Rapid Discovery of Substances with Anticancer Potential from Marine Fungi Based on a One Strain-Many Compounds Strategy and UPLC-QTOF-MS.

The secondary metabolites of marine fungi with rich chemical diversity and biological activity are an important and exciting target for natural product research. This study aimed to investigate the fungal community in Quanzhou Bay, Fujian, and identified 28 strains of marine fungi. A total of 28 strains of marine fungi were screened for small-scale fermentation by the OSMAC (One Strain-Many Compounds) strategy, and 77 EtOAc crude extracts were obtained and assayed for cancer cell inhibition rate. A total of six strains of marine fungi (P-WZ-2, P-WZ-3-2, P-WZ-4, P-WZ-5, P56, and P341) with significant changes in cancer cell inhibition induced by the OSMAC strategy were analysed by UPLC-QTOF-MS. The ACD/MS Structure ID Suite software was used to predict the possible structures with inhibitory effects on cancer cells. A total of 23 compounds were identified, of which 10 compounds have been reported to have potential anticancer activity or cytotoxicity. In this study, the OSMAC strategy was combined with an untargeted metabolomics approach based on UPLC-QTOF-MS to efficiently analyse the effect of changes in culture conditions on anticancer potentials and to rapidly find active substances that inhibit cancer cell growth.

Total Synthesis and Target Identification of the Curcusone Diterpenes.

The curcusone natural products are complex diterpenes featuring a characteristic [6-7-5] tricyclic carbon skeleton similar to the daphnane and tigliane diterpenes. Among them, curcusones A-D demonstrated potent anticancer activity against a broad spectrum of human cancer cell lines. Prior to this study, no total synthesis of the curcusones was achieved and their anticancer mode of action remained unknown. Herein, we report our synthetic and chemoproteomics studies of the curcusone diterpenes which culminate in the first total synthesis of several curcusone natural products and identification of BRCA1-associated ATM activator 1 (BRAT1) as a cellular target. Our efficient synthesis is highly convergent, builds upon cheap and abundant starting materials, features a thermal [3,3]-sigmatropic rearrangement and a novel FeCl3-promoted cascade reaction to rapidly construct the critical cycloheptadienone core of the curcusones, and led us to complete the first total synthesis of curcusones A and B in only 9 steps, C and D in 10 steps, and dimericursone A in 12 steps. The chemical synthesis of dimericursone A from curcusones C and D provided direct evidence to support the proposed Diels-Alder dimerization and cheletropic elimination biosynthetic pathway. Using an alkyne-tagged probe molecule, BRAT1, an important but previously "undruggable" oncoprotein, was identified as a key cellular target via chemoproteomics. We further demonstrate for the first time that BRAT1 can be inhibited by curcusone D, resulting in impaired DNA damage response, reduced cancer cell migration, potentiated activity of the DNA damaging drug etoposide, and other phenotypes similar to BRAT1 knockdown.

The synthesis and cytotoxic activity of derivatives of 4ß-hydroxywithanolide E.

4ß-Hydroxywithanolide E, which can be obtained in large amounts from the Physalis genus, possessed anti-proliferative effects on a variety of human cancer cell lines. For discussing its anti-tumor structure-activity relationship, a series of 4ß-hydroxywithanolide E derivatives (1-17) were synthesized and evaluated for their antitumor activity in vitro towards acute promyelocytic leukemia NB4 cell line by the Alarma blue assay. Cytotoxicity data revealed that the enone structure and C-4 hydroxyl substituents of ring A, together with the side chain (C-20-C-28) play an important effect on the cytotoxicity.

Hydroxy-octadecenoic acids instead of phorbol esters are responsible for the Jatropha curcas kernel cake's toxicity.

The toxic kernel cake of Jatropha curcas (KCakeJ) is an emerging health and environmental concern. Although phorbol esters are widely recognized as the major toxin of KCakeJ, convincing evidence is absent. Here, we show that rather than phorbol esters an isomeric mixture of 11-hydroxy-9E-octadecenoic acid, 12-hydroxy-10E-octadecenoic acid and 12-hydroxy-10Z-octadecenoic acid (hydroxy-octadecenoic acids, molecular formula C18H34O3) is the major toxic component. The toxicities of hydroxy-octadecenoic acids on experimental animals, e.g. acute lethality, causing inflammation, pulmonary hemorrhage and thrombi, allergies, diarrhea and abortion, are consistent with those on human/animals caused by Jatropha seed and/or KCakeJ. The hydroxyl group and the double bond are essential for hydroxy-octadecenoic acids' toxicity. The main pathway of the toxicity mechanism includes down-regulating UCP3 gene expression, promoting ROS production, thus activating CD62P expression (platelet activation) and mast cell degranulation. The identification of the major toxin of KCakeJ lays a foundation for establishing an environmentally friendly Jatropha biofuel industry.

