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Biomedical subjects

J P Parente

Publications and source records attributed to J P Parente.

At least 19 recordsLinked to original sources
PubMed2006

Acylated and deacylated saponins of Quillaja saponaria mixture as adjuvants for the FML-vaccine against visceral leishmaniasis.

The adjuvant of the FML-vaccine against murine and canine visceral leishmaniasis, the Riedel de Haen saponin mixture, was fractionated by ion exchange chromatography on DEAE-cellulose to afford one TLC homogeneous Quillaja saponaria Molina QS21 saponin fraction (18.0%), a mixture of two deacylsaponins (19.4%), sucrose (39.9%), sucrose and glucose (19.7%), rutin (0.8%) and quercetin (2.2%), that were identified by comparison of 1H and 13C NMR spectroscopy. The QS21 shows the typical aldehyde group in C-23 (65% equatorial) and a normonoterpene moiety acylated in C-28. The deacylsaponins show the aldehyde group but do not have the normonoterpene moiety. Balb/c mice were vaccinated with 150 microg of FML antigen of Leishmania donovani and 100 microg of each obtained fraction and further challenged by infection with 10(8) amastigotes of Leishmania chagasi. The safety analysis and the effect on humoral and cellular immune responses and in clinical signs showed that the QS21 saponin and the deacylsaponins are the most active adjuvant compounds of the Riedel the Haen saponin mixture. Both induced the highest and non-significantly different increases in DTH, CD4+ T lymphocytes in spleen, IFN-gamma in vitro, body weight gain and the most pronounced reduction of parasite burden in liver (95% for QS21 and 86% for deacylsaponins; p>0.05). While the QS21 showed mild toxicity, significant adjuvant effect on the anti-FML humoral response before and after infection, and decrease in liver relative weight, the deacylsaponins showed no toxicity, less haemolysis and antibody and DTH responses increased mainly after infection, still inducing a stronger Leishmania-specific in vitro splenocyte proliferation. Our results confirm in the Riedel de Haen saponin extract the presence of deacylsaponins normonoterpene-deprivated which are non-toxic and capable of inducing a specific and strong immunoprotective response in vaccination against murine visceral leishmaniasis.

Acylation↗
PubMed2004

Protective vaccination against murine visceral leishmaniasis using aldehyde-containing Quillaja saponaria sapogenins.

The presence of aldehyde groups at C-23 and C-24 of the triterpen aglycon moiety was disclosed in 1H NMR spectra of both the Riedel de Haen saponin (R) (delta 9.336) and Quillaja saponaria QuilA saponin (delta 9.348). The sign of the C-28 acylated linked moiety (delta 176) was present in both saponins, while the delta 171 at C-28 (carboxy group) corresponding to the deacylated saponin, was only detected in the QuilA preparation, indicating 50% of hydrolysis of the ester moiety, probably due to the storage in aqueous solution. The normoterpen moiety was present in both saponins (signals at delta 14-18). The chemical removal of saponin glicidic moieties gave rise to their sapogenin fractions. Their 1H NMR spectra showed the presence of two signals (delta 9.226 and 9.236) for sapogenin R and two signals (delta 9.338 and 9.352) for the QuilA sapogenin. The intensity of the signals suggested two conformational isomers of sapogenin R in the ratio 53% of equatorial aldehyde group to 47% of axial aldehyde group, and two conformational isomers of QuilA sapogenin in the ratio 76% of equatorial aldehyde group to 24% of axial aldehyde group. The chemical treatment abolished the saponin slight in vivo toxicity, reduced their hemolytic potential, did not affect their aldehyde contents, but gave rise to an enriched axial aldehyde-containing sapogenin R with enhanced potential on antibody humoral response (anti-IgM, IgG, IgG1, IgG2a, IgG2b and IgG3) and to an enriched equatorial aldehyde-containing QuilA-sapogenin that induced a mainly cellular specific immune response (increased intradermal response to leishmanial antigen and IFNgamma sera levels) and effective protection against murine infection by L. donovani (77% reduction in liver parasitic load). Our results suggest that the Riedel de Haen saponin is probably a Quillaja saponaria saponin.

Adjuvants, Immunologic↗
PubMed2001

An anti-inflammatory and immunomodulatory polysaccharide from Orbignya phalerata.

A polysaccharide, a glucan with mean M(r) of 1.0 x 10(6) (MP1), was isolated from the mesocarp of fruits of Orbignya phalerata. Chemical and spectroscopic studies indicated that MP1 has a highly branched glucan type structure composed of alpha-(1-->4) linked D-glucopyranose residues with (3-->4), (4-->6), and with (3-->6) branching points. MP1 enhanced phagocytosis in vivo and exhibited anti-inflammatory activity.

