. In this work, mechanistic aspects of cholesterol absorption were probed using compounds that block cholesterol absorption in hamsters. Sterol glycoside cholesterol absorption inhibitors, exemplified by L-166,143, (3 beta, 5 alpha,25R)-3-[(4", 6"-bis[2-fluoro-phenylcarbamoyl]-B-D-cellobiosyl)oxy]-spirostan -11-on e, potently blocked absorption of radioactive cholesterol, and the potencies of several analogs correlated with their ability to lower plasma cholesterol. Each molecule of L-166,143 blocked the uptake of 500 molecules of cholesterol, rendering it unlikely that the inhibitor interacts directly with the cholesterol or bile acid. Radiolabeled L-166,143 bound to the mucosa and binding was blocked by active, but not inactive, cholesterol absorption inhibitors. Subtle changes in the structure of sterol glycosides yielded large changes in their ability to block both cholesterol absorption and binding of radiolabeled L-166,143. Large species-to-species variation in potency was also observed. These lines of evidence support the interpretation that dietary cholesterol is absorbed via a specific transporter found in the intestinal mucosa.
A new bisdesmosidic spirostanol saponin, along with three known saponins, were isolated from Agave americana (Agavaceae). The structure of the new saponin was elucidated as (25R)-3 beta,6 alpha-dihydroxy-5 alpha-spirostan-12-one 3,6-di-O-beta-D-glucopyranoside. Among the isolated saponins, hecogenin tetraglycoside showed cytotoxic activity against HL-60 human promyelocytic leukemia cells with an IC50 value of 4.3 micrograms/mL.
Three new steroidal saponins were isolated from the fruits of Tribulus terrestris, and their structures were elucidated as (25R,S)-5 alpha-spirostane-12-one-3 beta-ol-3-O-beta-xylopyranosyl(1-->2)- [beta-xylopyranosyl(1-->3)]-beta-glucopyranosyl(1-->4)-[alpha-rhamno- pyranosyl(1-->2)]-beta-galactopyranoside; 26-O-beta-glucopyranosyl-(25S)-5 alpha-furostane-12-one-3 beta,22 alpha,26-triol-3-O-beta-glucopyranosyl(1-->2)-beta-galactopyranoside; 26-O-beta-glucopyranosyl-(25S)-5 alpha-furostane-12-one-3 beta,22 alpha,26-triol-3-O-beta-glucopyranosyl(1-->4)-[alpha- rhamnopyranosyl(1-->2)]-beta-galactopyranoside, respectively, by spectroscopic analysis and color reaction.
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.
Chemical examination of the underground parts of Tupistra chinensis led to the isolation of two new 5beta-spirostane type steroidal sapogenins, tupichigenin B (1) and C (2), together with two known steroidal sapogenins, ranmogenin A (3) and delta25(27)-pentrogenin (4). The structures of 1 and 2 were established as spirost-25(27)-ene-1beta,3beta,4beta,5beta,6b eta-pentaol and 1beta,2beta,3beta,4beta,5beta-pentahydroxyspi rost-25(27)-en-6-one, respectively, on the basis of detailed analysis of their physical and spectral data.
It is shown that 6-ketoderivatives of natural sapogenins, viz. agigenin, diosgenin and alliogenin, display the anabolic activity and do not manifest any androgenic properties. The compoud IV/(25 R)-5alpha-spirostan-2alpha, 3beta, 5alpha-triol-6-OH/produces an accelerated gain of weight in rats, and also an increase in the weight of the liver, heart, kidneys, musculus tibiliasis anterior and augments the total amount of protein therein. All of the above-mentioned changes become more pronounced with the study substance introduced to young animals. Castration of sexually immature rats greatly mitigates the anabolic effect of the compound IV.
252Cf Plasma desorption with time-of-flight mass spectrometry (TOF-PDMS) has been applied to comparative studies of the interactions of steroid glycosides (SGs) of the spirostan series with amino acids. SGs can interact with amino acids to form heteroclusters of the type [SG + aminoacid + H](+) and [SG + aminoacid + K](+). It is shown how the affinity of SGs for amino acids depends on the structures of both the SG carbohydrate chain and the SG aglycone, and on the nature of the amino acid side chain. Copyright 2000 John Wiley & Sons, Ltd.
