New Analogues of Amides and Quinolinones Produced by Streptomyces sp. YIM S01983.

Streptomide (1), a new amide analogue, streptomynone (2), a new quinolinone, and ten known compounds including three aliphatic acids (3-5), two amides (6-7), four cyclic dipeptides (8-11), and an adenosine (12) were isolated from the fermentation broth of Streptomyces sp. YIM S01983 isolated from a sediment sample collected in Bendong Village, Huadong Town, Chuxiong, China. Their structures were determined by analysis of the 1D/2D-NMR and HR-ESI-MS spectra. Compound 12 presented weak antimicrobial activities against Candida albicans and Aligenes faecalis (MIC=64 µg/mL). Compounds 7 and 12 showed weak cytotoxic activity against MHCC97H.

Antimicrobial and Cytotoxic Angucyclic Quinones from Actinomadura miaoliensis.

Eight new angucyclic quinones, miaosporones A to H (1-8), along with the previously described metabolites 8-hydroxy-3-methylbenz[a]anthraquinone (9), tetrangulol (10), 5,6-dihydro-1,8-dihydroxy-3-methybenz[a]anthracene-7,12-quinone (11), and SF2315A (12), were isolated from the terrestrial actinomycete Actinomadura miaoliensis TBRC 5172 obtained from sediment collected from the Huai Yang reservoir, Prachuap Khiri Khan Province, Thailand. The relative and absolute configurations of the new compounds were determined from analysis of NMR spectroscopic and X-ray crystallographic data. Miaosporone A exhibited antimalarial activity against Plasmodium falciparum K1 and antibacterial activity against Mycobacterium tuberculosis with respective IC50 values of 2.5 and 2.4 µM and displayed cytotoxic activities against both cancerous (MCF-7 and NCI-H187) and nonmalignant (Vero) cells.

Jorunnamycin A Suppresses Stem-Like Phenotypes and Sensitizes Cisplatin-Induced Apoptosis in Cancer Stem-Like Cell-Enriched Spheroids of Human Lung Cancer Cells.

It has been recognized that cancer stem-like cells (CSCs) in tumor tissue crucially contribute to therapeutic failure, resulting in a high mortality rate in lung cancer patients. Due to their stem-like features of self-renewal and tumor formation, CSCs can lead to drug resistance and tumor recurrence. Herein, the suppressive effect of jorunnamycin A, a bistetrahydroisoquinolinequinone isolated from Thai blue sponge Xestospongia sp., on cancer spheroid initiation and self-renewal in the CSCs of human lung cancer cells is revealed. The depletion of stemness transcription factors, including Nanog, Oct-4, and Sox2 in the lung CSC-enriched population treated with jorunnamycin A (0.5 µM), resulted from the activation of GSK-3ß and the consequent downregulation of ß-catenin. Interestingly, pretreatment with jorunnamycin A at 0.5 µM for 24 h considerably sensitized lung CSCs to cisplatin-induced apoptosis, as evidenced by upregulated p53 and decreased Bcl-2 in jorunnamycin A-pretreated CSC-enriched spheroids. Moreover, the combination treatment of jorunnamycin A (0.5 µM) and cisplatin (25 µM) also diminished CD133-overexpresssing cells presented in CSC-enriched spheroids. Thus, evidence on the regulatory functions of jorunnamycin A may facilitate the development of this marine-derived compound as a novel chemotherapy agent that targets CSCs in lung cancer treatment.

New limonoids and quinolone alkaloids with cytotoxic and anti-platelet aggregation activities from Evodia rutaecarpa (Juss.) Benth.

