Cytotoxic and anti-inflammatory diterpenoids from the Dongsha Atoll soft coral Sinularia flexibilis

Seven new diterpenoids, namely, flexibilisolides C–G (1–5), flexibilisin C (6), and a novel 11,12-secoflexibillin (7), along with seven known compounds, 8–14, were isolated from the Dongsha Atoll soft coral Sinularia flexibilis. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and comparison of the NMR data with those of known analogues. Compounds 1, 8, and 11 were shown to exhibit moderate cytotoxic activity against HeLa and B16 cancer cell lines, and compound 10 was found to exhibit more potent cytotoxic activity against SK-Hep1 and B16 cancer cell lines. Moreover, compounds 1, 2, 8, 9, and 11–14 could significantly inhibit the accumulation of the pro-inflammatory iNOS protein and 1, 8, 11, and 14 could reduce the accumulation of COX-2 protein in LPS-stimulated RAW264.7 macrophage cells.     

Terpenoids with potent antimycobacterial activity against Mycobacterium tuberculosis from Trigonostemon reidioides roots

Phytochemical investigation of Trigonostemon reidioides roots led to the isolation of fourteen compounds. These included six new diterpenoids, trigonoreidons A?F (1?6), together with eight known diterpenoids 7?14. The structures of the new compounds were elucidated by spectroscopic techniques and the absolute configuration at the asymmetric carbon was determined by the modified Mosher's method. The structure of trigonoreidon B (2) was confirmed by X-ray crystallographic analysis. The known compounds were identified by comparison of the spectroscopic and physical data with those of reported values. The isolated compounds were evaluated for antimycobacterial activity against Mycobacterium tuberculosis. Among the compounds that exhibited antimycobacterial activity, the diterpenoids rediocide C (12) and rediocide G (14) were the most active compounds, with the MIC value of 3.84 μM.     

CAN catalyzed one-pot synthesis and docking study of some novel substituted imidazole coupled 1,2,4-triazole-5-carboxylic acids as antifungal agents

The present work describes a facile,one-pot three component synthesis of a series of 3-[(4,5-diphenyl-2-substituted aryl/heteryl)-1H-imidazol-1-yl]-1H-1,2,4-triazole-5-carboxylic acid derivatives M(1-15).Benzil,aromatic aldehydes and 3-amino-l,2,4-triazole-5-carboxylic acid was refluxed in ethanol using cerric ammonium nitrate(CAN) as a catalyst to give the title compounds in good yields.The compounds were evaluated for their in vitro antifungal and antibacterial activity.Compounds M1,M9,and M15 were found to be equipotent against Candida albicans when compared with fluconazole.Compounds M2.M5,and M14 showed higher activity against Streptococcus pneumoniae.Escherichia coli and Streptococcus pyogenes,respectively,compared with ampicillin.Docking study of the newly synthesized compounds was performed,and the results showed good binding mode in the active sites of C albicans enzyme cytochrome P450 lanosterol 14α-demethylase.The results of in vitro antifungal activity and docking study showed that synthesized compounds had potential antifungal activity and can be further optimized and developed as a lead compound.     

Grayanane diterpenoids with diverse bioactivities from the roots of Pieris formosa

During our continuing study on the roots of Pieris formosa, twelve new grayanane diterpenoids (1–12), together with eight known compounds (13–20), were obtained. Their structures with absolute configurations were characterized by a series of spectroscopic methods and X-ray diffraction. Compounds 1, 2, 4–5, 7–8, 14, and 19 exhibited significant analgesic activity in an acetic acid-induced writhing test. In particular, 7 and 14 were found to be 5 times more potent than morphine in the acetic acid-induced writhing test model. Compounds 1, 4, 9, 13, and 18 showed antifeedant activity against Plutella xylostella at 0.5 mg/mL. Compound 4 exhibited a 38.3% inhibitory effect against the KCNQ2 potassium channel at a concentration of 10 μM.     