Adjuvants, Immunologic↗
PubMed2000

Anti-inflammatory and immunologically active polysaccharides of Periandra mediterranea.

Three polysaccharides, glucans with mean M(r)'s of 1.5 x 10(5), 3.6 x 10(4) and 2.1 x 10(4), were isolated from dried roots of Periandra mediterranea by fractionation on Sephacryl S-300 HR and Sephadex G-25. Chemical and spectroscopic studies indicated that they have a highly branched glucan type structure composed of alpha-(1-->4) linked D-glucopyranose residues with both (3-->4) and (4-->6) branching points. The polysaccharides enhance phagocytosis in vivo, and exhibit anti-inflammatory activity.

Adjuvants, Immunologic↗
PubMed2000

Flavonol glycosides from Costus spicatus.

Two flavonol diglycosides, tamarixetin 3-O-neohesperidoside, kaempferide 3-O-neohesperidoside and the known quercetin 3-O-neohesperidoside, together with six other known flavonoids were isolated from the leaves of Costus spicatus and their structures were elucidated by a combination of spectroscopic and chemical methods. The flavonol diglycosides were evaluated for inhibitory activity of nitric oxide production by activated macrophages (Fig. 1).

Animals↗
PubMed2000

Flavonol glycosides from leaves of Costus spiralis.

A new flavonol diglycoside, 3,5-dihydroxy-7,4'-dimethoxyflavone 3-O-neohesperidoside (1), together with four known flavonol 3-O-neohesperidosides were isolated from the leaves of Costus spiralis and their structures were elucidated by a combination of spectroscopic methods and chemical reactions.

Flavonoids↗
PubMed2000

Immunologically active polysaccharides from Centrosema pubescens.

Two polysaccharides with mean M(r)s of 2.0 x 10(6) and 3.75 x 10(5), were isolated from powdered seeds of Centrosema pubescens by fractionation on Sephacryl S-300 HR. Chemical and spectroscopic studies indicated that they have a backbone chain composed of beta-(1-->4)-linked D-galactopyranose residues having branches composed of alpha-(1-->5)-linked L-arabinofuranose residues at position 6 of D-galactose of the backbone chain. The polysaccharides showed reticuloendothelial system-potentiating activity in a carbon clearance test.

Animals↗
PubMed2000

Biochanin A triglycoside from Andira inermis.

A new isoflavonol triglycoside, biochanin A 7-O-beta-D-apiofuranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->6 )-beta-D- glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside and lanceolarin.

Genistein↗
PubMed1999

A furostanol glycoside from rhizomes of Costus spicatus.

A new furostanol glycoside was isolated from the rhizomes of Costus spicatus. Its structure was established as (3 beta,22 alpha,25R)-26-(beta -D-glucopyranosyloxy)-22-methoxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->2)-O-[6-deoxy-alpha-L-mannopyranosy l-(1-->4)]- beta-D-glucopyranoside. The structural identification was performed using detailed analysis of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR and COLOC) and chemical conversions.

Carbohydrate Conformation↗
PubMed1999

A new steroidal saponin from the rhizomes of Costus spicatus.

A new steroidal saponin has been isolated from the rhizomes of Costus spicatus and its structure was elucidated as (3 beta, 22 alpha, 25R) -26-(beta-D-glucopyranosyloxy)-2-methoxyfurost-5-en-3-yl O-D-apio-beta-D-furanosyl-(1-->4)-O-[alpha-L-rhamnopyranosyl-(1--> 2)]- beta-D-glucopyranoside by means of IR, MS, NMR and chemical evidence.

Carbohydrate Sequence↗
PubMed1997

Haemolytic activities of plant saponins and adjuvants. Effect of Periandra mediterranea saponin on the humoral response to the FML antigen of Leishmania donovani.

An 87.7% (P < 0.01) and 84% (P < 0.001) of protection against visceral leishmaniasis was achieved in CB hamsters and Balb/c mice, respectively, with saponin combined to the fucose-mannose ligand of Leishmania donovani (FML). However, an undesirable haemolytic effect was described for several saponins. Aiming to improve the formulation with FML/saponin, we comparatively analysed the haemolytic potential of recently characterized plant saponins and currently used adjuvants. The haemolytic activity of steroidic saponins from Agave sisalana; Smilax officinalis as well as commercial saponin (Riedel De Haën's), was higher than that of triterpenoid ones (Bredemeyera floribunda; Periandra mediterranea) and the Freund's complete adjuvant. The concentration resulting in 50% haemolysis was 500 micrograms ml-1 for aluminum hydroxide. The low haemolytic effect of P. mediterranea saponin was abolished by removal of its glycidic moiety and its sapogenin fraction as well as the Freund's Incomplete Adjuvant were non-haemolytic within this range. Furthermore, the adjuvant effect of three doses of P. mediterranea saponin injected with the FML antigen of L. donovani, was assayed in mice, either by the intraperitoneal (i.p.) or the subcutaneous (s.c.) route. The anti-FML IgG antibody levels increased and detectable levels were observed up to 3 months in the s.c. group. The response was expanded in both groups after an injection with a fourth vaccine dose. The IgG response showed increased levels of IgG2a only in the i.p. group, while IgG2b and IgG1 but not IgG3 antibodies were higher than controls in both groups. In conclusion, the results suggest that the recently described triterpenoid fractions of P. mediterranea can be safely used as adjuvant with low or non-haemolytic effect.

