Cytotoxic steroidal saponins from the rhizomes of Paris fargesii var. Petiolata.

Phytochemical investigation on the rhizomes of Paris fargesii var. petiolata (Baker ex C. H. Wright) Wang et Tang led to the isolation of five previously undescribed steroidal saponins, parpetiosides A-E (1-5), and six known analogs (6-11). Their structures were established by extensive spectroscopic data analysis and chemical methods. Compound 5 was a rare steroidal saponin with disaccharide moiety linked at C-26 of dehydrokryptogenin that was hardly seen in the genus Paris. The cytotoxicities of the isolated compounds against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated, and compound 1 displayed certain inhibitory effect with IC50 values of 8.02 ± 0.45, 8.24 ± 0.57 and 6.20 ± 0.79 µM, respectively. Moreover, the preliminary mechanism of 1 inhibiting the proliferation of the three cancer cell lines might be related to cell cycle distribution and the induction of S phase arrest.

Cytotoxic Steroidal Saponins Containing a Rare Fructosyl from the Rhizomes of Paris polyphylla var. latifolia.

A phytochemical investigation of the steroidal saponins from the rhizomes of Paris polyohylla var. latifolia led to the discovery and characterization of three new spirostanol saponins, papolatiosides A-C (1-3), and nine known compounds (4-12). Their structures were established via extensive spectroscopic data analysis and chemical methods. Interestingly, compounds 1 and 2 possessed a fructosyl in their oligosaccharide moiety, which is rare in natural product and was firstly reported in family Melanthiaceae. The cytotoxicity of these saponins against several human cancer cell lines was evaluated by a CCK-8 experiment. As a result, compound 1 exhibited a significant cytotoxic effect on LN229, U251, Capan-2, HeLa, and HepG2 cancer cells with IC50 values of 4.18 ± 0.31, 3.85 ± 0.44, 3.26 ± 0.34, 3.30 ± 0.38 and 4.32 ± 0.51 µM, respectively. In addition, the result of flow cytometry analysis indicated that compound 1 could induce apoptosis of glioma cells LN229. The underlying mechanism was explored by network pharmacology and western bolt experiments, which indicated that compound 1 could induce glioma cells LN229 apoptosis by regulating the EGFR/PI3K/Akt/mTOR pathway.

CN-3 increases TMZ sensitivity and induces ROS-dependent apoptosis and autophagy in TMZ-resistance glioblastoma.

Many glioma patients develop resistance to temozolomide (TMZ) treatment, resulting in reduced efficacy and survival rates. TMZ-resistant cell lines SHG44R and U87R, which highly express O6 -methylguanine DNA methyltransferase (MGMT) and P-gp, were established. CN-3, a new asterosaponin, showed cytotoxic effects on TMZ-resistant cells in a dose- and time-dependent manner via reactive oxygen species (ROS)-mediated apoptosis and autophagy. Transmission electron microscopy and monodansylcadaverine (MDC) staining showed turgidity of the mitochondria and autophagosomes in CN-3-treated SHG44R and U87R cells. The autophagy inhibitor 3-methyladenine was used to confirm the important role of autophagy in CN-3 cytotoxicity in TMZ-resistant cells. The ROS scavenger N-acetyl- l-cysteine (NAC) attenuated the levels of ROS induced by CN-3 and, therefore, rescued the CN-3 cytotoxic effect on the viability of SHG44R and U87R cells by Cell Counting Kit-8 assays and JuLI-Stage videos. MDC staining also confirmed that NAC rescued an autophagosome increase in CN-3-treated SHG44R and U87R cells. Western blotting revealed that CN-3 increased Bax, cleaved-caspase 3, cytochrome C, PARP-1, LC3-Ⅱ, and Beclin1, and decreased P-AKT, Bcl-2, and p62. Further rescue experiments revealed that CN-3 induced apoptosis and autophagy through ROS-mediated cytochrome C, cleaved-caspase 3, Bcl-2, P-AKT, PARP-1, and LC3-Ⅱ. In addition, CN-3 promoted SHG44R and U87R cells sensitive to TMZ by reducing the expression of P-gp, MGMT, and nuclear factor kappa B p65, and it had a synergistic cytotoxic effect with TMZ. Moreover, CN-3 disrupted the natural cycle arrest and inhibited the migration of SHG44R and U87R cells by promoting cyclin E1 and D1, and by decreasing P21, P27, N-cadherin, ß-catenin, transforming growth factor beta 1, and Smad2.

