Structure of steroidal saponins from underground parts of Allium nutans L.

Four steroidal glycosides including deltoside and nolinofuroside D and two novel saponins were isolated from underground parts of Allium nutans L. On the basis of the spectral (LSIMS and NMR) analysis, the structures of the new compounds were established as 25R Delta(5)-spirostan 3beta-ol-3-O-¿alpha-L-rhamnopyranosyl(1-->2)-[beta-D-glucopyranosyl(1 -->4)]-O-beta-D-galactopyranoside¿ and 25R Delta(5)-spirostan 1beta, 3beta-diol 1-O-beta-D-galactopyranoside. On the basis of the extraction efficiency, the concentration of saponins was established to be about 4% of dry matter, which makes this species a good source of steroidal saponins for commercial use.

Saponins in alfalfa (Medicago sativa L.) root and their structural elucidation.

Twenty-four saponins have been identified in alfalfa roots, including 13 medicagenic acids, 2 zanhic acids, 4 hederagenins, 1 soyasapogenol A, 2 soyasapogenol B's, 1 soyasapogenol E, and 1 bayogenin glycoside. Ten of the identified compounds, including 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranosyl]-28-O-beta-D- glucopyranoside medicagenate, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta -D-glucopyranoside] medicagenic acid, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-beta- D-glucopyranoside medicagenate, 3-O-[beta-D-glucuronopyranosyl methyl ester]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1--> 2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-be ta-D-glucuronopyranosyl]-21-O-alpha-L-rhamnopyranoside soyasapogenol A, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)glucopy ranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl (1- ->2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)glucopy ranosyl]-28-O-¿beta-D-xylopyranosyl(1-->4)-)-[beta-D-apiofurano syl-(1 -->3)]- alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside¿ medicagenate, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyra nosyl(1-->2)-alpha-L-arabinopyranoside] zanhic acid, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-O-¿beta-D-xylopyranosyl(1-->4)-[beta-D-apiofurano side-(1-->3)]- alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside¿zanhic acid, and 3-O-[beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl]-28- O-b eta-D-glucopyranoside bayogenin, were not reported before, and their structures were established by spectral (FAB-MS and NMR) techniques. In addition, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-be ta-D-glucuronopyranoside] soyasapogenol E was identified in the roots for the first time.

Two oleanene glycosides from the aerial parts of Caltha polypetala.

Two new oleanene glycosides (1-2) possessing hederagenin as the aglycone were isolated from the methanolic extract of the aerial parts of Caltha polypetala together with four known glycosides. The saccharide portion linked to C-3 of the aglycone is made up of alpha-L-arabinopyranose, alpha-L-rhamnopyranose and galactopyranose in the new compounds; while compound 1 possesses linked to C-28 a trisaccharide moiety made up of two beta-D-glucopyranose and one alpha-L-rhamnopyranose unit, in compound 2 the 28-COOH group is free. The structures were elucidated by 1D and 2D NMR experiments including 1H-1H (DQF-COSY, 1D-TOCSY, 2D-ROESY) and 1H-13C (HSQC, HMBC) spectroscopy.

New naphthopyranone glycosides from Paepalanthus vellozioides and Paepalanthus latipes.

Three new compounds-3, 4-dihydro-10-hydroxy-7-methoxy-3-(R)-methyl-1H-3,4-dihydronaphtho- ]2, 3c]-pyran-1-one-9-O-beta-D-glucopyranoside (1), 3, 4-dihydro-10-hydroxy-7-methoxy-3-(R)-methyl-1H-3,4-dihydronaphtho- [2, 3c]-pyran-1-one-9-O-beta-D-glucopyranosyl-(1-->6)-glucopyranoside (2), and 3,4-dihydro-10-dihydroxy-7-methoxy-3-(R)-methyl-1H-3, 4-dihydronaphtho-[2,3c]-pyran-1-one-9-O-beta-D-allopyranosyl (1-->6)glucopyranoside (3)-were isolated from the leaves of Paepalanthus vellozioides and Paepalanthus latipes and characterized by spectrometric methods, mainly electrospray mass spectrometry and 1D and 2D NMR experiments. These unusual glycosylated dihydronaphthopyranones may serve as taxonomic markers of the genus Paepalanthus, since these compounds were not detected in other genera belonging to the Eriocaulaceae family.

