Isolation and Anticancer Progression Evaluation of the Chemical Constituents from Bridelia balansae Tutcher.

The dichloromethane extract of the roots of Bridelia balansae Tutcher (Phyllanthaceae) was found to show potential anticancer activity against HCT116 colorectal cancer cell. Our bioassay-guided phytochemical investigation of the roots of B. balansae led to the identification of 14 compounds including seven lignans (1-7), three phenylbenzene derivatives (8-10), two flavanone (11-12), and two triterpenoids (13-14). Among them, 4'-demethyl-4-deoxypodophyllotoxin (1) is the first aryltetralin lignan compound identified from this plant species. In addition, the stereochemistry of 1 was validated by X-ray crystallography for the first time, and its distinguished cytotoxic effect on HCT116 cells with an IC50 value at 20 nM was induced via an apoptosis induction mechanism. Compound 1 could also significantly decrease the migration rate of HCT116 cells, indicating its potential application against cancer metastasis. The western blot analysis showed that 1 has the potential to inhibit cell proliferation and metastasis. Treatment of 1 resulted in the downregulation of matrix metalloproteinases 2 (MMP2) and p-Akt, while p21 was upregulated. Collectively, the present study on the phytochemical and biological profile of B. balansae has determined the plant as a useful source to produce promising anticancer lead compounds.

Divergent syntheses of okaramines C, J, L, and S-U.

The total synthesis of six novel okaramines (C, J, L, and S-U) was accomplished with a precise synthesis scheme involving a few steps and a practical yield of 6.7%-23% was obtained. The significance of this study includes the design of a successful and convenient synthesis method for preparation of 3a-hydroxy-pyrrolo[2,3-b]-indole and C-7 prenylated l-tryptophan derivatives using a nucleophilic attack of cyclopropylazetoindoline and an aza-Claisen rearrangement of N-reverse-prenyl tryptophan, respectively.

Synthesis of Javanicunines A and B, 9-Deoxy-PF1233s A and B, and Absolute Configuration Establishment of Javanicunine B.

Javanicunines A-B and 9-deoxy-PF1233s A-B belong to a family of natural diketomorpholines with a unique isopropenyl group at C-10b or C-5a and a hydroxyl group at C-11a or C-10b. We herein reported the first total synthesis of javanicunines A-B and 9-deoxy-PF1233s A-B. Pivotal features of the synthesis included a nucleophilic substitution reaction, followed by a Davis' oxaziridine oxidation to assemble javanicunines A-B, and a chemoselective and stereoselective oxidation with Murray's reagent to install the requisite C-10b hydroxyl group in 9-deoxy-PF1233s A-B. The present synthesis also established the absolute configuration of javanicunine B.

[Chemical constituent analysis for seeds of Celosia argentea by UPLC-ESI-Q-TOF-MS].

This Paper aimed to analyze and identify the chemical constituents from the seeds of Celosia argentea by UPLC-ESI-Q-TOF-MS. The analysis was performed on an ACQUITY HSS T3 reverse phase column(2.1 mm ×100 mm, 1.8 µm). The mobile phase consisting of 0.1% formic acid acetonitrile and 0.1% aqueous formic acid was used for gradient elution, and the flow rate was 0.4 mL·min~(-1). Mass spectrometry was applied for the qualitative analysis under positive and negative ionization modes and ESI ion source. Data was analyzed by Masslynx 4.1 software, literatures in SciFinder database, and standards. A total of 49 compounds, including 14 triterpenoids, 17 flavonoids, 11 cyclic peptides, 2 phenols, 2 organic acids, and 3 steroids were putatively identified. Among them, 19 compounds were firstly reported from this species. In-depth chemical constituent analysis for the seeds of C. argentea were accomplished here, and the findings could lay a good foundation for its quality control and clarifying the material basis of its efficacy.

Concise Synthesis of Natural Phenylphenalenone Phytoalexins and a Regioisomer.