One new limonoid, named 19-hydroxy methyl isoobacunoate diosphenol (1); one new degraded limonoid, named 9α-methoxyl dictamdiol (9); two new quinolone alkaloids, 1-methyl-3-[(7E,9E,12Z)-7,9,12-pentadecadienyl]-4(1H)-quinolone (11) and 1-methyl-3-[(7E,9E,11E)-7,9,11-pentadecadienyl]-4(1H)-quinolone (12), along with eight known compounds, evodol (2), 7ß-acetoxy-5-epilimonin (3), rutaevine (4), 6ß-acetoxy-5-epilimonin (5), limonin (6), obacunone (7), clauemargine L (8), hiiranlactone E (10) were isolated from the fruits of Evodia rutaecarpa (Juss.) Benth.. Structures of the four new compounds were elucidated on the basis of extensive spectroscopic techniques, including 1D and 2D NMR techniques. Compounds 3, 5, 9, 11 and 12 showed obviously cytotoxic activity against six human tumor lines, while compounds 11, 12 displayed anti-platelet aggregation induced by ADP at 50 µM and 100 µM.

Enantiomeric resolution of quinolones on crown ether CSP: Thermodynamics, chiral discrimination mechanism and application in biological samples.

The enantiomers of quinolone racemates were resolved using chiral crown ether within 8 min. Thermodynamics data and modeling results were used to determine chiral recognition mechanism. The column used was (+)-Crownpack column (250 mm × 4.6 mm, 5 µm) with three mobile phases I: ACN:Water (80:20) + 10 mM H2SO4 and 10 mM CH3COONH4, II: ACN:Water (80:20) + 20 mM perchloric acid and III: EtOH:Water (80:20) + 20 mM perchloric acid. The flow rate of the mobile phases was 1.0 mL/min with UV detection at different wavelengths. The ranges of retention (k), separation (α), and resolution (Rs) factors were 1.00-5.40, 1.37-2.00 and 1.50-3.30. The tailing factor was 1.o for all peaks with 900-2325 as the number of theoretical plates were 8.0-10.0 and 32.4-22.1 µg. The difference in enthalpy, entropy and free energy varied in the range of -0.350 to -0.024, 18.74 × 10-4 to 3.94 × 10-4 and -0.918 to -0.143, respectively. The thermodynamic and docking results showed chiral discrimination due to physical forces of amnio group cations penetration into the chiral cavity of the chiral selector following hydrogen bindings. The binding energy of S-enantiomers was higher than R-enantiomers; confirming stronger binding of S-enantiomers with CSP than R-enantiomers. The described chiral-HPLC method was used for the analysis of the quinolone enantiomers in urine samples and the results were quite satisfactory. Therefore, the reported method may be used for the enantiomeric separation of quinolone enantiomers in urine samples.

Viridicatol Isolated from Deep-Sea Penicillium Griseofulvum Alleviates Anaphylaxis and Repairs the Intestinal Barrier in Mice by Suppressing Mast Cell Activation.

Viridicatol is a quinoline alkaloid isolated from the deep-sea-derived fungus Penicillium griseofulvum. The structure of viridicatol was unambiguously established by X-ray diffraction analysis. In this study, a mouse model of ovalbumin-induced food allergy and the rat basophil leukemia (RBL)-2H3 cell model were established to explore the anti-allergic properties of viridicatol. On the basis of the mouse model, we found viridicatol to alleviate the allergy symptoms; decrease the levels of specific immunoglobulin E, mast cell protease-1, histamine, and tumor necrosis factor-α; and promote the production of interleukin-10 in the serum. The treatment of viridicatol also downregulated the population of B cells and mast cells (MCs), as well as upregulated the population of regulatory T cells in the spleen. Moreover, viridicatol alleviated intestinal villi injury and inhibited the degranulation of intestinal MCs to promote intestinal barrier repair in mice. Furthermore, the accumulation of Ca2+ in RBL-2H3 cells was significantly suppressed by viridicatol, which could block the activation of MCs. Taken together, these data indicated that deep-sea viridicatol may represent a novel therapeutic for allergic diseases.

HPLC enantio-separation and chiral recognition mechanism of quinolones on vancomycin CSP.