Secondary metabolites from the roots of Astragalus trojanus.

Six novel cycloartane-type glycosides were isolated from the roots of Astragalus trojanus. Two of these, compounds 1 and 2, have (20R, 24S)-epoxy-3beta,6alpha,16beta,25-tetrahydroxycycloartane as the aglycon, while compounds 3-6 possess 3beta,6alpha,16beta,(24S), 25-pentahydroxycycloartane as the aglycon. The saccharide moieties linked to the C-3, C-6, and C-24 or C-25 positions of the aglycons in 1-6 contained either xylopyranose, glucopyranose, rhamnopyranose, or arabinopyranose units.

Laevisines A and B: two new sesquiterpene-pyridine alkaloids from maytenus laevis.

Two new sesquiterpene-pyridine alkaloids, laevisines A (1) and B (2), have been isolated from the bark of Maytenus laevis, along with seven known alkaloids (3-9). Their structures were elucidated by FABMS analysis and 1D and 2D NMR spectroscopy including DQF-COSY, HSQC, and HMBC.

Cycloartane triterpene glycosides from the roots of Astragalus brachypterus and Astragalus microcephalus.

Three new cycloartane-type triterpene glycosides, brachyosides A (1), B (3), and C (2), from the roots of Astragalus brachypterus and one new glycoside, cyclocephaloside II (4), from the roots of Astragalusmicrocephalus have been isolated together with five known saponins, astragalosides I, II, and IV, cyclocanthoside E, and cycloastragenol. The structures of the new compounds were established as 3-O-[beta-D-xylopyranosyl(1-->3)-beta-D-xylopyranosyl-6-O-beta-D-gluc opyranosyl-3beta,6alpha,16beta,24(S),25-pentahydrox ycycloartane (1), 3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-24-O-beta-D-glucop yranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxyc ycloartane (2), 20(R),24(S)-epoxy-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta , 25-tetrahydroxycycloartane (3), and 20(R), 24(S)-epoxy-3-O-(4'-O-acetyl)-beta-D-xylopyranosyl-6-O-beta-D-glucopy ranosyl-3beta,6alpha,16beta,25-tetrahydroxycycloart ane (4). For the structure elucidations, 1D- and 2D-NMR experiments and FABMS were used.

Flavonol and chalcone ester glycosides from Bidens andicola.

Five new flavonol 7-O-glycosides (1-5), having quercetin or quercetin 3-methyl ether as their aglycons, and sugar chains made up of three or four sugars, including beta-D-glucopyranose, alpha-L-rhamnopyranose, and beta-D-xylopyranose, have been isolated from the aerial parts of Bidens andicola, along with a new chalcone ester glycoside (6) and five known chalcone ester glycosides. The structures of 1-6 were elucidated using a combination of spectroscopic techniques.

Flavonoids reduce morphine withdrawal in-vitro.

The effects of quercetin, flavone, catechin and chrysin on the naloxone-precipitated withdrawal contracture of the acute morphine-dependent guinea-pig ileum have been investigated in-vitro. After 4 min in-vitro exposure to morphine a strong contracture of guinea-pig isolated ileum was observed after the addition of naloxone. All the flavonoids, injected 10 min before morphine at concentrations between 10(-7) and 10(-5) M, were capable of blocking naloxone-induced contracture after exposure to morphine in a concentration-dependent fashion.

Triterpenoid saponins from Spergularia ramosa.

Six new oleanene glycosides were isolated from the MeOH extract of the aerial parts of Spergularia ramosa. They possess gypsogenin or quillaic acid as the aglycons. The disaccharide moiety linked to C-3 of the aglycons is made up of galactose (or glucose) and glucuronic acid (or glucose); the pentasaccharide moiety linked to C-28 is made up of glucose (or galactose), xylose, rhamnose, fucose, and arabinose.

Croton ruizianus: platelet proaggregating activity of two new pregnane glycosides.

The MeOH extract of the aerial parts of Croton ruizianus afforded two new pregnane glycosides 1 and 2, together with the morphinandienone alkaloids flavinantine (3) and O-methylflavinantine (4). Their structures were elucidated by NMR experiments including 1H-1H (1D TOCSY and 2D DQF-COSY) and 1H-13C (HSQC, HMBC) spectroscopy. The proaggregating activity of the MeOH extract and the isolates were evaluated.