Concise total syntheses of the natural phytoalexins 2-hydroxy-8-(4-hydroxyphenyl)phenalen-1-one (1), 2-hydroxy-8-(3,4-dihydroxyphenyl)phenalen-1-one (2), and hydroxyanigorufone (4), together with regioisomer 3 are accomplished in 11 or 12 steps. The synthetic strategy features a Friedel-Crafts acylation to construct the 1H-phenalen-1-one tricyclic core followed by a Suzuki cross-coupling to obtain the target compounds.

Ruthenium-catalyzed alkylation of indoles with tertiary amines by oxidation of a sp3 C-H bond and Lewis acid catalysis.

Ruthenium porphyrins (particularly [Ru(2,6-Cl(2)tpp)CO]; tpp=tetraphenylporphinato) and RuCl(3) can act as oxidation and/or Lewis acid catalysts for direct C-3 alkylation of indoles, giving the desired products in high yields (up to 82% based on 60-95% substrate conversions). These ruthenium compounds catalyze oxidative coupling reactions of a wide variety of anilines and indoles bearing electron-withdrawing or electron-donating substituents with high regioselectivity when using tBuOOH as an oxidant, resulting in the alkylation of N-arylindoles to 3-{[(N-aryl-N-alkyl)amino]methyl}indoles (yield: up to 82%, conversion: up to 95%) and the alkylation of N-alkyl or N-H indoles to 3-[p-(dialkylamino)benzyl]indoles (yield: up to 73%, conversion: up to 92%). A tentative reaction mechanism involving two pathways is proposed: an iminium ion intermediate may be generated by oxidation of an sp(3) C-H bond of the alkylated aniline by an oxoruthenium species; this iminium ion could then either be trapped by an N-arylindole (pathway A) or converted to formaldehyde, allowing a subsequent three-component coupling reaction of the in situ generated formaldehyde with an N-alkylindole and an aniline in the presence of a Lewis acid catalyst (pathway B). The results of deuterium-labeling experiments are consistent with the alkylation of N-alkylindoles via pathway B. The relative reaction rates of [Ru(2,6-Cl(2)tpp)CO]-catalyzed oxidative coupling reactions of 4-X-substituted N,N-dimethylanilines with N-phenylindole (using tBuOOH as oxidant), determined through competition experiments, correlate linearly with the substituent constants sigma (R(2)=0.989), giving a rho value of -1.09. This rho value and the magnitudes of the intra- and intermolecular deuterium isotope effects (k(H)/k(D)) suggest that electron transfer most likely occurs during the initial stage of the oxidation of 4-X-substituted N,N-dimethylanilines. Ruthenium-catalyzed three-component reaction of N-alkyl/N-H indoles, paraformaldehyde, and anilines gave 3-[p-(dialkylamino)benzyl]indoles in up to 82% yield (conversion: up to 95%).

The Use of Naphthoquinones and Furano-naphthoquinones as Antiinvasive Agents.

BACKGROUND: Cancer is a leading cause of mortality in the world and metastasis is to blame. A number of naphthoquinones (NQs) have shown ability to reduce cancer stemness and metastatic potential. Furano-naphthoquinones (FNQs), which is a class of NQ characterized by the incorporation of an additional furan ring, have demonstrated improved anti-cancer potency as compared to the other classes of NQs. OBJECTIVE: In this study, the natural origins, synthetic routes and derivatives of migrastatic NQs were reviewed. The anti-invasive and anti-metastatic mechanisms of NQs and the more powerful FNQs in targeting cancer were also discussed. METHODS: The articles related to the anti-invasive mechanisms of NQs were comprehensively reviewed. The plant origins, synthetic routes and antitumor effects of more than 360 FNQs were also covered and presented according to their chemical structures. RESULTS: Anti-cancer NQs inhibit cancer invasion by acting on epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and signal transducer and activator of transcription 3 (STAT3) signaling. BBI608, a natural FNQ, has entered phases I and II clinical trials. It has been regarded as a potential candidate for new-generation lead compound acting directly on CSCs to overcome the problem of chemotherapy resistance. Apart from the plant-derived FNQs, there are a number of synthetic FNQs that were found to intervene in cancer invasion and metastasis. CONCLUSION: The anti-invasive mechanisms of NQs have been thoroughly studied. FNQs generally show higher anti-cancer activity than that of NQs. The mechanisms of action of FNQs are worth further investigation.