A new HPLC method was developed for the enantio-separation and chiral recognition mechanism of quinolones (lomefloxacine, ofloxacine, primaquine and quinacrine) on Vancomycin CSP. The column used was Chirabiotic V column (150 × 4.6 mm, 5.0 µm) with two mobile phases i.e. (I) MeOH:ACN:H2O:TEA (50:30:20:0.1%) and (II) MeOH:ACN: H2O:TEA (70:10:20:0.1%) at 1.0 mL/minute flow rate with various UV detection. The values of retention, separation and resolution factors in a solvent system I were ranged from 2.20 to 5.05, 1.70 to 1.96 and 1.75 to 2.20 while these values were 1.93 to 6.85, 1.62 & 2.01 and 2.30 & 2.40 in solvent system II. The limits of detection and quantification were ranged from 8.0 to 10.5 µg and 24.4 to 33.5 µg. The resolution was controlled mainly by π-π interactions along with other forces like hydrogen bonding, van der Waal's forces, steric effects, etc. The determination of the chiral recognition mechanism may be beneficial to separate other racemates successfully. The method is fast precise and efficient and may be utilized to analyze enantiomers of the reported quinolones.

Alkaloids from the nearly ripe fruits of Evodia rutaecarpa and their bioactivities.

Two novel quinolone alkaloids (1 and 2) and two novel indole alkaloids (5 and 8), together with eleven known analogues, were isolated from the nearly ripe fruits of Evodia rutaecarpa. Their structures were determined by extensive spectroscopic data, including NMR, HRESIMS, and ECD. Additionally, the anti-tumor, hypoglycemic, and anti-bacterial activities of the isolated alkaloids were evaluated in vitro. Compound 5 as a new alkaloid displayed moderate inhibitory effect against four human cancer cell lines (MCF-7 IC50 = 30.7 µM, Hepg-2 IC50 = 65.2 µM, A549 IC50 = 39.1 µM, and SHSY-5Y IC50 = 24.7 µM), α-glucosidase (IC50 = 23.9 µM) and PTP1B (IC50 = 75.8 µM). Compound 11 showed better inhibitory effect against PTP1B (IC50 = 16.2 µM) compared with that of the positive control. Compounds 5, 13, and 14 showed moderate inhibitory effects against Bacillus cereus with MIC values of 50, 25, and 10 µM, respectively.

Prenylated quinolinone alkaloids and prenylated isoindolinone alkaloids from the fungus Aspergillus nidulans.

Two undescribed prenylated quinolinone alkaloids, aspoquinolones E and F, and three undescribed prenylated isoindolinone alkaloids aspernidines F-H, were isolated from the fungus Aspergillus nidulans. Their structures and configurations were elucidated based on spectroscopic analyses and ECD spectra. Aspoquinolones E and F possess a C10 moiety with an unusual 2,2,4-trimethyl-3oxa-bicyclo[3.1.0]hexane unit, and aspernidines F-H own a C15 side chain. These compounds were evaluated for cytotoxic activities against five human cancer cell lines, compounds 1 and 5 exhibited strong inhibitory activities against A-549 and SW-480 cells with IC50 values of 3.50 and 4.77 µM, respectively.

Polyketides and a Dihydroquinolone Alkaloid from a Marine-Derived Strain of the Fungus Metarhizium marquandii.

Three new natural products (1-3), including two butenolide derivatives (1 and 2) and one dihydroquinolone derivative (3), together with nine known natural products were isolated from a marine-derived strain of the fungus Metarhizium marquandii. The structures of the new compounds were unambiguously deduced by spectroscopic means including HRESIMS and 1D/2D NMR spectroscopy, ECD, VCD, OR measurements, and calculations. The absolute configuration of marqualide (1) was determined by a combination of modified Mosher's method with TDDFT-ECD calculations at different levels, which revealed the importance of intramolecular hydrogen bonding in determining the ECD features. The (3R,4R) absolute configuration of aflaquinolone I (3), determined by OR, ECD, and VCD calculations, was found to be opposite of the (3S,4S) absolute configuration of the related aflaquinolones A-G, suggesting that the fungus M. marquandii produces aflaquinolone I with a different configuration (chiral switching). The absolute configuration of the known natural product terrestric acid hydrate (4) was likewise determined for the first time in this study. TDDFT-ECD calculations allowed determination of the absolute configuration of its chirality center remote from the stereogenic unsaturated γ-lactone chromophore. ECD calculations aided by solvent models revealed the importance of intramolecular hydrogen bond networks in stabilizing conformers and determining relationships between ECD transitions and absolute configurations.

