Polar Saponins Research Articles

Natural products and analogs as preventive agents for metabolic syndrome via peroxisome proliferator-activated receptors: An overview.

Natural products and synthetic analogs have drawn much attention as potential therapeutical drugs to treat metabolic syndrome. We reviewed the underlying mechanisms of 32 natural products and analogs with potential pharmacological effects invitro, and especially in rodent models and/or patients, that usually act on the PPAR pathway, along with other molecular targets. Recent outstanding total syntheses or semisyntheses of these lead compounds are stated. In general, they can activate the transcriptional activity of PPARα, PPARγ, PPARα/γ, PPARβ/δ, PPARα/δ, PPARγ/δ and panPPAR as weak, partial agonists or selective PPARγ modulators (SPPARγM), which may be useful for managing obesity, type 2 diabetes (T2D), dyslipidemia and non-fatty liver disease (NAFLD). Terpenoids is the largest group of compounds that act as potential modulators on PPARs and are comprised from small lipophilic cannabinoids to lipophilic pentacyclic triterpenes and polar saponins. Shikimates-phenylpropanoids include polar heterocyclic flavonoids and phenolic compounds containing at least one C3-C6 unit and usually a double bond on the propyl chain. Quercetin (19), resveratrol (24) and curcumin (27), stand out from this group for exhibiting beneficial effects on patients. Alkaloids, the minor group of potential modulators on PPARs, include berberine (30), which has been widely explored in preclinical and clinical studies for its potential beneficial effects on T2D and dyslipidemia. However, large-scale clinical trials may be warranted for the promising compounds.

Less polar ginsenosides have better protective effects on mice infected by Listeria monocytogenes

Listeria monocytogenes widely exists in the natural environment and does great harm, which can cause worldwide public safety problem. Infection with L. monocytogenes can cause rapid death of Kupffer cell (KCs) in liver tissue and liver damage. American ginseng saponins is a natural compound in plants, which has great potential in inhibiting L. monocytogenes infection. Therefore, American ginseng stem-leaf saponins (AGS) and American ginseng heat-transformed saponins (HTS) were used as raw materials to study their bacteriostatic experiments in vivo and in vitro. In this experiment, female Kunming mice were randomly divided into five groups: control group, negative group, AGS group, HTS group (10 mg/kg/day in an equal volume via gastric administration) and penicillin group, each group containing six mice. Profiles AGS and HTS components were evaluated by high-performance liquid chromatography (HPLC) analysis. The bacteriostatic effect of AGS and HTS on L. monocytogenes was evaluated by inhibition zone test, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The bacteriostatic effect of AGS and HTS pretreatment on mice infected with L. monocytogenes were studies by animal experimental. The results showed that the content of polar saponins in AGS was 0.81 ± 0.003 mg/mg, less polar saponins was 0.08 ± 0.02 mg/mg, the content of polar saponins in HTS was 0.10 ± 0.01 mg/mg, less polar saponins was 0.76 ± 0.02 mg/mg. The in vitro bacteriostatic diameter of HTS (16.6 ± 0.8 mm) is large than that of AGS (10.2 ± 1.2 mm). AGS and HTS pretreatment could reduce the colony numbers in the livers of mice infected with Listeria monocytogenes. The levels of alanine aminotransferase (ALT), IL-1β, IL-6, TNF-α and IFN-γ in the livers of mice in the pretreatment group were significantly lower than those in the negative group. There were obvious leukoplakia, calcification and other liver damage on the liver surface in the negative control group, and obvious inflammatory cell infiltration in HE sections. AGS and HTS pretreatment can reduce liver injury caused by L. monocytogenes and protect the liver. Compared with AGS, HTS has higher content of less polar saponins and better bacteriostatic effect in vitro. The count of bacterial in liver tissue of HTS group was significantly lower, the survival rate was significantly higher than that of AGS group. Less polar saponins had better bacteriostatic effect. Collectively, less polar saponins pretreatment has a protective effect on mice infected with L. monocytogenes, to which alleviated liver damage, improved anti-inflammatory ability and immunity of the body, protected liver may contribute.

Reducing the damage of quinoa saponins on human gastric mucosal cells by a heating process.