Physalis peruviana-Derived 4ß-Hydroxywithanolide E, a Novel Antagonist of Wnt Signaling, Inhibits Colorectal Cancer In Vitro and In Vivo.

Deregulation of the Wnt signaling pathway leads to colorectal cancer progression. Natural dietary compounds serve as promising candidates for development as chemopreventive agents by suppressing the Wnt/ß-catenin signaling pathway. Physalis peruviana-derived 4ßHWE showed a significant inhibitory activity with a calculated IC50 of 0.09 µΜ in a screening of novel inhibitors of Wnt signaling with the dual-luciferase reporter assay. This study investigated the anti-tumor effect of 4ßHWE and the potential Wnt signaling inhibitory mechanism. Both the western blot analysis and immunofluorescence assay showed that 4ßHWE promoted the phosphorylation and degradation of ß-catenin and the subsequent inhibition of its nuclear translocation to attenuate the endogenous Wnt target gene expression in colorectal cancer (CRC) cells. The cell viability assay indicated that 4ßHWE preferentially inhibited the proliferation of CRC compared with CCD-841-CoN, a normal human colonic epithelial cell line. 4ßHWE-mediated G0/G1 cell cycle arrest and apoptosis induction contributed to the suppression of the proliferation of CRC in the cell cycle and Annexin V-FITC/Propidium Iodide apoptosis analysis. Moreover, in vivo, 4ßHWE dramatically inhibited tumor growth in HCT116 xenografts by attenuating the Wnt/ß-catenin signaling pathway. In conclusion, our study suggested that 4ßHWE could be of potential use in anti-tumor agent development as a novel Wnt signaling inhibitor.

Two new farnesyl phenolic compounds with anti-inflammatory activities from Ganoderma duripora.

Ganoderma fungi have long been used as a famous traditional medicine and food in country of East Asia. In this work, two new farnesyl phenolic compounds, ganoduriporols A and B (1 and 2), were isolated from the fruiting bodies of Ganoderma duripora, and their structures were elucidated using various spectroscopic methods. Anti-inflammatory activities were assayed and evaluated for the two compounds. Ganoduriporols A and B exhibited dose-dependent anti-inflammatory effects in RAW 264.7 cells. Furthermore, ganoduriporol A was demonstrated to inhibit the production of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and prostaglandin E2 (PGE2) through the suppression of COX-2, MAPK and NF-κB signaling pathway in LPS-induced macrophage cells. These results suggested that these two new farnesyl phenolic compounds and the fruiting body of G. duripora could serve as anti-inflammatory agents for medicinal use or functional food.

Three new withanolides from the calyces of Nicandra physaloides.

Chemical investigation on ethyl acetate extract of the calyces of Nicandra physaloides resulted in the isolation of three new withanolides named as nicphysatone A (1), nicphysatone B (2), nicphysatone C (3), together with five known withanolides, nic 17 (4), nic 7 (5), nic 2 (6), withahisolide G (7) and nicaphysalin B (8). The structures were determined by comprehensive spectroscopic experiments. The discovery enriched the diversity of natural withanolides and could serve as scaffolds for the synthesis of more potent modified withanolides.

Withanolides from aerial parts of Nicandra physalodes.

Twenty withanolides, including previously unknown nicanlodes A-M, were isolated from aerial parts of Nicandra physalodes. Their structural elucidations were unambiguously achieved through interpretation of extensive spectroscopic data (NMR and HRMS) and by comparison with literature data. Nicanlodes A and B have an unusual aromatic amine moiety. The isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines.

Biflavone Ginkgetin, a Novel Wnt Inhibitor, Suppresses the Growth of Medulloblastoma.

Medulloblastoma (MB) is a form of malignant brain tumor that predominantly arises in infants and children, of which approximately 25 % is due to upregulation of canonical Wnt pathway with mainly mutations in CTNNB1. Therefore, Wnt inhibitors could offer rational therapeutic strategies and chemoprevention for this malignant cancer. In our present study, we undertook a screening for antagonists of Wnt signaling from 600 natural compounds, and identified Ginkgetin, a biflavone isolated from Cephalotaxus fortunei var. alpina. Ginkgetin inhibited Wnt pathway with an IC50 value around 5.92 µM and structure-activity relationship analysis suggested the methoxy group in Ginkgetin as a functional group. Biflavone Ginkgetin showed obvious cytotoxicity in Daoy and D283 MB cells. Cell cycle analysis by flow cytometry showed that Ginkgetin induced efficiently G2/M phase arrest in Daoy cells. Further mechanism studies showed that Ginkgetin reduced the expression of Wnt target genes, including Axin2, cyclinD1 and survivin in MB cells. The phosphorylation level of ß-catenin also decreased in a time- and concentration-dependent manner. Collectively, our data suggest that Ginkgetin is a novel inhibitor of Wnt signaling, and as such warrants further exploration as a promising anti-medulloblastoma candidate.

