Saponins from Lysimachia candida

Three saponins were isolated from Lysimachia candida Lindl. By spectral and chemical analysis, they were identified as primulagenin A-3-O-β-D-xylopyranosy( 1→2)-β-D-glucopyranosyl( 1→4)-[β-D-glu- copyranosyl(1→2) ] -a-L-arabinopyranoside ( 1 ), protoprimulagenin A-3-O-β-D-xylopyranosyl( 1→2)-β-D-glu- copyranosyl( 1→4)-[ β-D-glucopyranosyl ( 1 →2) ]-a-L-arabinopyranoside ( lysikoianoside, 2) and a-spinas- teml-glucopyranoside (3) respectively. 1 is a new compound named candidoside.     

Isolation and Identification of Steroidal Saponins from Dioscorea parviflora Ting

Four steroidal saponins were isolated from rhizomes of Dioscorea parvi- flora Ting collected from Yunnan Province. Their chemical structures have been elucidated by means of chemical and spectrometric analyses as gracillin [Ⅰ]; deltonine [Ⅱ]; protogracillin [Ⅲ] and deltoside [Ⅳ]. Deltoside is the first time obtained in pure state from Dioscorea plants.     

Akebia saponin D, a saponin component from Dipsacus asper Wall, protects PC 12 cells against amyloid-β induced cytotoxicity

According to Traditional Chinese Medicine, Alzheimer's disease (AD) is regarded as senile dementia, and the etiopathogenesis lies in kidney deficiency during aging. Dipsacus asper Wall (DAW), a well-known traditional Chinese medicine for enhancing kidney activity, may possess the therapeutic effects against AD. Our objectives were to investigate the protective effects of DAW against the amyloid-β peptide (Aβ)-induced cytotoxicity and explore its major active components. Injury of PC 12 cells mediated by Aβ_25–35 was adopted to assess the cytoprotective effects of DAW aqueous extract and various fractions. Salvianolic acid B, a polyphenol compound isolated from Salvia miltiorrhiza, was employed as a positive control agent due to its markedly protective effect against neurotoxicity of amyloid β. Five chemical fractions (i.e. alkaloids, essential oil, saponins, iridoid glucoside and polysaccharides) were prepared for activity test and analyzed by HPLC for active components identification. In addition, Akebia saponin D (the most important compound in DAW saponins) and hederagenin (the mother nucleus of akebia saponin D) were prepared for testing of their activity. DAW water extract, saponins fraction and akebia saponin D had the neuroprotective capacity to antagonize Aβ_25–35-induced cytotoxicity in PC 12 cells. In contrast, other fractions and hederagenin had no cytoprotective action. This research suggests that DAW may represent a potential treatment strategy for AD and akebia saponin D is one of its active components.     

Estimation of flavonoid and centelloside accumulation in leaves of Centella asiatica L. Urban by multiparametric fluorescence measurements

Recently, we have shown the relevance of nitrogen (N), phosphorus (P) and potassium (K) supply levels for resource partitioning between primary and secondary metabolism, and the concentration of centellosides in Centella asiatica L. Urban leaves. So far, no efforts have been made to investigate the effects of mineral supply on flavonoid concentrations in this species. Here, we aimed to examine the accumulation of centellosides in C. asiatica leaves in vivo by means of non-destructive fluorescence measurements using products of the secondary metabolism, particularly the epidermal flavonols and anthocyanins, as reference. For this purpose we conducted three discrete experiments in a greenhouse having N, P and K levels as experimental factors. Our results reveal that flavonoid and anthocyanin accumulation is affected by N, P and K fertigation in the same way as the centelloside accumulation. More precisely, limitations in plant growth were accompanied by higher flavonoid and anthocyanin concentrations, confirming the proposed trade-off between the plant's primary and secondary metabolism. The fluorescence-based flavonol (FLAV) and anthocyanin (ANTH_RG) indices correlated fairly with flavonoid and especially with anthocyanin concentrations. Moreover, centellosides were positively correlated with the FLAV and ANTH_RG indices, and with the BFRR_UV index, which is considered as universal ‘stress-indicator’. Thus, here we indicate for the first time, that the fluorescence-based indices FLAV, ANTH_RG as well as BFRR_UV enable the monitoring of flavonoid and centelloside concentrations in leaves of C. asiatica. Our results support and highlight the significant potential for further development and application of fluorescence-based sensors in ecophysiological research as well as in the production of medicinal plants.     

Concise synthesis of two trisaccharides related to the cytotoxic triterpenoid saponin isolated from Pithecellobium lucidum

Convergent synthesis of two trisaccharides related to the cytotoxic triterpenoid saponin isolated from Pithecellobium lucidum is reported. The trisaccharides are synthesized in the form of their propargyl glycosides to leave the scope for further glycoconjugate formation through various multi-component reactions. A simple protecting group manipulation is followed using commercially available monosaccharides, d-glucose, d-xylose, d-fucose and l-rhamnose. H₂SO₄ immobilized on silica is used as the Brönsted acid source for the N-iodosuccinimide-mediated thioglycoside activation for stereoselective glycosylations and proved to be a better choice over traditional Lewis acid catalysts such as TMSOTf and TfOH.     