Adjuvants, Immunologic↗
PubMed1996

Steroidal saponins from Smilax officinalis.

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.

Carbohydrate Conformation↗
PubMed1996

A new triterpenoid saponin, bredemeyeroside B. from the roots of Bredemeyera floribunda.

A new triterpenoid saponin named bredemeyeroside B has been isolated from the roots of Bredemeyera floribunda and its structure elucidated as 3-O-beta-D-glucopyranosyl-2 beta, 3 beta, 27-trihydroxyolean-12-en-23,28-dioic acid 28-O-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl-(1-->3)]-a lpha -L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->3] -beta-D-fucopyranoside by means of MS, NMR and chemical evidence. In addition rutin was also isolated. In laboratory tests bredemeyeroside B showed snake venom antidote activity.

Antivenins↗
PubMed1994

Pharmacological screening of plants recommended by folk medicine as snake venom antidotes; IV. Protection against jararaca venom by isolated constituents.

Fifteen compounds, isolated from plants reputed as snake venom antidotes, belonging to different classes of natural products, were shown to protect mice to a significant degree against the lethal action of the venom of Bothrops jararaca snakes. Administration was by the oral route, one hour prior to envenomation. The substances are nitrogen-free, low-molecular-weight compounds for which some kind of biodynamic activity has previously been reported. The fact that they are mostly trivial, naturally-occurring compounds should explain why plants used as snake-bite antidotes are so widely distributed over the plant kingdom.

Animals↗
PubMed1989

Neutralization of lethal and myotoxic activities of South American rattlesnake venom by extracts and constituents of the plant Eclipta prostrata (Asteraceae).

Ethanolic extracts of the aerial parts of Eclipta prostrata L. (Asteraceae) neutralized the lethal activity of the venom of South American rattlesnake (Crotalus durissus terrificus) when mixed in vitro before i.p. injection into adult Swiss mice. Samples of ethanolic extract corresponding to 1.8 mg of dry extract per animal neutralized up to four lethal doses of the venom (LD50 = 0.08 micrograms venom/g animal). Three substances isolated from the plant--wedelolactone (0.54 mg/animal), sitosterol (2.3 mg/animal) and stigmasterol (2.3 mg/animal)--were able to neutralize three lethal doses of the venom. Aqueous extracts of the plant inhibited the release of creatine kinase from isolated rat muscle exposed to the crude venom. The protection conferred against the myotoxic effects of the venom could be demonstrated also in vivo, when the venom was preincubated with the extract prior to injection into mice.

Animals↗
PubMed1986

Separation of sialyl-oligosaccharides by high-performance liquid chromatography. Application to the analysis of mono-, di-, tri- and tetrasialyl-oligosaccharides obtained by hydrazinolysis of alpha 1-acid glycoprotein.

High-performance liquid chromatography has been applied to the separation of isomers of mono-, di-, tri- and tetrasialylated oligosaccharides derived from alpha 1-acid glycoprotein by hydrazinolysis. The separation of the sialyl-oligosaccharides on the basis of their negative charges was carried out with quaternary amine-bonded silica. Within each class, the anionic oligosaccharides were fractionated on the basis of their net carbohydrate content on alkylamine-modified silica using a mobile phase consisting of a mixture of acetonitrile and potassium dihydrogen phosphate with 0.01% of 1,4-diaminobutane or 0.01% of tetraethylpentamine.

Chromatography, Gas↗
PubMed1985

A convenient method for methylation of glycoprotein glycans in small amounts by using lithium methylsulfinyl carbanion.

Treatment of dimethyl sulfoxide with butyllithium leads to rapid formation of lithium methylsulfinyl carbanion. The reaction products tend to be significantly freer from impurities when lithium methylsulfinyl carbanion is used rather than sodium or potassium methylsulfinyl carbanion. This reagent gives less background in g.l.c. and thus may be used to methylate micro-quantities of glycoprotein glycans (down to 10 micrograms) without the necessity of identifying methyl ethers by mass spectrometry.

Animals↗