Different food processing methods will influence the structure and activity of compounds. In this work, molecular structure and different content crude saponins that were extracted from quinoa, treated with water soaking, water boiling, and water steaming were analyzed by HPLC. Flow cytometry was employed to investigate the effects of the main saponins on the GES‐1 cell line. HPLC/MS analysis revealed that water soaking induced an extensive conversion of polar saponin Qc (424.41 ± 21.11 mg/g) to the less polar compound Qf (247.04 ± 15.71 mg/g). After treatment with 100 μg of Qf instead of Qc for 24 hr, the percentage of dead cells increased from 20.1 ± 2.2% to 86.2 ± 4.8%. One major reason of this result is that less polar saponins could damage membrane integrity more easier than polar saponins. The results indicate that saponin toxicity is enhanced after degradation, so it is necessary to avoid degradation before use.

Triterpene saponins from tea seed pomace (Camellia oleifera Abel) and their cytotoxic activity on MCF-7 cells in vitro

Triterpenoid saponins are the main active ingredients extracted from Camellia oleifera Abel. In this study, crude saponins (Tc) was extracted from tea seed pomace and purified to obtain total saponins (T0). We used a COSMOSIL C18-OPN to separate T0 into three fractions—highly polar saponins (T1), moderately polar saponins (T2), and weakly polar saponins (T3). HPLC-ESI-MS analysis revealed that T2 were mainly composed of components with m/z ([M-H]–) of 1201.5617, 1187.5822, 1245.5862, and 1215.5779. Cell cycle analysis showed that both T0 and T2 inhibited proliferation and induced S phase arrest of MCF-7 cells. Further cell invasion assays demonstrated T0 and T2 also significantly reduced the invasive potential of MCF-7 cells. So T2 extracted from tea seed pomace (Camellia oleifera) may have effective antitumor activity.

LC-MS analysis of saponins of Achyranthes root in the Japanese market.

LC-MS analyses of saponin fractions of Achyranthes roots in the Japanese market revealed that there were three patterns for the saponin fraction of their water extracts, i.e., the saponins with a sugar moiety at position 28 [achyranthosides B (3), C (4) and D (5)] were the major constituents, the saponins without sugar moiety at position 28 [betavulgarosides II (10) and IV (11)] were the major constituents, and mixtures of these saponins. In a decoction prepared from the sample which contained 10 and 11 as the major saponins, their amounts were largely decreased compared with those of the water extract. As large amounts of these saponins were found in the precipitates formed by heating of the water extract, these saponins were seemed to precipitate out under heating. When hot water was used for the extraction, 3, 4 and 5 were detected even from the samples whose water extract did not contain these saponins. This was attributed to inhibition of endogenous esterase which hydrolyzes the ester linkage at position 28. When saponins were extracted with reagent grade 1-butanol, in addition to the decrease of the amounts of highly polar saponins, oxidative decarboxylation of 3 and 10 occurred resulting in formation of achyranthoside E (6) and spinacoside D (12), respectively. As these changes were not observed with HPLC grade 1-butanol, which contain not more than 5ppm of peroxide impurities, the change was attributable to the peroxide impurities contained in the reagent grade 1-butanol.

An Efficient Purification Method for Quantitative Determinations of Protodioscin, Dioscin and Diosgenin in Plasma of Fenugreek-Fed Mice.

An efficient purification method for simultaneous recovery of polar saponins, protodioscin (PD) and dioscin (DC), and non-polar aglycon, diosgenin (DG), from plasma of mice fed diets containing seed flours of fenugreek (Trigonella foenum-graecum) was established for subsequent quantitative analysis by LC-ESI-MS/MS. Mice plasma samples were first deproteinated by addition of acetonitrile, and the supernatant was applied to a carbon-based solid phase extraction tube. After successive washing with methanol and 35% chroloform/methanol (v/v), PD, DC and DG were eluted simultaneously with 80% chroloform/methanol (v/v). The eluate was evaporated to dryness, and re-dissolved in 80% methanol (v/v). The filtered sample was analyzed with an LC-ESI-MS/MS system. After the purification procedure, recovery rates between 89.3 to 117.4% were obtained without notable ion suppression or enhancement. The use of internal standards was therefore not necessary. The utility of the method was demonstrated by analyzing plasma of mice from a fenugreek feeding study.