A new sulfated triterpene glycoside from the sea cucumber Colochirus quadrangularis, and evaluation of its antifungal, antitumor and immunomodulatory activities.

Our continuing search for marine bioactive secondary metabolites led to the screening of crude extracts of sea cucumbers by the model of Pyricularia oryzae. A new sulfated triterpene glycoside, coloquadranoside A (1), together with four known triterpene glycosides, philinopside A, B, E and pentactaside B (2-5) were isolated from the sea cucumber Colochirus quadrangularis, and their structures were elucidated using extensive spectroscope analysis (ESI-MS, 1D and 2D NMR) and chemical methods. Coloquadranoside A possesses a 16-acetyloxy group in the holostane-type triterpene aglycone with a 7(8)-double bond, a double bond (25,26) at its side chain, and two ß-d-xylose in the carbohydrate chain. Coloquadranoside A exhibits in vitro some antifungus, considerable cytotoxicity (IC50 of 0.46-2.03 µM) against eight human tumor cell lines, in vivo antitumor, and immunomodulatory activity.

CN-3 induces mitochondrial apoptosis in glioma via Ros-mediated PI3K/AKT pathway.

Recently we isolated CN-3, a new asterosaponin from starfish Culcita novaeguineae, and reported that asterosaponin arrests glioma cell cycle via SCUBE3. However, the multiple mechanisms underlying CN-3 anti-glioma action remains poorly known. Thus, the focus of this study was to evaluate the inhibitory effect of CN-3 on human glioma cells and its underlying molecular mechanisms. U87 and U251 cells were incubated with various concentrations of CN-3, and CCK-8, transmission electron microscopy, ICELLigence, TUNEL, flow cytometry, N-acetyl-L-cysteine, and western blot were conducted. As a result, it was found that CN-3 significantly inhibited U87 and U251 cell viability and proliferation in a time- and dose- dependent manner, and also induced mitochondrial apoptosis. Furthermore, we detected that CN-3 downregulated PI3K, P-Akt, AKT and BCL-2, and upregulated cytochrome C and BAX in U87 and U251 cells. Moreover, ROS triggered the inhibition and cell apoptosis for CN-3 via inactivation of P-Akt and activation of cytochrome C. In conclusion, these findings suggest that CN-3 may be a promising candidate for the development of a therapy of glioma.

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.

New Cytotoxic Secondary Metabolites from Marine Bryozoan Cryptosula pallasiana.

A new sterol, (23R)-methoxycholest-5,24-dien-3ß-ol (1), two new ceramides, (2S,3R,4E,8E)-2-(tetradecanoylamino)-4,8-octadecadien-l,3-diol (6) and (2S,3R,2'R,4E,8E)-2-(tetradecanoylamino)-4,8-octadecadien-l,3,2'-triol (7), together with three known sterols (2-4), a lactone (5) and two ceramides (8,9), were isolated from the marine bryozoan Cryptosula pallasiana, collected at Huang Island of China. The structures of the new compounds were elucidated by extensive spectroscopic analyses, chemical methods and quantum electronic circular dichroism (ECD) calculations. Among the isolated compounds, sterol 1 possessed a rare side chain with a methoxy group at C-23, and a double bond between C-24 and C-25. Ceramides 6 and 7 possessed 14 carbons in their long-chain fatty acid base (FAB), which were different from the normal ceramides with 16 carbons in the FAB. Moreover, compounds 5 and 8 were isolated for the first time from marine bryozoans. Compounds 1-9 were evaluated for their cytotoxicity against human tumor cell lines HL-60, Hep-G2 and SGC-7901. The results showed that lactone 5 appears to have strong cytotoxicity against the test tumor cell lines, with IC50 values from 4.12 µM to 7.32 µM, and sterol 1 displayed moderate cytotoxicity with IC50 values between 12.34 µM and 18.37 µM, while ceramides 6-9 showed weak cytotoxicity with IC50 ranging from 21.13 µM to 58.15 µM.

