Saponins with highly hydroxylated oleanane-type aglycones from Silphium asteriscus L

Chemical constituents from the Saposhnikovia divaricata and their antiproliferative activity

Nine compounds were isolated and identified from ethanolic extracts of Saposhnikovia divaricata, including one new alkaloid (1), one new pentacyclic triterpenoid (9), and seven known alkaloids (2-8). Structural elucidation of compounds 1 and 9 was established by 1D and 2D NMR spectra referring to the literature, together with high-resolution mass spectrometric analysis. All compounds were evaluated for antiproliferative activity against two cancer cell lines (LN229, A549) in vitro. Compounds (1-9) showed no significant antiproliferative activity.

Triterpene glycosides from Silene odontopetala

Silene species are known for their use in traditional medicine in treating several diseases. To the authors' knowledge there is no report on the chemical composition of S. odontopetala. Therefore, the phytochemical investigation of the methanol extract of S. odontopetala was carried out, leading to the isolation of six undescribed oleanane-type glycosides along with the known saponin azukisaponin IV. Their structures were elucidated by the analysis of 1D and 2D-NMR experiments, along with mass spectrometry analysis. The cytotoxic activity of oleanane-type saponins was evaluated against a small panel of cancer cell lines, including PC-3 (prostate carcinoma cells), MCF-7 (breast cancer cells), A549 (alveolar basal carcinoma cells), and HeLa (cervical carcinoma cells). Furthermore, the activity of isolated compounds against a normal cell line HEK-293, used for assessing their cytotoxicity, was evaluated.

Plant triterpenoid saponins: biosynthesis, in vitro production, and pharmacological relevance

The saponins are a diverse class of natural products, with a broad scale distribution across different plant species. Chemically characterized as triterpenoid glycosides, they posses a 30C oxidosqualene precursor-based aglycone moiety (sapogenin), to which glycosyl residues are subsequently attached to yield the corresponding saponin. Based on the chemically distinct aglycone moieties, broadly, they are divided into triterpenoid saponins (dammaranes, ursanes, oleananes, lupanes, hopanes, etc.) and the sterol glycosides. This review aims to present in detail the biosynthesis patterns of the different aglycones from a common precursor and their glycosylation patterns to yield the functionally active glycoside. The review also presents recent advances in the pharmacological activities of these saponins, particularly as potent anti-neoplastic pharmacophores, antioxidants, or anti-viral/antibacterial agents. Since alternate production pedestals for these pharmacologically important triterpenes via cell and tissue cultures are an attractive option for their sustainable production, recent trends in the variety and scale of in vitro production of plant triterpenoids have also been discussed.

In depth LC-ESIMSn-guided phytochemical analysis of Ziziphus jujuba Mill. leaves

Ziziphus jujuba Mill. leaves are receiving a great attention for their ability to improve sleep, exerting beneficial effects for both the heart and the central nervous system. With the aim to obtain a comprehensive analysis of the specialised metabolites occurring in the leaves of Z. jujuba, a LC-ESI/(HR)Orbitrap/MS profile in negative ion mode of the methanol extract was carried out. The LC-MS profile guided the isolation of 42 compounds, of which the structures were elucidated by 1D and 2D-NMR experiments. Based on this approach, 2 previously unreported dammarane-type saponins have been characterized along with flavonoid derivatives, dammarane-type saponins and triterpenic acids. Dammarane-type saponins were tested for their cytotoxic activity against A549 and HeLa cancer cell lines. None of the tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number. This work provides a deep insight on the chemistry of the leaves of Z. jujuba and could be useful for further biological studies aimed at identifying phytochemicals contributing to the health benefits attributed to this herbal drug.

Optimization of Microwave-Assisted Extraction Saponins from Sapindus mukorossi Pericarps and an Evaluation of Their Inhibitory Activity on Xanthine Oxidase