Drugs based on natural compounds: recent achievements and future perspectives

In recent years, despite enormous efforts to develop new drugs by sophisticated approaches, there has also been a trend for rediscovery of natural products uses. In this context, new metabolites with unusual chemical structures and promising biological and pharmacological properties have inspired chemists in their synthetic approach searching for more potent and selective drugs. At the same time, the increasing awareness on prevention of common diseases such as atherosclerosis and cancer suggested an improvement of life style, including better diets by consumption of natural foods. These topics have been the focus of the Conference on Natural Products in Cancer Prevention and Therapy, 2nd Edition, a meeting hosted by the University of Naples ‘‘Federico II’’ on behalf of the Phytochemical Society of Europe. As chairman of the organizing committee, I have been very honoured and pleased by the large participation of over 120 scientists from 25 countries, not limited to Europe, but including also Africa, America and Asia. The aim of the congress was the presentation of recent results and the exchange of ideas in the field of natural products in cancer prevention and therapy, but also the discussion of new trends and general aspects of research in phytochemistry and medicinal chemistry. Higher plants continue to be the source of many new drugs used for a variety of diseases. This important matter has been discussed by Kinghorn and co-workers involved in a collaborative multi-institutional project directed towards the discovery of new antitumor agents. In their paper, opening this special issue, the isolation and characterization of new secondary metabolites from tropical plants is described together with data regarding their activity and selectivity for cancer cells. Some of these natural product lead candidates, discovered through bioactivity guided fractionation, are proposed as scaffolds for synthetic modifications to develop new potential anticancer agents. The article by Roussis and co-workers reports on the analysis of 46 different Pinus species, affording the identification of 161 metabolites, mainly volatiles, from the pine foliage oils. The work is a representative example of traditional extensive phytochemical research consisting of a comparative metabolomic characterization of plants aimed to find new compounds of potential pharmaceutical interest. Recent epidemiological studies reported that an increase of consumptions of Allium species reduce the risk of prostate and gastric cancers. This could be related to two main classes of compounds: the apolar sulfur compounds and the polar saponins, the latter being pungent and more stable during cooking. On this base, the third contribution by Lanzotti et al. reviewed the literature about the major volatile and non-volatile organic compounds of garlic and other Allium plants V. Lanzotti (&) Dipartimento di Agraria, University of Naples Federico II, Via Universita 100, 80055 Portici, Naples, Italy e-mail: lanzotti@unina.it

Fractionated extraction of saponins from Brazilian ginseng by sequential process using supercritical CO2, ethanol and water

Saponins are surfactants that reduce the surface tension of aqueous solutions, besides having pharmacological actions. In order to extract and fractionate saponins from Pfaffia glomerata roots and Hebanthe eriantha roots using supercritical technology, fractionated extracts were obtained from a sequential process in fixed bed using supercritical CO2 (scCO2), ethanol, and water as solvents. All extractions were carried out in four sequential steps, at 50°C and 300bar. In the first step, pure scCO2 was used as solvent, while (a) scCO2/etanol (70:30, w/w); (b) ethanol, and (c) ethanol/water (70:30, v/v) were used as solvents in the three subsequent steps. The extracts were analyzed by thin layer chromatography (TLC) and surface tension. The extraction yields of the four steps were 0.16, 0.55, 1.00, and 6.90% for P. glomerata roots, and 0.17, 0.58, 0.89, and 28% for H. eriantha roots, showing a predominance of high polarity compounds in these species. TLC analysis showed that the extraction process was selective according to the polarity of the solvent, and provided extracts containing different saponins, except for scCO2 extraction. The extracts from the extraction using ethanol+scCO2 (Step 2) showed the greatest ability to reduce the surface tension of water from 72mNm−1 (pure water) to 25mNm−1, suggesting that this step was the best for extraction of less polar saponins in the extracts. The critical micelle concentration (CMC) values were approximately 2 and 8gL−1 for P. glomerata and H. Eriantha, respectively. These results confirmed the efficacy of the extraction process under study.