Stereoselective synthesis and anticancer activity of broussonetine analogues

The stereoselective synthesis of two broussonetine analogues 14·HCl and ent-14·HCl with differing stereochemistry of the polyhydroxylated pyrrolidine core and a simple C₁₃ alkyl fragment has been achieved. For their construction, the known oxazolidinones 15 and 16 were chosen as appropriate advanced scaffolds. The common hydrophobic side chain was incorporated at an early stage of the synthesis through Grubbs’ cross metathesis chemistry. The required pyrrolidine skeleton was then formed by the cyclization of open chain intermediates 17 and 18. Four synthesized compounds were screened in vitro for antiproliferative/cytotoxic activity against six cancer cell lines by MTT assay. Compounds 14·HCl (HeLa and A-549) and ent-14·HCl (Caco-2 and Jurkat) showed comparable or higher potency than conventional anticancer agent cisplatin on at least two evaluated cancer cells, respectively.     

Antifouling and cytotoxic constituents from the South China Sea sponge Acanthella cavernosa

A bioassay-guided chemical investigation of the South China Sea sponge Acanthella cavernosa resulted in the isolation of eight new diterpenoids, kalihinols M–T (1–8), together with seven known analogues (9–15). These compounds featured a trans-decalin ring bearing a tetrahydrofuran or a tetrahydropyran ring at C-7. Compounds 1 and 2, with a formamide functionality beared at C-4, extended the structure breadth of this diterpenoid family. The absolute stereostructures of 1–14 were determined by a combination of 2D NMR and CD spectroscopic analysis and single crystal X-ray diffraction. Compounds 1 and 2 were confirmed to have the configurations of 4S, 5S, whereas 3–14 were determined as 4R, 5R. Compounds 3–14 displayed significant antifouling activity against the barnacle Balanus amphitrite larvae, and the cytotoxic activities of 3–14 were evaluated against the H1299, A549, PC3, CT-26, and HCT-116 cancer cell lines.     

Stereoselective synthesis and anti-HCV activity of conformationally restricted 2′-C-substituted carbanucleosides

Conformationally restricted 2′-C-azido-, hydroxy- and fluoromethyl-carbanucleosides 4b–f were efficiently synthesized via the stereoselective conversion of ketone 7 to epoxide 14, followed by the stereoselective opening of the epoxide with nucleophiles (OAc, N₃, and F), while the corresponding 2′-C-methyl-carbanucleoside 4a was synthesized via the stereoselective Grignard reaction of ketone 7 with methylmagnesium iodide as a key step. All the final nucleosides 4a–f were assayed for anti-HCV activity, but showed neither significant anti-HCV activity nor cytotoxicity in a cell-based replicon assay.     

New norditerpenoids and a diterpenoid from a sponge that inhibit the lyase activity of DNA polymerase β

Using an assay to detect inhibitors of the lyase activity of DNA polymerase β, bioassay-directed fractionation of a CHCl₃ extract of an unidentified sponge of the family Demospongiae resulted in the isolation of the new diterpenoid 1, the new bis-norditerpenoids 2-3, and the two known compounds spongia-13(16),14-dien-19-oic acid (4), and methylspongia-13(16),14-dien-19-oate (5). The structures of the new compounds were established on the basis of extensive 1D and 2D NMR spectroscopic interpretation. All five compounds inhibited the lyase activity of DNA polymerase β.     

Quinoline conjugated 2-azetidinone derivatives as prospective anti-breast cancer agents: In vitro antiproliferative and anti-EGFR activities,molecular docking and in-silico drug likeliness studies

