Constituents of Cuscuto Reflexa are anti-HIV Agents

Crude water extracts of Cuscuta reflexa exhibited anti-HIV activity. Fractionation of the crude extract led to the isolation of nine pure compounds with closely related structures, showing interesting structure activity relationships. 3,5,7,4′-Tetrahydroxyflavanone (aromadendrin) inhibited infection by binding to V3 loop of gp 120 and inhibiting its interaction with CD4, whereas 3,5,7,3′,4′-pentahydroxyflavanone (taxifolin), with an extra OH group in the 3′ position in ring B was less specific and exhibited less selectivity in cell cultures. In general, flavanones containing an extra OH group in the 3′ position (taxifolin, taxifolin-7-O-β-D-glucopyranoside and coccinoside B) were less specific and inhibited viral protease, reverse transcriptase, CD4 /gp120 interaction in vitro and bound to non specific proteins. Other compounds isolated from C reflexa were derivatives of quinic acids; 3,4-O-dicaffeoylquinic acid was more active than 3-O-caffeoyl quinic acid. The anti-HIV activity of crude extract may be the result of combinatory effects with compounds of different modes of action.

Antiproliferative and pro-apoptotic activity of novel phenolic derivatives of resveratrol

Gloriosaols A-C, isolated from Yucca gloriosa (Agavaceae), are novel phenolic compounds structurally related to resveratrol. In the present study, we show that gloriosaols possess antiproliferative and pro-apoptotic activity on tumor cells of different histogenetic origin and that their cell growth inhibition potential is higher than that of resveratrol. Despite the close similarities in their structure, gloriosaols A-C exhibited different antiproliferative potency, as the EC(50) ascending order is: gloriosaol C, gloriosaol A, gloriosaol B. Further mechanisms of gloriosaol C cytotoxicity were elucidated in detail in U937 cells, the most sensitive of the cell lines tested. The effect of gloriosaol C on cell growth turned out to be strongly dependent upon the concentration. Gloriosaol C doses lower than the EC(50) value (8 mu-icroM) blocked the cell cycle in G(0)/G(1), with a concurrent decrease in the number of cells in the G(2)/M phases of the cell cycle. At higher doses, this arrest overlaps with the occurrence of apoptosis and necrosis. In the 10-25 microM range of doses, gloriosaol C caused cell death mainly by apoptosis, as measured by hypodiploidia induction, phosphatidyl serine externalization and disruption of mitochondrial transmembrane potential. A switch in the mode of death from apoptosis to necrosis occurred at doses of gloriosaol C higher than 30 microM. Gloriosaol C was found to induce production of reactive species dose-dependently, but also to counteract their elevation in stressed cells. Thus, the different fate of cells, that is cell cycle arrest or cell death, in response to different doses of gloriosaol C might be related to the extent of induced oxidative stress.

Anti-inflammatory and anti-arthritic effects of Yucca schidigera: a review

Yucca schidigera is a medicinal plant native to Mexico. According to folk medicine, yucca extracts have anti-arthritic and anti-inflammatory effects. The plant contains several physiologically active phytochemicals. It is a rich source of steroidal saponins, and is used commercially as a saponin source. Saponins have diverse biological effects, including anti-protozoal activity. It has been postulated that saponins may have anti-arthritic properties by suppressing intestinal protozoa which may have a role in joint inflammation. Yucca is also a rich source of polyphenolics, including resveratrol and a number of other stilbenes (yuccaols A, B, C, D and E). These phenolics have anti-inflammatory activity. They are inhibitors of the nuclear transcription factor NFkappaB. NFkB stimulates synthesis of inducible nitric oxide synthase (iNOS), which causes formation of the inflammatory agent nitric oxide. Yucca phenolics are also anti-oxidants and free-radical scavengers, which may aid in suppressing reactive oxygen species that stimulate inflammatory responses. Based on these findings, further studies on the anti-arthritic effects of Yucca schidigera are warranted.

The Effect of Isoquinoline Alkaloids on Opiate Withdrawal

Our interest has been centered on isoquinoline alkaloids obtained from Argemone mexicana (Papaveraceae), Aristolochia constricta (Aristolochiaceae) and the opium alkaloid, papaverine. In this respect, the effect of these isoquinoline alkaloids was investigated on contractions induced by naloxone of isolated guinea pig ileum acutely exposed to morphine in vitro. The activity of these alkaloids was compared to the control compound, papaverine. Furthermore, the effect of these isoquinoline alkaloids was also determined on naloxone-precipitated withdrawal in isolated guinea pig ileum exposed to DAMGO (highly selective mu opioid receptor agonist) and U50-488H (highly selective kappa opioid receptor agonist) to test whether the possible interaction of isoquinoline alkaloids on opioid withdrawal involves mu- and/or kappa-opioid receptors. Isoquinoline alkaloids from A. mexicana (from 5 x 10(-6) to 1 x 10(-4) M), from A. constricta (1 x 10(-5) x 10(-5)-1 x 10(-4) M) as well as papaverine treatment (1 x 10(-7)-5 x 10(-6)-1 x 10(-6) M) before or after the opioid agonists were able of both preventing and reversing the naloxone-induced contraction after exposure to mu (morphine and DAMGO) or kappa (U50-488H) opiate receptor agonists in a concentration-dependent manner. Both acetylcholine response and electrical stimulation were also reduced by isoquinoline alkaloids and papaverine treatment as well as the final opiate withdrawal was still reduced. The results of the present study indicate that isoquinoline alkaloids as well as papaverine were able to produce significant influence on the opiate withdrawal in vitro and these compounds were able to exert their effects both at mu and kappa opioid agonists.