Anti-arthritogenic effect of Saponin-1 by alteration of Th1/Th2 cytokine paradigm in arthritic mice

Objective & designInvestigation was carried out on Saponin 1 (SAP-1), a novel molecule isolated from Parthenium hysterophorus, on proinflammatory (Th1) & anti-inflammatory (Th2) cytokines in blood of arthritic balb/c mice.MethodsAdjuvant induced developing inflammatory arthritis was induced in mice which were treated with SAP-1 in graded oral doses. The molecular markers were determined using Flow Cytometry which uses sensitivity of amplified fluorescence detection to measure soluble analytes in particle based immune assay. The T-helper (Th1) deviated cells produce detectable level of Tumor necrosis factor (TNF-alpha), interleukin-2 (IL-2) & interferon-gamma (IFN-gamma), while the Th2 deviated cells produce significant amount of interleukin-4 (IL-4) and interleukin-5 (IL-5).ResultsSAP-1 at graded oral doses inhibited expression of IFN-gamma & TNF-alpha in serum & correspondingly increased expression of IL-4 significantly. SAP-1 also inhibited IL-17 and CD4⁺CD25⁺ cell population showing to have suppressive effect on Th-17 pathway as well as T-regulatory cells. It also suppressed the increased levels of pro-inflammatory mediators like IL-1β and NO. Inhibitors of Cox-2 and MCP-1 provide effective improvements in signs and symptoms of Rheumatoid Arthritis. SAP-1 decreased the elevated concentration of both COX-2 and MCP-1 in arthritic animals.ConclusionsSAP-1 diminishes Th1 immunity activation, a primary cause of arthritis, in favour of Th2 dominance, which reduces arthritic condition in mice displaying immune-modulatory potential.     

Synthesis of alginate‐silica hybrid hydrogel for biocatalytic conversion by β‐glucosidase in microreactor

The organic–inorganic hybrid materials have been used in different fields to immobilize biomolecules since they offer many advantages. The aim of this study was to optimize and characterize the alginate‐silica hybrid hydrogel as a stable and injectable form for microfluidic systems using internal gelation method and increase the stability and activity of immobilized enzyme for biocatalytic conversions as well. Characterization was carried out by scanning electron microscopy, energy dispersive spectroscopy/mapping, Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and Fourier‐transform infrared spectroscopy analyses, and the shrinkages of monoliths were evaluated. Subsequent to optimizing the enzyme concentration (40 μg), hydrolytic conversion of 4‐nitrophenyl β‐d ‐glucopyranoside (pNPG) was performed to understand the behavior of the bioconversion in the microfluidic system. The yield was 94% which reached the equilibrium at 24 h indicating that the alginate‐silica gel derived microsystem overcome some drawbacks of monolithic systems. Additionally, bioconversion of Ruscus aculeatus saponins was carried out at the same setup in order to obtain aglycon part, which has pharmaceutical significance. Although pure aglycon could not be achieved, an intermediate compound was obtained based on the HPLC analysis. The developed formulation can be utilized for various life science applications.     

Cell lysis induced by membrane-damaging detergent saponins from Quillaja saponaria

This paper presents the results of a study to determine the effect of Quillaja saponaria saponins on the lysis of industrial yeast strains. Cell lysis induced by saponin from Q. saponaria combined with the plasmolysing effect of 5% NaCl for Saccharomyces cerevisiae, Kluyveromyces marxianus yeasts biomass was conducted at 50 °C for 24–48 h. Membrane permeability and integrity of the yeast cells were monitored using fluorescent techniques and concentrations of proteins, free amino nitrogen (FAN) and free amino acids in resulting lysates were analyzed. Protein release was significantly higher in the case of yeast cell lysis promoted with 0.008% Q. saponaria and 5% NaCl in comparison to plasmolysis triggered by NaCl only.     

FDS,a novel saponin isolated from Felicium decipiens: Lectin interaction and biological complementary activities

Filicium decipiens saponin (FDS) is the first saponin purified from F. decipiens seeds using ion-exchange and gel filtration chromatographies. In the present study, FDS and the aqueous crude extract of F. decipiens seeds were examined for their antifungal properties, hemolytic/cytotoxicity activity. The dried seeds were powdered and homogenized in 10% (w/v) for the preparation of crude extract. Sample obtained from Sephadex-LH-20 demonstrated FDS with a peak at 752.35 g/mol. FDS showed the highest toxicity against Aspergillus flavus, presenting with a low fungicidal concentration at 12.8 μg/mL. Under hemolytic induction, rabbit and cow erythrocytes were more affected by both samples, and the inhibition effect of PpyLL lectin was observed. These characteristics provide fundamental understanding of F. decipiens secondary metabolites, which would benefit future research to prevent dangerous traditional uses and provide agricultural solution.