Antiviral Merosesquiterpenoids Produced by the Antarctic Fungus Aspergillus ochraceopetaliformis SCSIO 05702.

Five new highly oxygenated α-pyrone merosesquiterpenoids, ochraceopones A-E (1-5), together with one new double bond isomer of asteltoxin, isoasteltoxin (6), and two known asteltoxin derivatives, asteltoxin (7) and asteltoxin B (8), were isolated from an Antarctic soil-derived fungus, Aspergillus ochraceopetaliformis SCSIO 05702. Their structures were determined through extensive spectroscopic analysis, CD spectra, quantum mechanical calculations, and X-ray single-crystal diffraction. Ochraceopones A-D (1-4) are the first examples of α-pyrone merosesquiterpenoids possessing a linear tetracyclic carbon skeleton, which has not been previously described. All the isolated compounds were tested for their antiviral, cytotoxic, antibacterial, and antitubercular activities. Among these compounds, ochraceopone A (1), isoasteltoxin (6), and asteltoxin (7) exhibited antiviral activities against the H1N1 and H3N2 influenza viruses with IC50 values of >20.0/12.2 ± 4.10, 0.23 ± 0.05/0.66 ± 0.09, and 0.54 ± 0.06/0.84 ± 0.02 µM, respectively. A possible biosynthetic pathway for ochraceopones A-E (1-5) was proposed.

Synthesis and biological evaluation of 3,5-disubstituted-4-alkynylisoxozales as a novel class of HSP90 inhibitors.

A series of 3,5-disubstitute-4-alkynylisoxazole derivatives were designed and synthesized through palladium(II)-copper(I) catalyzed Sonogashira cross-coupling reaction of an alkynyl moiety and an isoxazole scaffold as novel HSP90 inhibitors. The resultant compounds displayed moderate to potent binding affinity to HSP90 proteins, and also demonstrated good cell growth inhibitory activity against various cancer cell lines (A549, K562, MCF-7, DU145 and Hela). Some compounds (18d, 18e, 19a, 19d, 20c and 20q) show similar or better binding affinity towards HSP90α and HSP90ß comparing to NVP-AUY922. In addition, compounds 18e, 19a and 20q exhibited potent inhibitory activity against various human cancer cell lines.

Compounds from the insect Blaps japanensis with COX-1 and COX-2 inhibitory activities.

Blapsols A-D (1-4), four new compounds possessing a 2,3-dihydrobenzo[b][1,4]dioxin group, together with five known N-acetyldopamine dimers (5-9), were isolated from Blaps japanensis. Their structures including the absolute configuration of (+)-1 were determined by means of spectroscopic and X-ray crystallographic methods. Chiral HPLC was used to separate (-)- and (+)-enantiomers of compounds 1-4, which were isolated from this insect as racemic mixtures. All the compounds were found to have inhibitory effects towards COX-2 with IC50 values in the range of 1.3-17.8µM.

Asteltoxins with Antiviral Activities from the Marine Sponge-Derived Fungus Aspergillus sp. SCSIO XWS02F40.

Two new asteltoxins named asteltoxin E (2) and F (3), and a new chromone (4), together with four known compounds were isolated from a marine sponge-derived fungus, Aspergillus sp. SCSIO XWS02F40. The structures of the compounds (1-7) were determined by the extensive 1D- and 2D-NMR spectra, and HRESIMS spectrometry. All the compounds were tested for their antiviral (H1N1 and H3N2) activity. Compounds 2 and 3 showed significant activity against H3N2 with the prominent IC50 values of 6.2 ± 0.08 and 8.9 ± 0.3 µM, respectively. In addition, compound 2 also exhibited inhibitory activity against H1N1 with an IC50 value of 3.5 ± 1.3 µM.

Dihydrothiophene-condensed chromones from a marine-derived fungus Penicillium oxalicum and their structure-bioactivity relationship.

Four dihydrothiophene-condensed chromones including two new compounds oxalicumones D-E (1-2) and known oxalicumones A-B (3-4), along with five other known chromones were isolated from a culture broth of the marine gorgonian-associated fungus Penicillium oxalicum SCSGAF 0023. The structures of 1-2 were elucidated by spectroscopic analysis. Eleven derivatives 3a-3i and 4a-4b were obtained from the acylation of 3 and 4, respectively. Compounds 1-4, 3a-3e, 3g-3h, and 4b showed significant cytotoxicity against several carcinoma cell lines with IC50 ≤ 10 µM. And their structure-bioactivity relationship was discussed.

Graphene oxide based surface-enhanced Raman scattering probes for cancer cell imaging.