Hexanic Maca extract improves rat sexual performance more effectively than methanolic and chloroformic Maca extracts

Lepidium meyenii (Maca) is traditionally employed in the Andean region for its supposed properties in improving fertility. The aim of this study was to determine the effect of subacute oral administration of hexanic, methanolic and chloroformic extracts of Maca root on sexual performance in inexperienced male rats. The following sexual performance parameters were evaluated: 1st mount, 1st intromission, ejaculation and post-ejaculatory latencies, intercopulatory interval and copulatory efficacy. All the tested fractions significantly decreased intromission latency and intercopulatory interval and increased intromission frequency and copulatory efficacy (P < 0.05) as compared to controls. Hexanic and methanolic extracts were able to increase mount frequency (MF), while only hexanic fraction significantly improved mount latency (ML) (P=0.038). Globally, only the hexanic fraction significantly improved the majority of the sexual parameters measured. Sub-acute oral administration of hexanic Maca extract improved sexual performance parameters in sexually inexperienced male rats most effectively.

Steroidal saponins of Yucca schidigera Roezl

Eight steroidal saponins have been isolated from Yucca schidigera Roezl. trunk, and their structures were established by spectral (MS and NMR) techniques. These included three novel furostanol glycosides including 3-O-beta-D-glucopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-5 beta(25R)-furostan-3 beta,22 alpha,26-triol 26-O-beta-D-glucopyranoside, 3-O-beta-D-glcopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-5 beta(25R)-furost-20(22)-en-3 beta,26-diol-12-one 26-O-beta-D-glucopyranoside, 3-O-beta-D-glcopyranosyl-(1-->2)-beta-D-glucopyranosyl-5 beta(25R)-furostan-3 beta,22 alpha,26-triol 26-O-beta-D-glucopyranoside, and five known spirostanol glycosides. On the basis of the extraction efficiency, furostanol glycosides made up only 6.8% of total saponins isolated.

Secondary metabolites from the roots of Astragalus zahlbruckneri

Four new phenolic glycosides, beta-apiofuranosyl-(1-->2)-beta-glucopyranosides (1-4), along with the cycloartane triterpenes 20(R),25-epoxy-3beta,6alpha,16beta,24alpha-tetrahydroxycycloartane (5) and 20(R),24(S)-epoxy-3beta,6alpha,25-trihydroxycycloartan-16-one (6) were isolated from roots of Astragalus zahlbruckneri. The structure elucidation of all compounds was based on their (1)H and (13)C NMR spectral data including 1D-TOCSY, DQF-COSY, HSQC, and HMBC experiments.

Naphthopyranone glycosides from Paepalanthus microphyllus

Three new naphthopyranone glycosides, paepalantine-9-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1), paepalantine-9-O-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside (2), and paepalantine-9-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (3), along with the known paepalantine-9-O-beta-D-glucopyranoside (4) were isolated from aerial parts of Paepalanthus microphyllus. These compounds were characterized by spectrometric methods, including electrospray mass spectrometry and 1D and 2D NMR experiments. As a part of our program for screening natural compounds for anti-HIV activity, compounds 1-4 were tested in C8166 cells infected with HIV-1MN.

Xanthones and flavonoids from Leiothrix curvifolia and Leiothrix flavescens

8-Carboxymethyl-1,6-dihydroxy-3,5-dimethoxyxanthone, 8-carboxymethyl-1,5,6-trihydroxy-3-methoxyxanthone and 8-carboxymethyl-1,3,5,6-tetrahydroxyxanthone were isolated from the capitula of Leiothrix curvifolia and Leiothrix flavescens and characterized by spectroscopic methods, mainly 1D and 2D NMR experiments, as well as by electrospray mass spectrometry. Eight known flavonoids were also isolated and they were identified by 1D and 2D NMR experiments and comparison with literature data.

Alfalfa (Medicago sativa L.) flavonoids. 1. Apigenin and luteolin glycosides from aerial parts

Nine flavones and adenosine have been identified in aerial parts of alfalfa, and their structures were established by spectral (FABMS and NMR) techniques. Five of the identified compounds, including apigenin 7-O-[beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[2-O-feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[2-O-feruloyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], apigenin 7-O-[2-O-p-coumaroyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], and luteolin 7-O-[2-O-feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, have not been reported before in the plant kingdom. Additionally, five known compounds, including apigenin 7-O-beta-D-glucuronopyranoside, apigenin 4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[beta-D- glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], luteolin 7-O-beta-D-glucuronopyranoside, and adenosine, were identified.