Two series [1–8 (series-1) and 9–16 (series-2)] of quinoline conjugated 2-azetidinones were evaluated for their antiproliferative potential against breast cancer cell lines MCF7 and MDA-MB-231 respectively. All the compounds were more active towards against MCF7 than MDA-MB-231 cancer cell lines and few compounds activity was more than the standard erlotinib. For instance, the compound 16 of series-2 bearing electron withdrawing fluorine atom at the 6th position of quinoline ring showed promising activity with MIC values of 2.33 ± 0.19 µg/mL for MCF7 and 4.19 ± 0.22 µg/mL for MDA-MB-231 cells, respectively. In a similar way, the compounds 8 and 14 containing fluorine and chlorine substituents respectively, and located at position-6 of quinoline scaffold showed better activity than erlotinib. The ability of target compounds to inhibit EGFR tyrosine kinase, one of the key enzymes involved in breast carcinomas was evaluated by in vitro enzymatic assay and it was found that the compound 8 had close inhibitory activity to erlotinib with an %inhibition of 97.1 ± 0.08 at 10 µM. The compounds showed selective toxicity on the cancer cell lines as their IC₅₀ values are high against the human normal liver cell line-LO2. Further, the docking studies of the promising compounds 8, 14 and 16 revealed the important molecular interactions with the EGFR kinase enzyme (PDB ID: 6S9B). The physicochemical and pharmacokinetic properties of the most active compounds were predicted using Swiss ADME and pkCSM tools respectively. The most promising compounds arisen from the present study can be considered as prospective lead molecules for anticancer activity against breast carcinoma.     

New dibenzocyclooctadiene lignans from the Kadsura ananosma

Fourteen new dibenzocyclooctadiene lignans, ananonins A-N (1-14), together with five known compounds, were isolated from the seeds of Kadsura ananosma. The structures and absolute configurations of 1-14 were established using a combination of MS, NMR, and CD techniques. The biological activity of these compounds was evaluated, and ananonin M (13) showed moderate neuroprotective effects in an in vitro assay.     

Ferrocene-indole hybrids for cancer and malaria therapy

We report the synthesis, characterization, and cytotoxic and antimalarial activity of ferrocene-indole hybrids 8-14. The 2-phenylindole scaffold was chosen because of its potent antimitotic activity and ferrocene was chosen following the development of ferrocifens, ferrocene derivatives of tamoxifen, which are prototypes of a new family of organometallic anti-estrogens. Ferrocene-indole hybrids 8-14 and their corresponding organic analogues 1-7 showed only moderate antimalarial activities, while ferrocene-indole hybrids 11 and 12 showed excellent in vitro activities against the A549 human carcinoma cell line, with IC₅₀ values of 5 and 7 μM respectively. These ferrocene-indole hybrids were up to 25-fold more potent as cytotoxic agents than their purely organic analogues.     

New nitro-benzo[c]phenanthridine and indolopyridoquinazoline alkaloids from Zanthoxylum atchoum

The first phytochemical investigation of the roots of Zanthoxylum atchoum has led to the isolation of two new nitro-benzo[c]phenanthridine alkaloids 6-nitronitidine (1) and 6-nitro-8-methoxy-7,8-dihydronitidine (2), two new salts of indolopyridoquinazoline alkaloids 3-hydroxy-8,13-dihydro-14-methyl-5-oxo-7H-indolo[2’,3’:3,4]pyrido[2,1-b]quinazolin-14-ium (3) and its zwitterionic form 3-phenolate-8,13-dihydro-14-methyl-5-oxo-7H-indolo[2’,3’:3,4]pyrido[2,1-b]quinazolin-14-ium (4) along with 18 (5–22) known compounds. Their chemical structures were elucidated by spectroscopic analysis including 1D and 2D NMR and MS techniques. This is the first report of the nitro group on the biosynthesis of the natural benzo[c]phenantridine alkaloids. Compound 2 exhibited potent antibacterial activity against Staphylococcus aureus of MIC₅₀ = 4 μg·mL⁻¹.     

Chemoenzymatic synthesis of optically active α-methylene-γ-carboxy-γ-lactams and γ-lactones

Three α-methylene-γ-carbomethoxy-γ-butyrolactams (methyl α-methylene-pyroglutamates) 11, 12 and 13, differing in the substitution at the heterocyclic nitrogen, as well as the structurally related γ-lactones 14 and 15 were synthesised and resolved enzymatically by hydrolysis of their ester function, mediated by commercially available hydrolytic enzymes. In particular, the α-chymotrypsin proved to be active to all the substrates examined, displaying a different degree of activity and enantioselectivity, this latter increasing significantly towards the substrate with an aromatic substituent at the nitrogen.     