Three new limonoids from Azadirachta indica.

Three new limonoids, azadiraindins E-G (1-3, respectively), together with six known analogs, were isolated from the fresh fruit coats of Azadirachta indica. The structures of these compounds were elucidated by spectroscopic methods (IR, MS, HR-ESI-MS, 1D NMR, and 2D NMR).

One-step semisynthesis method of spirocurcasone and pyracurcasone from curcusones A and B.

High contents of curcusones A and B and trace amounts of spirocurcasone exist in the roots of Jatropha curcas. Here, a one-step semisynthesis method of spirocurcasone and pyracurcasone was built, not only resulted an increased yield of spirocurcasone but also produced pyracurcasone, which exhibited greater cytotoxicity compared to curcusones A and B. The plausible mechanism of the formation of pyracurcasone was proposed, and the proposed biogenetic origin for spirocurcasone by Taglialatela-Scafati was confirmed.

Characterization of diterpenoid glucosides in roasted puer coffee beans.

Five new diterpenoid glucosides, named mascaroside I (1), mascaroside II (2), paniculoside VI (3), cofaryloside I (4), and villanovane I (5), along with seven known ent-kaurane diterpenoid glucosides (6-12) were isolated from acetone extracts of the roasted coffee beans of Coffea arabica var. yunnanensis. Their structures were established by extensive spectroscopic analysis including 1D and 2D NMR (HSQC, HMBC, COSY, and ROESY) and by comparison with published data. Cytotoxicities evaluation of the isolates showed that they were inactive against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cells.

Cucurbitane-type triterpenoids from the stems and leaves of Momordica charantia.

Six new cucurbitane-type triterpenoids, karavilagenin F (1), karavilosides XII and XIII (2, 3), momordicines VI, VII, and VIII (4, 5 and 6), along with four known ones, 5ß,19-epoxy-25-methoxycucurbita-6,23-diene-3ß,19-diol (7), 5ß,19-epoxycucurbita-6, 23-diene-3ß,19,25-triol (8), kuguacin R (9), and (19R,23E)-5ß,19-epoxy-19-methoxycucurbita-6,23,25-trien-3ß-ol (10), were isolated from the stems and leaves of Momordica charantia L. Their chemical structures were elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, COSY, and ROESY), MS experiments, and CD spectrum. Compound 6 showed weak cytotoxicity against five human cancer cells lines with IC50 values of 14.3-20.5µmol/L.

Hepatoprotective effects of triterpenoids from Ganoderma cochlear.

Two novel trinorlanostanes, cochlates A and B (1 and 2), with a 3,4-seco-9,10-seco-9,19-cyclo skeleton, as well as six new triterpenoids, fornicatins D-F (3-5) and ganodercochlearins A-C (6-8), together with five known triterpenoids (9-13), were obtained from the fruiting bodies of Ganoderma cochlear. The structural elucidation was achieved by interpretation of spectroscopic data, and compounds 2 and 7a were further characterized by X-ray crystallographic analysis. Fornicatins A, D, and F (10, 3, and 5) and fredelin (13) lowered the ALT and AST levels in HepG2 cells treated with H2O2, suggesting that they could display in vivo hepatoprotective activities.

Cytotoxicity of naturally occurring rhamnofolane diterpenes from Jatropha curcas.

Twelve rhamnofolane diterpenoids, including curcusecons A-E with unusual seco-rhamnofolane skeletons, curcusones F-J, 4-epi-curcusone E, and 3-dehydroxy-2-epi-caniojane, together with seven known analogues, curcusones A-E, jatrogrossidione, and 2-epi-jatrogrossidione, were isolated from the roots of Jatropha curcas. Their structures were determined by extensive spectroscopic methods, and the relative stereochemistry of curcusecon B was further confirmed by X-ray crystallographic data. Their cytotoxity against five human cancer cells was studied and the results indicated that the dienone system in ring B was essential for cytotoxicity of these compounds.

New eudesmenoic acid methyl esters from the seed oil of Jatropha curcas.

