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PubMed1992

[Ca2+ channel blocking effect of panaxadiol saponins and panaxatriol saponins of cultured cardiac cells].

It was found that PDS and PTS decreased the action potential parameters of the cultured myocardiocytes in a dosage-dependent way. The effects of PDS 1000 micrograms/ml, PTS 200 micrograms/ml were in correspondence with the known Ca2+ channel blocker Mn2+ 0.05 micrograms/ml. Washing out, administration of epinephrine 10 micrograms/ml or Ca2+ 80 micrograms/ml were able to reverse the action potential from inhibition. The above results indicate that both PDS and PTS have Ca2+ channel blockade action.

Action Potentials↗
PubMed2002

Chromatographic determination of plant saponins.

The methods used for saponin determination in plant materials are presented. It is emphasised that the biological and spectrophotomeric methods still being used for saponin determination provide, to some extent, valuable results on saponin concentrations in plant material. However, since they are sensitive to the structural variation of individual saponins they should be standardized with saponin mixtures isolated from the plant species in which the concentration is measured. However, one plant species may contain some saponins which can be determined with a biological test and others which cannot. That is why biological and colorimetric determinations do not provide accurate data and have to be recognized as approximate. Thin-layer chromatography on normal and reversed-phases (TLC, HPTLC, 2D-TLC) provides excellent qualitative information and in combination with on-line coupling of a computer with dual-wavelength flying-spot scanner and two-dimensional analytical software can be used for routine determination of saponins in plant material. The densitometry of saponins has been very sensitive, however, to plate quality, spraying technique and the heating time and therefore appropriate saponin standards have to be run in parallel with the sample. Gas-liquid chromatography has limited application for determination since saponins are quite big molecules and are not volatile compounds. Thus, there are only few applications of GC for determination of intact saponins. The method has been used for determination of TMS, acetyl or methyl derivatives of an aglycones released during saponin hydrolysis. However, structurally different saponins show different rates of hydrolysis and precise optimisation of hydrolysis conditions is essential. Besides, during hydrolysis a number of artefacts can be formed which can influence the final results. High performance liquid chromatography on reversed-phase columns remains the best technique for saponin determination and is the most-widely used method for this group of compounds. However, the lack of chromophores allowing detection in UV, limits the choice of gradient and detection method. The pre-column derivatisation with benzoyl chloride, coumarin or 4-bromophenacyl bromide has been used successfully in some cases allowing UV detection of separation. Standardisation and identification of the peaks in HPLC chromatograms has been based on comparison of the retention times with those observed for authentic standards. But new hyphenated techniques, combining HPLC with mass spectrometry and nuclear magnetic resonance are developing rapidly and allow on-line identification of separated saponins. Capillary electrophoresis has been applied for saponin determination only in a limited number of cases and this method is still being developed.

Chromatography, Gas↗
PubMed2002

Degradation of Quillaja saponaria Molina saponins: loss of the protective effects of a herpes simplex virus 1 subunit vaccine.

Quillaja saponins (Q. saponins) are readily hydrolyzed at neutral pH to yield degraded deacylated saponins (DS-saponins). Degradation of Q. saponins resulted in some reduction of their capacity to elicit IgG1, IgG2a and IgG2b isotypes against the highly immunogenic envelope glycoprotein D (gD) from herpes simplex virus, type 1 (HSV-1). Addition to gD of a dose of DS-saponins tenfold higher than the original Q. saponins dose stimulated lower IgG2a and IgG2b titers than those obtained with gD alone or combined with native saponins. However, the IgG1 response was somewhat similar in all the groups. In contrast, Q. saponins' deacylation resulted in a significant reduction in both the production of HSV-1 neutralizing antibodies and survival rates after viral challenge. Vaccination with gD alone did not protect mice against a lethal challenge with HSV-1, while the addition of Q. saponins to gD resulted in protection against HSV-1. Vaccines containing partially deacylated saponins yielded lower survival rates, while vaccines containing DS-saponins did not protect mice against HSV-1. Increasing the dose of DS-saponins tenfold resulted in a marginal increase in protection. These results show that degradation of Q. saponins during storage can have a deleterious effect on vaccines' efficacies.

Animals↗
PubMed2004

Induction of cell death by saponin and antigen delivery.

PURPOSE: Saponin is the major component in the formation of immune stimulating complex (ISCOM), a potent adjuvant able to induce both humoral and cellular immune reactions. The immunogenicity induced by saponin, however, has been unclear. The objective of this study was to investigate the apoptotic and necrotic effects induced by saponin in ELA mouse lymphoma cells, expected to be a possible mechanism of the cytotoxic T-lymphocyte (CTL) effect elicited by the ISCOM. METHODS: EL4 cells were treated with saponin, and viability of the cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase release assays. Fluorescence microscopy was used to detect the morphological changes by staining saponin-treated cells with Hoechst 33342. Extent of apoptosis and necrosis was determined by Annexin V-FITC/propidium iodide staining, followed by flow cytometric analysis. Dendritic cells were cultured with either saponin-protein complexes or saponin-treated cells and analyzed by flow cytometry. RESULTS: Treatment of EL4 cells with saponin resulted in concentration-dependent cytotoxicity and the appearance of the hypodiploid DNA peak. Cells treated with saponin showed highly condensed chromatin when stained with fluorescent DNA-binding dye Hoechst 33342. Analysis of EL4 cells by flow cytometry after Annexin V/propidium iodide staining demonstrated that saponin induced both apoptosis and necrosis. Pretreatment of EL4 cells with zVAD-fmk, a broad-range caspase inhibitor, did not prevent cell death induced by saponin, indicating the non-caspase-dependent cell death. Dendritic cells were shown to phagocytose both the antigen-saponin complexes and the saponin-induced dead cells. CONCLUSIONS: Results obtained in this study demonstrated that saponin induced both apoptosis and necrosis in ELA cells. These events are critical for antigen processing and presentation.

Adjuvants, Immunologic↗