Jorunnamycin A from Xestospongia sp. Suppresses Epithelial to Mesenchymal Transition and Sensitizes Anoikis in Human Lung Cancer Cells.

Metastasis is a key driving force behind the high mortality rate associated with lung cancer. Herein, we report the first study revealing the antimetastasis activity of jorunnamycin A, a bistetrahydroisoquinolinequinone isolated from a Thai blue sponge Xestospongia sp. evidenced by its inhibition of epithelial to mesenchymal transition (EMT), sensitization of anoikis, and suppression of anchorage-independent survival in human lung cancer cells. Treatment with jorunnamycin A (0.05-0.5 µM) altered the expression of p53 and Bcl-2 family proteins, particularly causing the down-regulation of antiapoptosis Bcl-2 and Mcl-1 proteins. Under detachment conditions for 12 h, jorunnamycin A-treated cells exhibited diminution of pro-survival proteins p-Akt and p-Erk as well as the survival-promoting factor caveolin-1. Corresponding with the inhibition on the Akt and Erk pathway as well as activation of p53, there was an increase in the epithelial marker E-cadherin and a remarkable decrease of EMT markers and associated proteins including vimentin, snail, and claudin-1. As the loss of anchorage dependence is an important barrier to metastasis, the observed inhibitory effects of jorunnamycin A on the coordinating networks of EMT and anchorage-independent growth emphasize the potential development of jorunnamycin A as an effective agent against lung cancer metastasis.

Glycopentanolones A-D, four new geranylated quinolone alkaloids from Glycosmis pentaphylla.

The ethanolic extract obtained from the stems of Glycosmis pentaphylla was found to suppress antigen-mediated degranulation of rat basophilic leukemia (RBL-2H3) cells. Four new geranylated 2-quinolone alkaloids, named glycopentanolones A-D (1-4), and 12 known metabolites (5-16) were isolated from the ethanolic extract from the stems of G. pentaphylla using bioassay-guided fractionation. Their structures were elucidated by a combination of 1D and 2D NMR, and HRESI-MS. The inhibitory effects of the isolated constituents on ß-hexosaminidase release from RBL-2H3 cells were examined, and compounds 1, 5, 8 and 11 exhibited potent inhibitory activity with IC50 values between 0.05 and 4.28 µM.

Induction of Secondary Metabolites from the Marine-Derived Fungus Aspergillus versicolor through Co-cultivation with Bacillus subtilis.

A new cyclic pentapeptide, cotteslosin C (1: ), a new aflaquinolone, 22-epi-aflaquinolone B (3: ), and two new anthraquinones (9: and 10: ), along with thirty known compounds (2, 4:  - 8, 11:  - 34: ) were isolated from a co-culture of the sponge-associated fungus Aspergillus versicolor with Bacillus subtilis. The new metabolites were only detected in the co-culture extract, but not when the fungus was grown under axenic conditions. Furthermore, the co-culture extract exhibited an enhanced accumulation of the known constituents versicolorin B (14: ), averufin (16: ), and sterigmatocyctin (19: ) by factors of 1.5, 2.0, and 4.7, respectively, compared to the axenic fungal culture. The structures of the isolated compounds were elucidated on the basis of 1D and 2D NMR spectra and mass spectrometry as well as by comparison with literature data. The absolute configuration of compounds 3, 9: , and 10: was determined by ECD (electronic circular dichroism) analysis aided by TDDFT-ECD (time-dependent density functional theory electronic circular dichroism) calculations. Compounds 15, 18:  - 21: , and 26: exhibited strong to moderate cytotoxic activity against the mouse lymphoma cell line L5178Y, with IC50 values ranging from 2.0 to 21.2 µM, while compounds 14, 16, 31, 32: , and 33: displayed moderate inhibitory activities against several gram-positive bacteria, with MIC values ranging from 12.5 to 50 µM.