Steroidal glycosides of the spirostane and furostane series have been isolated from the methanolic extract of Nicotiana tabacum L. seeds by using gel filtration on silica gel and chromatography on a silica gel column. They were tentatively named nicotianosides A (1), B (2), C (3), D (4), E (5), F (6), and G (7). It has been shown that nicotianosides A (1), B (2), C (3), and D (4) are 3-O-beta-D-glucopyranoside-; 3-O-alpha-L-rhamnopyranosyl (1-->2)-O-beta-D-glucopyranoside-; 3-O-¿[alpha-L-rhamnopyranosyl (1-->2)].[alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside¿: 3-O-¿[alpha-L-rhamnopyranosyl (1-->2)-alpha-L-rhamnopyranosyl (1-->3)]-alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside¿: neotigogenin, respectively. The structures of nicotianosides E (5), F (6), and G (7) have been established as: 3-O-alpha-L-rhamnopyranosyl (1-->2)-O-beta-D-glucopyranoside; 3-O-¿[alpha-L-rhamnopyranosyl-(1-->2)]-[alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside¿: 3-O-¿[alpha-L-rhamnopyranosyl (1-->2)-[alpha-L-rhamnopyranosyl (1-->3)]-alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside): (25S)-5-alpha-furostane-3 beta, 22 alpha, 26-triol [-26-O-beta-D-glucopyranoside]. Growth-stimulating activities, prevention of virus attacks on tobacco, and a possible mechanism of action were established for the nicotianosides.
Two new jatropham derivatives and three new steroidal saponins were isolated from the fresh bulbs of Lilium hansonii, along with previously known compounds. The structures of the new compounds were elucidated, on the basis of spectroscopic data and chemical evidence, and by comparing them with those of known compounds, as (-)-5-hydroxy-3-methyl-3-pyrrolin-2-one (jatropham) 5-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranoside, (2S*,4R*)-1-(3-methyl-2-oxo-3-pyrrolinyl)-4-methyl-5-oxo-2-pyrr olidinecarboxyli c acid, 26-O-beta-D-glucopyranosyl-(25R)-5 alpha-furostan-3 beta,22 zeta-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, (25R)-5 alpha-spirostan-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside and (25R)-spirost-5-en-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, respectively. The stereostructure of jatropham dimer, the plain structure of which was presented previously, was confirmed by X-ray crystallographic analysis. The inhibitory activity on cyclic AMP phosphodiesterase of the steroidal saponins was evaluated.
Three new minor steroidal saponins, (25R) 5 alpha-spirostan-3 beta-o1-6-one-3-O-[alpha-L-arabinopyranosyl(1-4)-beta-D- glucopyranoside, (25S) spirost-5-en-3 beta, 27-diol-3-O-[alpha-L-arabinopyranosyl (1-6)]-beta-D-glucopyranoside, and (25S) spirost-5-en-3 beta, 17 alpha, 27-triol-3-O-[alpha-L-arabinopyranosyl (1-6)]-beta-D-glaucopyranoside, were isolated from the root of Similax lebrunii, in addition to two known steroidal glycosides. Their structures were elucidated on the basis of chemical and spectral methods.
Three new steroidal saponins were isolated from the rhizomes of Smilax officinalis. The structures of these saponins were established by extensive spectral data, hydrolysis and chemical correlation as sarsasapogenin 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )-beta- D-glucopyranoside, neotigogenin 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )]-beta- D-glucopyranoside and 25S-spirostan-6 beta-ol 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )]-beta- D-glucopyranoside. Acid hydrolysis of the latter compound gave a sapogenin which has a new orientation of an hydroxyl on the steroidal skeleton. A route is proposed for the biogenesis of the latter sapogenin which is an uncommon steroidal aglycone.
A synthesis is reported of 3beta-hydroxy-5alpha-pregnan-20-one sulphate and the disulphate and 3-monosulphate of 5alpha-pregnane-3beta,20alpha-diol, labelled specifically with deuterium in high isotopic purity for metabolic studies in humans. Base-catalyzed equilibration of 3beta-hydroxy-5alpha-25R-spirostan-12-one (hemcogenin, II) with deuterium oxide, followed by removal of the 12-keto group and degradation of the sapogenin side-chain afforded 3beta-hydroxy-5alpha-[11,11-2H2]pregn-16-en-20-one (VII). Further deuterium atoms were introduced at the 3alpha and 20beta positions by reductions with sodium borodeuteride and lithium aluminum deuteride, respectively. These reactions led to 3beta-hydroxy-5alpha-[3alpha,11,11-2H3]pregnan-20-one (X; isotopic purity 87.2%) and 5alpha-[3alpha,11,11,20beta-2H4]pregnane-3beta,20alpha-diol (XIV; isotopic purity 83.9%). The 3-sulphate of the pregnanolone and the 3,20-disulphate of the pregnanediol were prepared directly form the free alcohols, while the 3-monosulphate of the pregnanediol was obtained via 5alpha-[3alpha,11,11,20beta-2H4]pregnane-3beta,20alpha-diol 20-acetate (XVII).
The southern Japan's soft coral, Sarcophyton glaucum, was found to contain several polyhydroxylates steroids. One of the minor components was isolated and its structure was established as 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate from spectral evidence and from comparison with a reference compound, 5 alpha-spirostan-1 beta, 3 beta, 5 alpha, 6 beta-tetrol, which was synthesized from ruscogenin. A mixture of 1 beta, 3 beta, 5 alpha, 6 beta-tetra hydroxy C27- and C28-sterols was also isolated.