A novel curcumin analog binds to and activates TFEB in vitro and in vivo independent of MTOR inhibition.

Autophagy dysfunction is a common feature in neurodegenerative disorders characterized by accumulation of toxic protein aggregates. Increasing evidence has demonstrated that activation of TFEB (transcription factor EB), a master regulator of autophagy and lysosomal biogenesis, can ameliorate neurotoxicity and rescue neurodegeneration in animal models. Currently known TFEB activators are mainly inhibitors of MTOR (mechanistic target of rapamycin [serine/threonine kinase]), which, as a master regulator of cell growth and metabolism, is involved in a wide range of biological functions. Thus, the identification of TFEB modulators acting without inhibiting the MTOR pathway would be preferred and probably less deleterious to cells. In this study, a synthesized curcumin derivative termed C1 is identified as a novel MTOR-independent activator of TFEB. Compound C1 specifically binds to TFEB at the N terminus and promotes TFEB nuclear translocation without inhibiting MTOR activity. By activating TFEB, C1 enhances autophagy and lysosome biogenesis in vitro and in vivo. Collectively, compound C1 is an orally effective activator of TFEB and is a potential therapeutic agent for the treatment of neurodegenerative diseases.

A silver-promoted auto-tandem catalysis for the synthesis of multiply substituted tetrahydrocarbazoles.

Silver(I) triflate efficiently catalyzes the tandem reaction of acetylenic aldehydes with indoles to give highly substituted tetrahydrocarbazoles in high yields.

Design, synthesis and antifungal activities of novel pyrrole alkaloid analogs.

A series of novel analogs of pyrrole alkaloid were designed and synthesized by a facile method and their structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). The structure of compound 2a was identified by 2D NMR including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC) and H-H correlation spectrometry (H-H COSY) spectra. Their antifungal activities against five fungi were evaluated, and the results indicated that some of the title compounds showed moderate fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae and Physalospora piricola at the dosage of 50 µg mL(-1). Compound 2a and 3a exhibited good activities against P. piricola at low dosage.

Gold(I)-catalyzed enantioselective intermolecular hydroarylation of allenes with indoles and reaction mechanism by density functional theory calculations.

Chiral binuclear gold(I) phosphine complexes catalyze enantioselective intermolecular hydroarylation of allenes with indoles in high product yields (up to 90%) and with moderate enantioselectivities (up to 63% ee). Among the gold(I) complexes examined, better ee values were obtained with binuclear gold(I) complexes, which displayed intramolecular Au(I)-Au(I) interactions. The binuclear gold(I) complex 4c [(AuCl)(2)(L3)] with chiral biaryl phosphine ligand (S)-(-)-MeO-biphep (L3) is the most efficient catalyst and gives the best ee value of up to 63%. Substituents on the allene reactants have a slight effect on the enantioselectivity of the reaction. Electron-withdrawing groups on the indole substrates decrease the enantioselectivity of the reaction. The relative reaction rates of the hydroarylation of 4-X-substituted 1,3-diarylallenes with N-methylindole in the presence of catalyst 4c [(AuCl)(2)(L3)]/AgOTf [L3 = (S)-(-)-MeO-biphep], determined through competition experiments, correlate (r(2) = 0.996) with the substituent constants σ. The slope value is -2.30, revealing both the build-up of positive charge at the allene and electrophilic nature of the reactive Au(I) species. Two plausible reaction pathways were investigated by density functional theory calculations, one pathway involving intermolecular nucleophilic addition of free indole to aurated allene intermediate and another pathway involving intramolecular nucleophilic addition of aurated indole to allene via diaurated intermediate E2. Calculated results revealed that the reaction likely proceeds via the first pathway with a lower activation energy. The role of Au(I)-Au(I) interactions in affecting the enantioselectivity is discussed.

Synthesis and insecticidal activities of novel anthranilic diamides containing modified N-pyridylpyrazoles.