Chiral separation and modeling of quinolones on teicoplanin macrocyclic glycopeptide antibiotics CSP.

New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150 × 4.6 mm, 5.0 µm). Three mobile phases used were MeOH:ACN:Water:TEA (70:10:20:0.1%), (60:30:10:0.1%), and (50:30:20:0.1%). The flow rate of the mobile phases was 1.0 mL/min with UV detection at different wavelengths. The values of retention, resolution, and separation factors ranged from 1.5 to 6.0, 1.80 to 2.25, and 2.86 to 6.0, respectively. The limit of detection and quantification ranged from 4.0 to 12 ng and 40 to 52 ng, respectively. The modeling studies indicated strong interactions of R-enantiomers with teicoplanin chiral selector than S-enantiomers. The supra molecular mechanism of the chiral recognition was established by modeling and chromatographic studies. It was observed that hydrogen bondings and π-π interactions are the major forces for chiral separation. The present chiral HPLC method may be used for enantiomeric resolution of quinolones in any matrices.

Xanthones and Quinolones Derivatives Produced by the Deep-Sea-Derived Fungus Penicillium sp. SCSIO Ind16F01.

Chemical investigation of the fungus Penicillium sp. SCSIO Ind16F01 derived from deep-sea sediment sample afforded a new xanthone, 3,8-dihydroxy-2-methyl-9-oxoxanthene-4-carboxylic acid methyl ester (1) and a new chromone, coniochaetone J (2), together with three known xanthones, 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (3), 7,8-dihydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (4), 1,6,8-trihydroxy-3-(hydroxymethyl)anthraquinone (5), three known chromones, coniochaetone B (6), citrinolactones B (7), epiremisporine B (8), and four reported rare class of N-methyl quinolone lactams: quinolactacins B (9), C1 (10), and C2 (11), and quinolonimide (12). The structures of new compounds were determined by analysis of the NMR and MS spectroscopic data. Those isolated compounds were evaluated for their antiviral (EV71 and H3N2) and cytotoxic activities.

Identification of 4-phenylquinolin-2(1H)-one as a specific allosteric inhibitor of Akt.

Akt plays a major role in tumorigenesis and the development of specific Akt inhibitors as effective cancer therapeutics has been challenging. Here, we report the identification of a highly specific allosteric inhibitor of Akt through a FRET-based high-throughput screening, and characterization of its inhibitory mechanism. Out of 373,868 compounds screened, 4-phenylquinolin-2(1H)-one specifically decreased Akt phosphorylation at both T308 and S473, and inhibited Akt kinase activity (IC50 = 6 µM) and downstream signaling. 4-Phenylquinolin-2(1H)-one did not alter the activity of upstream kinases including PI3K, PDK1, and mTORC2 as well as closely related kinases that affect cell proliferation and survival such as SGK1, PKA, PKC, or ERK1/2. This compound inhibited the proliferation of cancer cells but displayed less toxicity compared to inhibitors of PI3K or mTOR. Kinase profiling efforts revealed that 4-phenylquinolin-2(1H)-one does not bind to the kinase active site of over 380 human kinases including Akt. However, 4-phenylquinolin-2(1H)-one interacted with the PH domain of Akt, apparently inducing a conformation that hinders S473 and T308 phosphorylation by mTORC2 and PDK1. In conclusion, we demonstrate that 4-phenylquinolin-2(1H)-one is an exquisitely selective Akt inhibitor with a distinctive molecular mechanism, and a promising lead compound for further optimization toward the development of novel cancer therapeutics.

A new quinolinone and its natural/artificial derivatives from a shark gill-derived fungus Penicillium polonicum AP2T1.