Compounds from Allium species with cytotoxic and antimicrobial activity

Garlic (Allium sativum L.) is a bulb-shaped plant belonging to the Allium genus which also includes onions (Allium cepa L.), leek (Allium ampeloprasum L. var. porrum Gay), shallot (Allium ascalonicum L), scallion (A. fistulosum L.) and chives (Allium schoenoprasum L.). The biological activity of garlic has been known since ancient times. Babylonians, Egyptians, Phoenicians, Greeks and Romans used garlic as a remedy for intestinal disorders, respiratory infections, skin diseases, bacterial infections, worms, wounds and tumors. In particular, before the discovery of antibiotics, garlic has been used against amoebic dysentery and epidemic diseases such as typhus, cholera, diphtheria, and tuberculosis. To date, more than 3,000 publications scientifically supported the use of garlic in the ethno-medicine. But what makes garlic and Allium species effective against cancer? The effect of garlic may arise from its antibacterial properties or from its ability to block formation on cancer-causing substances, half the activation of cancer causing substances, enhance DNA repair, reduce cell proliferation or induce cell death. Epidemiological studies have found that an increase of consumptions of Allium spp. reduce the risk of prostate and gastric cancers and this has been mainly related to two main classes of compounds: the apolar sulphur compounds and the polar saponins. These latter compounds, compared to the more studied thiosulphinates, have the advantages of not being pungent and more stable during cooking. Recently, there has been increasing scientific attention given to such compounds. In this paper, the literature about the major volatile and non-volatile organic compounds of garlic and other Allium plants has been reviewed. Particular attention is given to the compounds possessing antibacterial and cytotoxic activity in garlic and in the other Allium species and their mechanism of action.

Saponin Inventory from Argania spinosa Kernel Cakes by Liquid Chromatography and Mass Spectrometry

Argania spinosa kernel cakes, obtained from argan oil extraction process, are known to contain large amounts of saponins. Only a few have been characterised previously, due to the use of pure ethanol as extracting solvent. The use of aqueous 50% ethanol improved the extraction of more polar saponins. Identification of polar saponins in kernel cakes of Argania spinosa by liquid chromatography-mass spectrometry and NMR techniques. Defatted kernel cakes were first extracted with ethanol and then twice with 50% aqueous ethanol. Individual crude extracts were analysed with an ion-trap mass spectrometer in negative mode electrospray MS and MS/MS modes. NMR experiments were run under standard conditions at 300 K on a Bruker DRX-600 spectrometer. The LC-MS base peak chromatogram of saponins from pure ethanol extract was dominated by 11 large and several small peaks but the UV chromatogram showed only two peaks, corresponding to the main neutral saponins found previously in Argania: arganine A and B. In 50% aqueous ethanol extracts, numerous other saponins were detected. Many of them were glucuronide oleanane-type triterpene carboxylic acid 3,28-O-bidesmosides (GOTCAB saponins). The assignments of (1) H- and (13) C-NMR spectra of the four most abundant GOTCAB saponins confirmed the MS results. Four GOTCAB saponins were structurally identified by NMR analysis in the 50% aqueous ethanol extract. Furthermore, LC-MS analyses showed the presence of at least 19 additional polar saponins in these kernel cakes.

Application of Centrifugal Preparative Chromatography for the Isolation of Polar Triterpenene Saponins from Fagonia cretica

Application of Centrifugal Preparative Chromatography for the Isolation of Polar Triterpenene Saponins from Fagonia cretica

Ginsenoside compositions of Panax ginseng C.A. Meyer tissue culture and juice.

By TLC, DCC and HPLC analysis, ginsenoside compositions of ginseng tissue culture and juice showed distinct features of fresh materials by a high proportion of "polar saponins" and low panaxadiol/panaxatriol ratio.

Quantitative analysis of ginsenosides in fresh Panax ginseng.

TLC, DCC and HPLC were used to study the ginsenoside composition of the main root, lateral root, rhizome, leaves and seeds of Panax ginseng cultivated in Jilin, China. Each of these methods has advantages of its own and the ensemble reveal the special features of Jilin ginseng. Total saponin content of various plant parts in Jilin ginseng showed a mid-range value as compared to those in ginsengs reported in literature. Fresh as well as sun-dried specimens from the same batch possessed a high percentage of Rg1 in the main root and this might account for the traditional preference of this plant part despite its lowest percentage of saponin in the whole plant. Large amounts of polar saponins were also observed in roots and rhizome of fresh Jilin ginseng, the nature and significance of which remained to be investigated.