The intrinsic Raman signals provide the potential of graphene oxide (GO) for cellular imaging. Herein, novel surface-enhanced Raman scattering (SERS) labels based on GO-Ag nanoparticle (NP) composites are developed for fast cellular probing and imaging. The optimum SERS signals of the hybrids can be well controlled by adjusting the weight ratio between AgNO(3) and GO. Utilizing GO-AgNPs as the highly sensitive optical probes, fast SERS imaging of cancer cells is realized with a very short integration time of about 0.06 s per pixel. Furthermore, folic acid (FA) is covalently conjugated to GO for targeting specific cancer cells with folate receptors (FRs). Targeted SERS images can be acquired after 2 h incubation with FA-GO-AgNPs, which are specifically located on the surface of FR-positive cancer cells. In conclusion, the GO-based Raman probes mentioned here open up exciting opportunities for biomedical imaging.

[Green synthesis of silver nanoparticles and their application in SERS].

In the present paper, we have successfully synthesized silver nancomparticles by reducing of silver nitrate in alkaline solution via 60 degrees C water bath for 20 minutes with the use of tyrosine, a nontoxic and green macromolecule, as a reducing and stabilizing agent. The formation of silver nanoparticles was observed visually by color change of the solutions (from faint yellow to brown yellow). The morphologies of the Ag NPs were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). The UV-Vis absorption peak of silver nanoparticles located at 412 nm. The TEM image of silver nanoparticles indicated that the diameters of nanospheres are mainly in the range 15-25 nm. In order to evaluate the SERS activity of the silver nancomparticles, crystal violet and folic acid were used as the Raman probe molecule. The experimental results indicated that there are two ascendancies, firstly, the approach is convenient and the reaction condition is facile, secondly, tyrosine is a water-soluble, nontoxic and biodegradable macromolecule, which makes this approach provide a green strategy to prepare Ag NPs. Significantly, the synthesized Ag NPs exhibits good surface enhanced Raman scattering (SERS) activity as SERS substrates to detect crystal violet and folic acid in aqueous solution.

Pentafluorosulfanyl-Substituted Benzopyran Analogues As New Cyclooxygenase-2 Inhibitors with Excellent Pharmacokinetics and Efficacy in Blocking Inflammation.

In this report, we disclose the design and synthesis of a series of pentafluorosulfanyl (SF5) benzopyran derivatives as novel COX-2 inhibitors with improved pharmacokinetic and pharmacodynamic properties. The pentafluorosulfanyl compounds showed both potency and selectivity for COX-2 and demonstrated efficacy in several murine models of inflammation and pain. More interestingly, one of the compounds, R,S-3a, revealed exceptional efficacy in the adjuvant induced arthritis (AIA) model, achieving an ED50 as low as 0.094 mg/kg. In addition, the pharmacokinetics of compound R,S-3a in rat revealed a half-life in excess of 12 h and plasma drug concentrations well above its IC90 for up to 40 h. When R,S-3a was dosed just two times a week in the AIA model, efficacy was still maintained. Overall, drug R,S-3a and other analogues are suitable candidates that merit further investigation for the treatment of inflammation and pain as well as other diseases where COX-2 and PGE2 play a role in their etiology.

Quinone/hydroquinone meroterpenoids with antitubercular and cytotoxic activities produced by the sponge-derived fungus Gliomastix sp. ZSDS1-F7.

Fifteen compounds, including six quinone/hydroquinone meroterpenoids, purpurogemutantin (1), macrophorin A (2), 4'-oxomacrophorin (3), 7-deacetoxyyanuthone A (4), 2,3-hydro-deacetoxyyanuthone A (5), 22-deacetylyanuthone A (6), anicequol (7), three roquefortine derivatives, roquefortine C (8), (16S)-hydroxyroquefortine C (9), (16R)-hydroxyroquefortine C (10), dihydroresorcylide (11), nectriapyrone (12), together with three fatty acid derivatives, methyl linoleate (13), phospholipase A2 (14), methyl elaidate (15), were isolated from the sponge-derived fungus Gliomastix sp. ZSDS1-F7 isolated from the sponge Phakellia fusca Thiele collected in the Yongxing island of Xisha. Their structures were elucidated mainly by extensive NMR spectroscopic and mass spectrometric analyses. Among these compounds, compounds 1-3 and 5-7 showed significant in vitro cytotoxicities against the K562, MCF-7, Hela, DU145, U937, H1975, SGC-7901, A549, MOLT-4 and HL60 cell lines, with IC50 values ranging from 0.19 to 35.4 µM. And compounds 2-4 exhibited antitubercular activity with IC50 values of 22.1, 2.44 and 17.5 µM, respectively. Furthermore, compound 7 had anti-enterovirus 71 activity with MIC value of 17.8 µM. To the best of our knowledge, this is the first report to product two quinone/hydroquinone meroterpenoids skeletons (linear skeleton and drimane skeleton) from the same fungal strain.