A novel pregnane-type alkaloid from Pachysandra terminalis inhibits methicillin-resistant Staphylococcus aureus in vitro and in vivo.

A new kind of pregnane-type alkaloid, 20α-dimethylamino-3ß-senecioylamino-16ß-hydroxy-pregn-5-ene (K-6), was isolated from Pachysandra terminalis Sieb. et Zucc., and its antibacterial activity against MRSA and MRSE was evaluated. We found that K-6 showed antibacterial effects against MRSA and MRSE with minimum inhibitory concentration values (25 mg/L), but did not induce antibiotic resistance in bacteria easily. The administration of K-6 dose-dependently improved the animal survival rate of mice infected with MRSA, with survival rates of 36.34% and 66.67% in the low-dose and high-dose groups, respectively. The protective effects were associated with the reduction of the bacterial titers in the blood and with the morphological amelioration of infected tissues. Scanning and transmission electron microscopy analyses indicated that the cytoplasm shrink of bacterial cells led to noticeable gaps between the cell membrane and cell cytoplasm, and the severely damaged cell membrane resulted in leakage of intracellular content, which ultimately caused the lethal effect of K-6 on bacteria. These findings demonstrated that K-6 is a potential agent against MRSA and MRSE.

Two new triterpenoid saponins from the aerial parts of Anemone taipaiensis.

Phytochemical study on the aerial parts of Anemone taipaiensis for the first time led to the isolation of two new oleanane-type triterpenoid saponins 1 and 2, together with four known saponins (3-6). Their structures were elucidated by extensive spectroscopic analysis and chemical evidences. Saponins 2-4 exhibited cytotoxicity against human glioblastoma U251MG cell line with IC50 values ranging from 1.56 to 80.62 µM.

Triterpenoid saponins from the roots of Clematis argentilucida and their cytotoxic activity.

The reinvestigation of the n-BuOH extract of the roots of Clematis argentilucida led to the isolation of four new oleanane-type triterpenoid saponins, 1-4, four known saponins, 5-8, first isolated from the species, together with ten saponins, 9-18, reported in the preceding papers. The structures of saponins 1-8 were elucidated by extensive spectroscopic analysis and chemical evidences. The cytotoxicity of all the saponins were evaluated against human tumor HL-60, HepG-2, and SGC-7901 cell lines. The monodesmosidic saponins 4, 7, 8, and 14-18 exhibited cytotoxic activity against the three cell lines with IC50 values in the range of 0.87-19.48 µM.

Neritinaceramides A-E, new ceramides from the marine bryozoan Bugula neritina inhabiting South China Sea and their cytotoxicity.

Five new ceramides, neritinaceramides A (1), B (2), C (3), D (4) and E (5), together with six known ceramides (6-11), two known alkyl glycerylethers (12 and 13) and a known nucleoside (14), were isolated from marine bryozoan Bugula neritina, which inhabits the South China Sea. The structures of the new compounds were elucidated as (2S,3R,3'S,4E,8E,10E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,3'-triol (1), (2S,3R,2'R,4E,8E,10E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,2'-triol (2), (2S,3R,2'R,4E,8E,10E)-2-(octadecanoylamino)-4,8,10-octadecatriene-l,3,2'-triol (3), (2S,3R,3'S,4E,8E)-2-(hexadecanoylamino)-4,8-octadecadiene-l,3,3'-triol (4) and (2S,3R,3'S,4E)-2-(hexadecanoylamino)-4-octadecene-l,3,3'-triol (5) on the basis of extensive spectral analysis and chemical evidences. The characteristic C-3'S hydroxyl group in the fatty acid moiety in compounds 1, 4 and 5, was a novel structural feature of ceramides. The rare 4E,8E,10E-triene structure in the sphingoid base of compounds 1-3, was found from marine bryozoans for the first time. The new ceramides 1-5 were evaluated for their cytotoxicity against HepG2, NCI-H460 and SGC7901 tumor cell lines, and all of them exhibited selective cytotoxicity against HepG2 and SGC7901 cells with a range of IC50 values from 47.3 µM to 58.1 µM. These chemical and cytotoxic studies on the new neritinaceramides A-E (1-5) added to the chemical diversity of B. neritina and expanded our knowledge of the chemical modifications and biological activity of ceramides.