A microwave-assisted extraction (MAE) method was applied to separate saponins from Sapindus mukorossi pericarps. The most important factors of the six extraction parameters were selected using Plackett–Burman designs; therefore, the further extraction procedure was optimized using the Box–Behnken designs; meanwhile, the optimum processing parameters and well-pleasing saponins extraction rate were inferred. The final operation conditions were the ethanol concentration of 40%, soaking time of 3 h, particle size of 80–100 meshes, extraction time of 13 min, solvent-solid ratio of 19 mL/g, and microwave power of 425 W. Based on the optimal extraction parameters, the extraction rate of the saponins by means of MAE technique reached 280.55 ± 6.81 mg/g, which exceeds yields acquired using conventional manners. Saponins from S. mukorossi have obvious xanthine oxidase inhibitory properties in vitro compared with allopurinol. The saponins displayed a type of competitive inhibition of xanthine oxidase. In conclusion, a MAE technique in association with a response surface design provides an efficient extraction tactics, which could sufficiently isolate saponins from S. mukorossi pericarps; further, this technique could be applied to the dissociation of other bioactive substances from plant sources. In addition, the saponins may be a promising alternative to conventional medicine to treat gout and other inflammation-associated disorders to mitigate the side effects of traditional drugs.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Improving the Vanillin-Sulphuric Acid Method for Quantifying Total Saponins

The colorimetric assay used for saponin quantification in plant extracts is subject to interference by common solvents used to extract the saponins from plant materials. Therefore, the degree of interference of ten common solvents was investigated. It was found that the presence of acetone, methanol and n-butanol in the reaction solution caused an intense darkening of the reaction solution in the absence of saponins, which likely could lead to erroneous saponin content values. Using aescin to construct standard curves with different solvents—such as water, ethanol, and methanol— also showed significant differences in the standard curves obtained, which led to different values when they were applied to quantify the saponin content of an ethanol extract from dried and powdered Gac (Momordica cochinchinensis Spreng) seed kernels. To improve the method, a solvent evaporation step was added prior to the colorisation reaction to prevent undesired solvent interference during the reaction step. Using this modified protocol for the aescin standard curve and the Gac seed kernel extract eliminated any solvent interference. Thus, this improved protocol is recommended for the quantification of the saponin content of plant extracts irrespective of which extraction solvent is used.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Triterpenoid Saponins from Anemone rivularis var. Flore-Minore and Their Anti-Proliferative Activity on HSC-T6 Cells

Five previously undescribed triterpenoid saponins (1–5), along with eight known ones (6–13), were isolated from the whole plants of Anemone rivularis var. flore-minore. Their structures were clarified by extensive spectroscopic data and chemical evidence. For the first time, the lupane-type saponins (3 and 12) were reported from the Anemone genus. The anti-proliferative activity of all isolated saponins was evaluated on hepatic stellate cells (HSC-T6). Saponins 12 and 13, which possess more monosaccharides than the others, displayed potent anti-proliferative activity, with IC₅₀ values of 18.21 and 15.56 μM, respectively.

Cytotoxic triterpenoid saponins from Clematis tangutica

Eight previously undescribed oleanane-type triterpenoid saponins, clematangoticosides A-H, together with eight known saponins, were isolated from the whole plants of Clematis tangutica (Maxim.) Korsh. Their structures were elucidated by extensive spectroscopic analysis, in combination with chemical methods (acid hydrolysis and mild alkaline hydrolysis). Clematangoticosides D-G were found to be unusual 23, 28-bidesmosidic glycosides. The cytotoxic activities of all of the isolated saponins were evaluated against the four human cancer cell lines SGC-7901, HepG2, HL-60 and U251MG. Clematoside S, sapindoside B, kalopanax saponin A, and koelreuteria saponin A exhibited cytotoxicity against all of the test cancer cell lines with IC50 values in the range of 1.88-27.20 μM, while clematangoticoside D and F showed selective cytotoxicity against SGC-7901 with IC50 values of 24.22 and 21.35 μM, respectively.

Unusual fernane and gammacerane glycosides from the aerial parts of Spergula fallax

The aerial parts of Spergula fallax afforded four glycosides (1-4) based on two new triterpene aglycones (1a and 2a), along with the known hopane glycoside succulentoside A. Compound 1 was identified as belonging to the fernane class, unusual migrated hopane triterpenoids, mainly isolated from ferns and only rarely from higher plants. Compounds 2-4 were assigned as gammacerane glycosides, having as aglycone a hydroxylated derivative of tetrahymanol. The structures of the isolated compounds 1-4 and their aglycones 1a and 2a obtained by acid hydrolysis were elucidated by spectroscopic data interpretation. The growth inhibitory activity of the isolated compounds and their aglycones was evaluated against the HeLa and DLD-1 cancer cell lines.