Three new eudesmenoic acid methyl esters (1-3), as well as five known compounds, including three germacranolides (4-6) and two eudesmanolides (7 and 8), were isolated from the seed oil of Jatropha curcas. The new compounds were elucidated by means of spectroscopic methods, including extensive NMR spectra. In addition, the structure of 8 was confirmed by a single-crystal X-ray diffraction analysis. Among the isolates, compounds 4-6 were the first reported from the genus Jatropha. Using MTS viability assay, the cytotoxicity of compounds 2-8 were evaluated against HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines. Compounds 4 and 5 showed remarkable cytotoxicity against all the tested cell lines with IC50 values from 0.5 to 3.5 µM, and the new compound 3 displayed selective cytotoxic activity against A-549 cell with an IC50 value of 7.24 µM, but slight cytotoxicity against HL-60 and MCF-7 with IC50 values of 23.77 and 22.37 µM, respectively.

Protective effects of triterpenoids from Ganoderma resinaceum on H2O2-induced toxicity in HepG2 cells.

Ganoderma resinaceum Boud. (Polyporeseae) has long been used for antioxidant, immunoregulation and liver protection. From the fruiting bodies of G. resinaceum, eight new lanostanoids, lucidones D-G (1-4), 7-oxo-ganoderic acid Z2 (5), 7-oxo-ganoderic acid Z3 (6), ganoderesin A (7), and ganoderesin B (8), together with six known lanostanoids (9-14) were isolated. The structures of new compounds were elucidated through extensive spectroscopic analysis. In an in vitro model, ganoderesin B (8), ganoderol B (10) and lucidone A (11) showed inhibitory effects against the increase of ALT and AST levels in HepG2 cells induced by H2O2 compared to a control group in the range of their maximum non-toxic concentration (MNTC). However, compounds 8, 10 and 11 displayed no anti-oxidant activities by DPPH assay. Meanwhile, activation for PXR (Pregnane X Receptor) of ganoderesin B (8), ganoderol B (10) and lucidone A (11) was evaluated; ganoderol (10) exhibited a vital activation for PXR-induced CYP3A4 expression. These results suggested that GTs (Ganoderma triterpenoids) exhibited hepatoprotective activities by lowering ALT and AST levels.

Limonoids from the leaves of Toona ciliata var. yunnanensis.

Twelve limonoids, toonayunnanins A-L (1-12) and eleven known compounds (13-23) were isolated from the leaves of Toona ciliata var. yunnanensis, and their structures were elucidated by means of extensive spectroscopic analyses, particularly 1D and 2D NMR techniques. The inhibitory effects of all the isolated compounds were evaluated on human tumor cell lines, such as HL-60, SMMC-7721, A-549, MCF-7 and SW480. Cedrelone (13) and dysobinin (18) showed significant cytotoxicity, and toonayunnanin B (2) and epoxyazadiradione (14), were found to be slightly cytotoxic against the above cell lines. Furthermore, this study provides valuable information for the chemotaxonomy of T. ciliata varieties.

Isolation and bioactivity evaluation of terpenoids from the medicinal fungus Ganoderma sinense.

A new pentanorlanostane, ganosineniol A (1), eight new lanostane triterpenoids, ganosinoside A (2), ganoderic acid Jc (3), ganoderic acid Jd (4), ganodermatetraol (5), ganolucidic acid γa (6), ganolucidate F (7), ganoderiol J ( 8), and methyl lucidenate Ha ( 9), and a new sesquiterpenoid, ganosinensine (10), together with eleven known triterpenoids (11- 21), were isolated from the fruiting bodies of the fungus Ganoderma sinense. Chemical structures were determined based on spectroscopic evidence, including 1D, 2D NMR, and mass spectral data. Furthermore, all isolates were tested for cytotoxic activity and induction ability of hPXR-mediated CYP3A4 expression. Among them, ganoderic acid Jc (3) displayed selective inhibitory activity against HL-60 cells (IC50 = 8.30 µM), and ganoderiol E (11) exhibited selective cytotoxic activity against MCF-7 cells (IC50 = 6.35 µM). Meanwhile, compounds 5, 7, and ganolucidic acids B and C (19, 20) showed induction ability of hPXR-mediated CYP3A4 expression.

One new pregnane glycoside from the seeds of cultivated Brucea javanica.

A new pregnane glycoside, named (20R)-O-(3)-ß-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl-pregn-5-en-3ß,20-diol (1), and seven known compounds, brusatol (2), bruceine B (3), bruceine D (4), yadanziolide A (5), bruceine E (6), yadanzioside G (7), and yadanzioside B (8), were isolated from the cultivated dry seeds of Brucea javanica. The structure of 1 was elucidated on the basis of 1D- and 2D-NMR spectroscopic analyses. Their inhibitory effects on tumor cells were also tested. Compound 1 was slightly active against HL-60, SMMC-7721, A-549, and MCF-7 tumor cells. Compounds 2 and 3 demonstrated significant inhibitory activities against all tested cells. These results indicate that cultivated B. javanica could replace the wild plant as an antitumor plant resource.