Resveratrol and other phenolics from the bark of Yucca schidigera roezl

Five phenolic constituents have been identified in Yucca schidigera bark, and their structures were established by spectral (FABMS and NMR) experiments. These included two known stilbenes, trans-3,4',5-trihydroxystilbene (resveratrol) and trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, as well as three novel compounds, yuccaols A, B, and C, with spiro-structures rarely occurring in the plant kingdom. It is suggested that yuccaols A-C are biosynthethized via attachment of a stilbenic derivative to the carbocationic intermediate of the oxidative flavanone-flavonol conversion.

Planifolin, a new naphthopyranone dimer and flavonoids from Paepalanthus planifolius

A new naphthopyranone dimer (1) named planifolin was isolated from a methylene chloride extract of the capitula of Paepalanthus planifolius. The structure of 1 has been determined by chemical and spectroscopic means. In addition, a known dihydronaphthopyranone glycoside and seven known flavonoids were isolated from an ethanolic extract of the leaves of P. planifolius.

A new flavonol glycoside from the aerial parts of Astragalus vulneraria

A new flavonol glycoside, isorhamnetin 3-O-beta-D-apiofuranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-galactopyranoside, and the known diglycoside, isorhamnetin 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside were isolated from the aerial parts of Astragalus vulneraria. Characterization of the two compounds was done by spectroscopic methods (1D and 2D NMR, and FAB-MS).

Constituents of Croton menthodorus and their effects on electrically induced contractions of the guinea-pig isolated ileum

The present study examines the effects of the extracts [petroleum ether, CHCl(3), CHCl(3)MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Croton menthodorus on the electrically induced contractions of the isolated guinea-pig ileum (ECI). The results of the experiments indicate that CHCl(3)/MeOH (9:1) and MeOH extracts, tested at concentrations of 100, 50 and 25 microg/mL, dose-dependently reduced the guinea-pig ileum contractions, whereas petroleum ether and CHCl(3) extracts did not affect it. Furthermore, the partially purified fractions III-VI from the CHCl(3)/MeOH extract, each tested at concentrations of 100, 50 and 25 microg/mL also inhibited ECI. Finally, pure compound 1 (6 x 10(-6), 3 x 10(-6), 1 x 10(-6) M) isolated and purified from the most active fraction III significantly reduced, in a dose-dependent manner, the electrical contractions of the ileum. Compound 1 was identified by NMR and EI-MS data as the morphinandien-7-one, O-methylflavinantine.

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.

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.

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.

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. Structure elucidation of compounds 1-6 was accomplished through the extensive use of 1D and 2D NMR techniques. In addition, a new oleanene glycoside (7) and a new tryptophan derivative (8) were also isolated and characterized.

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. IC50 values calculated for quercetin, flavone, catechin and chrysin were 2.7 x 10(-6), 7.3 x 10(-7), 8.5 x 10(-7) and 5.3 x 10(-6) M, respectively. These results suggest that flavonoids might play an important role in the control of morphine withdrawal.

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. Their structures were elucidated by 1D and 2D NMR experiments including 1H-1H (DQF-COSY, 1D TOCSY, 2D HOHAHA, ROESY) and 1H-13C (HSQC, HMBC) spectroscopy.

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. Although the MeOH extract and pregnane glycosides (at different doses) were found to promote platelet aggregation, flavinantine (3) and O-methylflavinantine (4) showed only slight activity. The ability of the MeOH extract and the four compounds to act synergistically with thrombin was also evaluated. All the tested compounds were successful in augmenting the aggregating effect of thrombin, although to different degrees.

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. mexicana significantly and in a concentration-dependent manner reduced the morphine withdrawal. Since the pure compounds were identified as protopine and allocryptopine, the observed effects could be related to these compounds. The results of the present study suggest that isoquinoline alkaloids may be potential agents in the treatment of drug abuse.

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. On the other hand the pentahydroxyflavone (quercetin, 2) and two 3-substituted derivatives of kaempferol appeared to inhibit HIV-infection by preventing binding of gp120 to CD4. 2-Phenylethanol-O-(6-O-galloyl)-beta-D-glucopyranoside 8 interacted irreversibly with gp120 and neutralized virus infectivity. The differences in the modes of action of 1 and 8 can account for the apparent synergy of their anti-viral activities.

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. All isolated compounds from W. ciliolata and W. dactylophylla were tested in vitro for anti-viral activity against HIV-1, but only 6-hydroxytremetone showed a significant anti-HIV-1 activity.

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. The aglycone moieties are the oleane-type triterpenes cyclamiretin A for 1 and the new 13,28-epoxy-30,30-dimethoxyolean-3 beta, 16 alpha-diol and 3 beta, 16 alpha-dihydroxy-13,28-epoxyolean-29-oic acid for 2 and 3, respectively.

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.