New mycotoxins from the scale insect fungus Aschersonia coffeae Henn. BCC 28712

Nine new mycotoxins; five xanthones 1–5, hydroxanthone 6, and three anthraquinones 7–9, together with nine known compounds; sterigmatocystin (10), demethylsterigmatocystin (11), dihydrodemethylsterigmatocystin (12), sterigmatin (13), austocystin F (14), averufin (15), aflatoxin B1, paeciloquinone A, and zeorin, were isolated from the scale insect fungus Aschersonia coffeae Henn. BCC 28712. The structures of these compounds were elucidated using NMR spectroscopic and MS spectrometric analyses. Compounds 1–3 and 6–9 displayed cytotoxic activity while the xanthone 2 and anthraquinones 8 and 9 also showed antimalarial activity.     

Transformations of hispanolone. Novel Michael adducts with in planta activity against rice blast

Two novel Michael adducts 9α-cyano-15,16-epoxy-7β-hydroxylabda-13(16),14-dien-6-one (2) and 9α-cyano-15,16-epoxy-7-hydroxylabda-7,13(16),14-trien-6-one (3) and the reduction product of 2, 9α-cyano-15,16-epoxy-6β,7β-dihydroxylabda-13(16),14-diene (4), were synthesized from the naturally occurring labdane diterpene hispanolone (1). Compounds 2-4 exhibited in planta activity against the pathogenic rice blast fungus Magnaporthe grisea.     

Derives 14-hydroxyles de la vincadifformine et de la vincamine

Hydroboration-oxidation of tabersonine 1 yielded as major product 14 β-hydroxy vincadifformine 9b, which was correlated with 14 β-hydroxy N(1)-methyl 2β-H, 16β-H dihydro vincadifformine 6b (previously prepared and characterised), and 14α-hydroxy vincadifformine 9a as minor product. The regio- and stereoselectivity of hydroboration-oxidation were interpreted. 9a and 9b were respectively oxidised and rearranged to the corresponding 14-hydroxy vincamines 13a and 13b. The coupling constants of H(14) on the NMR of the acetyl derivatives of 9a, 9b, 13a and 13b are consistent with an inversion of N(4) during the rearrangement leading from the vincadifformine to the vincamine skeleton.     

Pharmacophore-guided design, synthesis and evaluation of quinazoline-arylpiperazines as new α1-adrenoceptor antagonists

A series of arylpiperazinesquinazoline-2,4-diamine compounds were designed and synthesized based on pharmacophore for uro-selectiveα_1-adrenoceptor antagonists and 3D chemical database searching.The in vitro functional analysis showed that compounds 9 and 14 showed better and similarα_1-AR antagonistic activity compared with prazosin.     

Design,Synthesis, and Cytotoxicity of Semisynthetic Betulinic Acid-1,2,4-Oxadiazole Amide Derivatives

Biological activity of betulinic acid derivatives containing a 1,2,4-oxadiazole ring prompted us to synthesize betulinic acid-1,2,4-oxadiazole amide derivatives 14–25 starting with the amide coupling reaction of betulinic acid 1 and (3-aryl-1,2,4-oxadiazol-5-yl)methanamines 2–13. The products were tested for cytotoxicity on three human cancer cell lines in vitro. All tested compounds demonstrated high activity. The structures of the synthesized compounds were elucidated from IR, NMR and mass spectra.     

Blennolide derivatives from the soil-derived fungus Trichoderma asperellum PSU-PSF14

Three new blennolide derivatives, blennolides L-N (1–3), together with five known metabolites were isolated from the soil-derived fungus Trichoderma asperellum PSU-PSF14. Their structures were determined by analysis of spectroscopic data. Their relative configurations were determined by analysis of NOEDIFF data and confirmed by X-ray crystallography for compound 1 whereas the absolute configurations were established by means of experimental and calculated TDDFT ECD data. Compound 1 displayed antifungal activity against Cryptococcus neoformans ATCC90112 and ATCC90113 flucytosine-resistant with the MIC values of 128 and 64?μg/mL, respectively, and was inactive against noncancerous Vero cell lines.