Isoquinoline alkaloids from Argemone mexicana reduce morphine withdrawal in guinea pig isolated ileum.

The present study examined the effect of the MeOH extract, partially purified fraction (IV), and pure compounds from Argemone mexicana L. (Papaveraceae) on the morphine withdrawal in guinea pig isolated ileum. The MeOH extract, the partially purified fraction (IV), and the pure compounds isolated from A.

The anti-HIV activity and mechanisms of action of pure compounds isolated from Rosa damascena.

Water and methanol extracts of Rosa damascena exhibited moderate anti-HIV activity. The anti-viral activities of 9 compounds isolated from the methanol extract were compared. The tetrahydroxyflavanone (kaempferol, 1), was effective in reducing the maturation of infectious progeny virus apparently due to selective inhibition of the viral protease.

Constituents of Ardisia japonica and their in vitro anti-HIV activity.

As part of our screening of anti-AIDS agents from medicinal plants, the MeOH extract of the aerial parts of Ardisia japonica was tested, and it showed moderate in vitro anti-HIV activity. Reexamination to identify the compounds responsible for the anti-HIV activity revealed several known compounds and a new triterpenoid saponin (4) whose structure elucidation was accomplished by 1H-1H correlation spectroscopy (COSY, HOHAHA, ROESY) and 1H-13C heteronuclear correlation (HETCOR) NMR experiments. All of the isolated compounds were tested and, although none of the triterpenoid saponins was active, bergenin and norbergenin showed weak anti-HIV activity.

New dammarane-type glycosides from Gynostemma pentaphyllum.

Four novel dammarane glycosides were isolated from a MeOH extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by 1D and 2D nmr experiments, including 1H-1H correlation spectroscopy (COSY, HOHAHA, NOESY) and 1H-13C heteronuclear correlation (HETCOR). The aglycone moieties are the new dammarane-type triterpenes (20S)-3 beta,20,23 xi-trihydroxydammar-24-en-21-oic acid-21,23-lactone for 1, the corresponding epimer at C-20(20R) for 2, (20S)-dammar-23-ene-3 beta-20,25,26- tetraol for 3, and (20R)-dammar-25-ene-3 beta,20,21,24 xi-tetraol for 4.

Constituents of Werneria ciliolata and their in vitro anti-HIV activity.

The aerial part of Werneria ciliolata afforded a series of new diterpenes: two ent-kaurane derivatives, a norkaurane, an ent-manoyloxide derivative, a dimeric diterpene, as well as a rare diterpene. Their structures were elucidated by spectroscopic methods, including the concerted application of 1D NMR techniques (DEPT and NOEDS) and 2D NMR techniques (1H-1H COSY and HETCOR). In addition, four known kauranes, four coumarins and 6-hydroxytremetone were isolated.

Inhibition of HIV infection by flavanoids.

Of a variety of flavanoids, the flavans were generally more effective than flavones and flavanones in selective inhibition of HIV-1, HIV-2 or SIV infection. Studies of their effects on the binding of sCD4 and antibody to gp120 indicated that the effective compounds interact irreversibly with gp120 to inactive virus infectivity and block infection.

Characterization of three new triterpenoid saponins from Ardisia japonica.

The isolation and characterization of three novel triterpene glycosides 1-3 from the medicinal plant Ardisia japonica (Myrsinaceae) are described. The compounds are characterized by a branched oligosaccharide chain, composed of four sugar units. The oligosaccharide structures were determined by 1H-1H correlation spectroscopy (COSY, HOHAHA, ROESY) and 1H-13C heteronuclear correlation (HETCOR) nmr experiments.

New sucrose derivatives from the bark of Securidaca longipedunculata.

Two new bitter principles were isolated from the bark of Securidaca longipedunculata (Polygalaceae) and identified as beta-D-(3,4-disinapoyl)fructofuranosyl-alpha-D-(6-sinapoyl)g lucopyranoside and beta-D-(3-sinapoyl)fructofuranosyl-alpha-D-(6-sinapoyl)gluco pyranoside. The structures were elucidated by a combination of 1H nmr (1D, 2D COSY, 2D HOHAHA), 13C-nmr, and fabms spectra.