Two previously undescribed cholestanol saponins from the rhizomes of Paris fargesii var. petiolata.

Two previously undescribed cholestanol saponins, parpetiosides F - G (1-2), and six known analogs (3-8) were isolated from the rhizomes of Paris fargesii var. petiolata. Their structures were elucidated by extensive spectroscopic data analysis and chemical methods. Compound 1 was a rare 6/6/6/5/5 fused-rings cholestanol saponin with disaccharide moiety linked at C-26 of aglycone which was hardly seen in genus Paris. All of these compounds were discovered in this plant for the first time. In addition, the cytotoxicities of saponins (1-8) against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated by CCK-8 method, and saponins 5-8 displayed certain cytotoxicities. The strong interactions between saponins 5-8 and SCUBE3, an oncogene for glioma cells, were displayed by molecular docking.

Two new saponins from the rhizomes of Paris yunnanensis Franch.

The phytochemical investigation on the rhizomes of Paris yunnanensis Franch. resulted in the discovery and characterisation of six compounds, including two new saponins named parisyunnanosides M-N (1-2), and four known ones (3-6). The structures of isolated compounds were determined by spectroscopic data analysis and chemical methods. Compound 2 is a pregnane-type saponin with a special α,ß-unsaturated carboxylic acid moiety at C-17, which is first discovered in genus Paris. The anti-inflammatory activity of the isolated compounds was assessed in vitro. The results demonstrated that compounds 3 and 4 could significantly inhibit the production of NO which was induced by LPS in RAW 264.7 cells with IC50 values of 0.67 ± 0.17 µM and 0.85 ± 0.12 µM, respectively.

Bioactive oleanane-type saponins from the rhizomes of Anemone taipaiensis.

Investigation of the n-BuOH extract of the rhizomes of Anemone taipaiensis led to the isolation of five new oleanane-type triterpenoid saponins (1-5), together with seven known saponins (6-12). Their structures were determined by the extensive use of (1)D and (2)D NMR experiments along with ESIMS analyses and acid hydrolysis. The aglycone of 1, 2 and 4 was determined as siaresinolic acid, which was reported in this genus for the first time. The cytotoxicities of the saponins 1-12, prosapogenins 4a, 5a, 10a-12a and sapogenins siaresinolic acid (SA), oleanolic acid (OA), hederagenin (HE) were evaluated against five human cancer cell lines, including HepG2, HL-60, A549, HeLa and U87MG. The monodesmosidic saponins 6-8, 5a, 10a-12a and sapogenins SA, OA, HE exhibited cytotoxic activity toward all cancer cell lines, with IC50 values ranging from 2.25 to 57.28 µM. Remarkably, the bisdesmosidic saponins 1-4 and 9 showed selective cytotoxicity against the U87MG cells.

Triterpenoid saponins with anti-myocardial ischemia activity from the whole plants of Clematis tangutica.

Four new triterpenoid saponins named clematangosides A-D (1-4) along with six known saponins (5-10) were isolated from the whole plants of Clematis tangutica. Their structures were determined by extensive spectral analysis and chemical evidences. All saponins were evaluated for their protective effects in hypoxia-induced myocardial injury model. Compounds 2-4, 6, and 10 exhibited anti-myocardial ischemia activities with ED50 values in the range of 75.77-127.22 µM.

The alkaloids with neuroprotective effect from the root bark of Ailanthus altissima.