In order to look for novel insecticides targeting the ryanodine receptor, four new series of anthranilic diamides containing modified N-pyridylpyrazoles were designed and synthesized. All of the compounds were characterized and confirmed by (1)H NMR, (13)C NMR, and HRMS. The single crystal structure of 10c was determined by X-ray diffraction. Their insecticidal activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) indicated that most of the compounds showed moderate to high activities at the tested concentration, while compound 19 showed comparable higher activity at the concentration of 0.125 mg/L. The preliminary structure-activity relationship (SAR) was discussed.

Synthesis and fungicidal activity of novel aminophenazine-1-carboxylate derivatives.

A series of novel 6-aminophenazine-1-, 7-aminophenazine-1- and 8-aminophenazine-1-carboxylate derivatives were synthesized by a facile method, and their structures were characterized by (1)H NMR, (13)C NMR and high-resolution mass spectrometry. Some unexpected byproducts V-7b-V-8d were noticed and isolated, and their structures were identified by 2D NMR spectra including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (Hmbc) and H-H correlation spectrometry (H-H COSY) approach. Their fungicidal activities against five fungi were evaluated, which indicated that most of the title compounds showed low fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae, and Physalospora piricola at a dosage of 50 microg mL(-1), while compounds IV-6a and IV-6b exhibited excellent activities against P. piricola at that dosage. Compound IV-6a could be considered as a leading structure for further design of fungicides.

Design, synthesis, and fungicidal activity of novel analogues of pyrrolnitrin.

A series of novel analogues of pyrrolnitrin containing a thiophene moiety were designed and synthesized by a facile method, and their structures were characterized by (1)H nuclear magnetic resonance (NMR) and high-resolution mass spectrometry. The isomers IV-h and V-h were isolated, and their structures were identified by 2D NMR, including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), and nuclear Overhauser effect spectrometry (NOESY) spectra. Their fungicidal activities against five fungi were evaluated, and the results indicated that some of the title compounds showed excellent fungicidal activities in vitro against Alternaria solani , Gibberella zeae , Physalospora piricola , Fusarium omysporum , and Cercospora arachidicola at the dosage of 50 microg mL(-1). Some compounds shown moderate activity at low dosage. Compound V-h could be considered as a leading structure for further design of agricultural fungicides.

Gold(I)-catalyzed intermolecular hydroarylation of alkenes with indoles under thermal and microwave-assisted conditions.

An efficient method for intermolecular hydroarylation of aryl and aliphatic alkenes with indoles using a combination of [(PR(3))AuCl]/AgOTf as catalyst under thermal and microwave-assisted conditions has been developed. The gold(I)-catalyzed reactions of indoles with aryl alkenes were achieved in toluene at 85 degrees C over a reaction time of 1-3 h with 2 mol% of [(PR(3))AuCl]/AgOTf as catalyst. This method works for a variety of styrenes bearing electron-deficient, electron-rich, and sterically bulky substituents to give the corresponding products in good to high yields (60-95%). Under microwave irradiation, coupling of unactivated aliphatic alkenes with indoles gave the corresponding adducts in up to 90% yield. Selective hydroarylation of terminal C=C bond of conjugated dienes with indoles gave good product yields (62-81%). On the basis of deuterium-labeling experiments, a reaction mechanism involving nucleophilic attack of Au(I)-coordinated alkenes by indoles is proposed.

Antifungal saponins from Paris polyphylla Smith.

Three steroidal saponins, including one new and two known compounds, were isolated from the rhizomes of Paris polyphylla Smith. One- and two-dimensional NMR, LC-MS, and interpretation of hydrolytic cleavage experiments led to the identification of the structure of the new saponin as ( 25R)-spirost-5-ene-3 beta,17 alpha-diol (pennogenin) 3- O-{ O- alpha- L-rhamnopyranosyl-(1-->2)- O-[ O- beta-xylopyranosyl-(1-->5)- alpha- L-arabinofuranosyl-(1-->4)]- beta- D-glucopyranoside}. The isolated saponins were evaluated for their antifungal activity against Cladosporium cladosporioides and Candida species and showed comparable activity to chemicals used in some commercial products.