Four quinolinones (1-4; 1 is a new compound) were isolated from the static fermentation culture of a shark gill-derived fungus Penicillium polonicum AP2T1. In addition, five new quinolinone derivatives (5-9) and also 1 were obtained in a trimethylsilyldiazomethane-induced methylation reaction of 4. Their structures were elucidated by spectroscopic analyses. In bioassays, compounds 7 and 5 with lactim structures moderately inhibited the proliferation of human cancer cell line HCT116 (wild-type) with IC50-24 h of 8.4 µg/mL and 30.7 µg/mL, respectively; the other compounds displayed weaker inhibition. The p53 gene may play some role in their action as suggested by their much weakened activity towards p53-knockout HCT116 cell line. Besides, 6 and 8 exhibited moderate or weak toxicity to brine shrimp larvae, and 3, 4, 8 and 9 showed weak inhibition against Staphylococcus aureus. It is the first report on elucidation of new compounds with origin of shark-derived fungi.

Selective solid-phase extraction of artificial chemicals from milk samples using multiple-template surface molecularly imprinted polymers.

A novel multiple-template surface molecularly imprinted polymer (MTMIP) was synthesized using ofloxacin and 17ß-estradiol as templates and modified monodispersed poly(glycidylmethacrylate-co-ethylene dimethacrylate) (PGMA/EDMA ) beads as the support material. Static adsorption, solid-phase extraction and high-performance liquid chromatography were performed to investigate the adsorption properties and selective recognition characteristics of the polymer templates and their structural analogs. The maximum binding capacities of ofloxacin and 17ß-estradiol on the MTMIP were 9.0 and 6.6 mg/g, respectively. Compared with the corresponding nonimprinted polymer, the MTMIP exhibited a much higher adsorption performance and selectivity toward three quinolones and three estrogens, which are common drug residues in food. The MTMIP served as a simple and effective pretreatment method and could be successfully applied to the simultaneous analysis of multiple target components in complex samples. Furthermore, the MTMIP may find useful applications as a solid-phase absorbent in the simultaneous determination of trace quinolones and estrogens in milk samples, as the recoveries were in the range 77.6-98.0%.

Quinolone and indole alkaloids from the fruits of Euodia rutaecarpa and their cytotoxicity against two human cancer cell lines.

Four quinolone alkaloids (1-4) and three indole alkaloids (20-22), together with 30 known alkaloids (5-19, 23-37), were isolated from the fruits of Euodia rutaecarpa. Their structures were established by spectroscopic analyses. The in vitro cytotoxic activities of these alkaloids against leukaemia HL-60 and prostate cancer PC-3 cell lines were evaluated.

Inhibition of hepatitis C virus replication by chalepin and pseudane IX isolated from Ruta angustifolia leaves.

Hepatitis C virus (HCV) infection is highly prevalent among global populations, with an estimated number of infected patients being 170 million. Approximately 70-80% of patients acutely infected with HCV will progress to chronic liver disease, such as liver cirrhosis and hepatocellular carcinoma, which is a substantial cause of morbidity and mortality worldwide. New therapies for HCV infection have been developed, however, the therapeutic efficacies still need to be improved. Medicinal plants are promising sources for antivirals against HCV. A variety of plants have been tested and proven to be beneficial as antiviral drug candidates against HCV. In this study, we examined extracts, their subfractions and isolated compounds of Ruta angustifolia leaves for antiviral activities against HCV in cell culture. We isolated six compounds, chalepin, scopoletin, γ-fagarine, arborinine, kokusaginine and pseudane IX. Among them, chalepin and pseudane IX showed strong anti-HCV activities with 50% inhibitory concentration (IC50) of 1.7 ± 0.5 and 1.4 ± 0.2 µg/ml, respectively, without apparent cytotoxicity. Their anti-HCV activities were stronger than that of ribavirin (2.8 ± 0.4 µg/ml), which has been widely used for the treatment of HCV infection. Mode-of-action analyses revealed that chalepin and pseudane IX inhibited HCV at the post-entry step and decreased the levels of HCV RNA replication and viral protein synthesis. We also observed that arborinine, kokusaginine and γ-fagarine possessed moderate levels of anti-HCV activities with IC50 values being 6.4 ± 0.7, 6.4 ± 1.6 and 20.4 ± 0.4 µg/ml, respectively, whereas scopoletin did not exert significant anti-HCV activities at 30 µg/ml.