The chemical constituent investigation on the root bark of Ailanthus altissima leads to the isolation of a new ß-carboline alkaloid, 14(S),15-dihydroxy-6-methoxy-ß-carboline (1), along with nine known alkaloids. The structure of new compound was elucidated on basis of extensive spectroscopic analysis, especially two-dimensional (2D) NMR techniques and the absolute configuration of C-14 was determined by ECD calculation. The neuroprotective effect of the isolated compounds on PC12 cells against the serum deprivation injury was evaluated by MTT method. As a result, compound 7 revealed protective effect on PC12 cells and the cell survival rate was significantly increased.

New steroidal saponins from the roots of Paris verticillata.

Four new polyhydroxylated steroidal saponins, parisverticillatosides A-D (1-4), together with four known spirostanol saponins (5-8) were isolated from the roots of Paris verticillata. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical evidences. The discovery of the new compounds 1-4 extended the diversity and complexity of this spirostanol saponin family. The saponins 5 and 6 exhibited cytotoxicities against two human glioma cell lines.

Cytotoxic steroidal glycosides from the rhizomes of Paris polyphylla var. yunnanensis.

Paris polyphylla var. yunnanensis (Franch.) Hand.-Mazz. (Melanthiaceae), an important specie of the genus Paris, has long been in a traditional Chinese medicine (TCM) for a long time. This study aimed to isolate and identify the structures of bioactive saponins from the rhizomes of P. polyphylla var. yunnanensis and evaluate their cytotoxicity against BxPC-3, HepG2, U373 and SGC-7901 carcinoma cell lines. Seven previously undescribed and seven known saponins were identified, and Paris saponins VII (PSVII) showed significant cytotoxicity against the BxPC-3 cell line with IC50 values of 3.59 µM. Furthermore, flow cytometry, transmission electron microscopy and western-bolt analysis revealed that PSVII inhibited the proliferation of BxPC-3 cells and might be involved in inducing apoptosis and pyroptosis by activating caspase-3, -7 and caspase-1, respectively.

New triterpenoid saponins from the whole plants of Clematis heracleifolia.

Three new triterpenoid saponins, heracleifolianosides A-C (1-3), together with seven known compounds (4-10), were isolated from the whole plants of Clematis heracleifolia. Moreover, three new secondary saponins (1a, 2a and 3a), two known secondary metabolites (5a and 7a) were obtained by alkaline hydrolysis. Their structures were elucidated by extensive spectroscopic analysis and chemical evidences. The cytotoxicity of eight native saponins and five prosapogenins against human breast tumor MDA-MB-231 and gastric carcinoma SGC-7901 cell lines were evaluated by MTT method. Remarkably, the prosapogenin monodesmosidic saponin 7a showed significant cytotoxicity against MDA-MB-231 or SGC-7901 cell lines with IC50 values in the range of 6.05-6.32 µmol/L. It is suggested that it might be a feasible way to change the inactive bisdesmosic triterpenoid saponins to active monodesmosic saponins by a simple procedure of alkaline hydrolysis.

Two new polyhydroxylated steroidal glycosides from the starfish Culcita novaeguineae.

The chemical constituent investigation on the starfish Culcita novaeguineae resulted in the isolation of two new polyhydroxylated steroidal glycosides and two known ones. The new compounds were identified as (25S)-3-O-(2-O-methyl-ß-D-xylopyranosyl)-26-O-(ß-D-xylopyranosyl)-cholest-4-ene-3ß,6ß,7α,8,15α,16ß,26-heptaol (1) and (25S)-3-O-(2-O-methyl-ß-D-xylopyranosyl)-26-O-(ß-D-xylopyranosyl)-cholest-4,24(28)-diene-3ß,6ß,7α,8,15α,16ß,26-heptaol (2) and the known compounds were determined as linckosides I and H (3-4). The structures of the isolated compounds were elucidated on the basis of extensive spectroscopic studies and chemical evidence. In addition, the cytotoxicity of the two new compounds against human glioblastoma cell lines U87, U251 and SHG44 was evaluated by MTT method.