Antituberculosis compounds from a deep-sea-derived fungus Aspergillus sp. SCSIO Ind09F01.

Eleven diketopiperazine and fumiquinazoline alkaloids (1-11) together with a tetracyclic triterpenoid helvolic acid (12) were obtained from the cultures of a deep-sea derived fungus Aspergillus sp. SCSIO Ind09F01. The structures of these compounds (1-12) were determined mainly by the extensive NMR, ESIMS spectra data and by comparison with previously described compounds. Besides, anti-tuberculosis, cytotoxic, antibacterial, COX-2 inhibitory and antiviral activities of these compounds were evaluated. Gliotoxin (3), 12,13-dihydroxy-fumitremorgin C (11) and helvolic acid (12) exhibited very strong anti-tuberculosis activity towards Mycobacterium tuberculosis with the prominent MIC50 values of <0.03, 2.41 and 0.894 µM, respectively, which was here reported for the first time. Meanwhile gliotoxin also displayed significant selective cytotoxicities against K562, A549 and Huh-7 cell lines with the IC50 values of 0.191, 0.015 and 95.4 µM, respectively.

Design, synthesis and cytotoxic activities of novel 2,5-diketopiperazine derivatives.

A series of novel N-1-monoallylated 2,5-diketopiperazine derivatives were designed, synthesized, and evaluated as cytotoxic agents against eight cancer cell lines by using CCK8 assay. These derivatives were substituted with methoxyphenyl groups at C-6 position, and various long alkyl side chains at C-3-position of the 2,5-diketopiperazine ring. The cytotoxic results showed that 4-methoxyphenyl group was better than 2-methoxyphenyl group as optimal substitutive group, while 3-methoxyphenyl group was not a suitable one. When the number (n value) of the methylene groups for the long alkyl side chain was 3 (compounds 1c and 3c), the derivatives had the strongest cytotoxicities. Compound 3c substituted with 4-methoxyphenyl group and pentylidene side chain exhibited strong activity (IC50 = 0.36-1.9 µM) against all cancer cell lines, and could obviously induce apoptosis of cancer cell line U937 at 1.0 µM after 48 h treatment.

Structure-Based Design of Potent Nicotinamide Phosphoribosyltransferase Inhibitors with Promising in Vitro and in Vivo Antitumor Activities.

Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) has the potential to directly limit NAD production in cancer cells and is an effective strategy for cancer treatment. Using a structure-based strategy, we have designed a new class of potent small-molecule inhibitors of NAMPT. Several designed compounds showed promising antiproliferative activities in vitro. (E)-N-(5-((4-(((2-(1H-Indol-3-yl)ethyl)(isopropyl)amino)methyl)phenyl)amino)pentyl)-3-(pyridin-3-yl)acrylamide, 30, bearing an indole moiety, has an IC50 of 25.3 nM for binding to the NAMPT protein and demonstrated promising inhibitory activities in the nanomolar range against several cancer cell lines (MCF-7 GI50 = 0.13 nM; MDA-MB-231 GI50 = 0.15 nM). Triple-negative breast cancer is the most malignant subtype of breast cancer with no effective targeted treatments currently available. Significant antitumor efficacy of compound 30 was achieved (TGI was 73.8%) in an orthotopic MDA-MB-231 triple-negative breast cancer xenograft tumor model. This paper reports promising lead molecules for the inhibition of NAMPT which could serve as a basis for further investigation.

New phenyl derivatives from endophytic fungus Botryosphaeria sp. SCSIO KcF6 derived of mangrove plant Kandelia candel.

Two new phenyl derivatives (1 and 3), along with two new natural products (4 and 5), and three known compounds (2, 6 and 7), were isolated from an endophytic fungus Botryosphaeria sp. SCSIO KcF6. The structures of these compounds 1-7 were elucidated by the extensive 1D and 2D-NMR and HRESIMS Data analysis, and compared with those of reported data. The absolute configuration of the compounds 1 and 3 were assigned by optical rotation and CD data. The isolated compounds were evaluated for their cytotoxic, anti-inflammatory (COX-2) and antimicrobial activities. Compound 3 exhibited a specific COX-2 inhibitory activity with the IC50 value of 1.12 µM.

Synthesis and Evaluation of Novel Erlotinib-NSAID Conjugates as More Comprehensive Anticancer Agents.

A series of novel anticancer agents were designed and synthesized based on coupling of different nonsteroidal anti-inflammatory drugs (NSAIDs) with the epidermal growth-factor receptor (EGFR) tyrosine kinase inhibitor, erlotinib. Both the antiproliferative and pharmacokinetic activity of the target compounds were evaluated using HCC827 and A431 tumor cell lines. Among the derivatives made, compounds 10a, 10c, and 21g showed superb potency, comparable to that of erlotinib. Furthermore, preliminary SAR analysis showed that when the NSAIDs were conjugated via linkage to C-6 OH versus linkage to C-7 OH of the quinazoline nucleus, superior anticancer activity was achieved. Finally, the in vitro pharmacokinetic profile of several conjugates demonstrated the desired dissociation kinetics as the coupled molecules were effectively hydrolyzed, releasing both erlotinib and the specific NSAID in a time-dependent manner. The conjugation strategy represents a unique and simplified approach toward combination therapy, particularly for the treatment of cancers where both EGFR overexpression and inflammation play a direct role in disease progression.

Sydoxanthone C and acremolin B produced by deep-sea-derived fungus Aspergillus sp. SCSIO Ind09F01.

A new xanthone named sydoxanthone C (1) and a new alkaloid named acremolin B (2), together with 10 known compounds (3-12) were isolated from a deep-sea-derived fungus Aspergillus sp. SCSIO Ind09F01. The structures of compounds (1-12) were determined by the extensive 1D, 2D-NMR, High resolution mass spectra (HRESIMS) data. Compounds 7, 8, 11 and 12 showed significant selective cytotoxicities against HeLa, DU145 and U937 cell lines. In addition, compounds 7, 8 and 11 also exhibited COX-2 inhibitory activities with the prominent IC50 values of 2.4, 7.1 and 10.6 µM, respectively.

Arthpyrones A-C, pyridone alkaloids from a sponge-derived fungus Arthrinium arundinis ZSDS1-F3.

Three new 4-hydroxy-2-pyridone alkaloids, arthpyrones A-C (1-3), were isolated from the sponge-derived fungus Arthrinium arundinis ZSDS1-F3. Their structures were elucidated on the basis of spectroscopic analysis, CD spectra, quantum chemical calculation, and X-ray single-crystal diffraction analysis. Compounds 1 and 2 possessed a 2-pyridone core featured with a decalin moiety linked via a carboxide bridge bearing a novel oxabicyclo[3.3.1]nonane ring system rarely discovered in nature. A possible biosynthetic pathway for them was proposed.

Tetramic acid derivatives and polyphenols from sponge-derived fungus and their biological evaluation.

Fifteen compounds, including two tetramic acid derivatives, penicillenol A1 (1) and penicillenol A2 (2), six polyphenols containing both phenolic bisabolane sesquiterpenoid and diphenyl ether units, expansols A-F (3-8), together with six phenolic bisabolane sesquiterpenoids (9-14) and diorcinol (15), were isolated from the fermentation broth of the marine-derived fungus ZSDS1-F11 isolated from the sponge Phakellia fusca Thiele collected in the Yongxing island of Xisha. Their structures were elucidated mainly by using extensive NMR spectroscopic and mass spectrometric analyses. Compounds 3-5, 7 and 8 showed potent COX-1 inhibitory activity with IC50 values of 5.3, 16.2, 30.2, 41.0 and 56.8 µM, respectively. Meanwhile, compounds 3-8 showed potent COX-2 inhibitory activity with IC50 values of 3.1, 5.6, 3.0, 5.1, 3.2 and 3.7 µM, respectively. In addition, compound 1 exhibited antituberculosis activity with 96.1% inhibition at concentration of 10 µM.

Design and synthesis of novel soluble 2,5-diketopiperazine derivatives as potential anticancer agents.

Non-protected 2,5-diketopiperazine derivatives have poor solubility thus with negative impact on their bioavailability. In the present study, twenty-one novel soluble mono-protected, and three non-protected 2,5-diketopiperazine derivatives were designed and synthesized. Their anticancer activity to ten cell lines were evaluated by using CCK8 assay, and the results showed that about half of the mono-protected derivatives had broad-spectrum anticancer activity. Among allyl-protected derivatives, compound 4m had strong activity to all the cell lines (IC50 = 0.5-4.5 µM), especially to the cancer cell lines U937 (IC50 = 0.5 µM) and K562 (IC50 = 0.9 µM). Compound 4m could become a lead compound for further development for anticancer agents.

Silver nanoaggregates on chitosan functionalized graphene oxide for high-performance surface-enhanced Raman scattering.

Herein we describe a self-assembly synthesis of graphene oxide/Ag nanoparticles nano-composites (GO/CS/AgNPs) by non-covalent attachment of AgNPs to chitosan (CS) functionalized graphene oxide (GO) sheets. The negatively charged AgNPs are prone to form aggregates on GO/CS via electrostatic interaction, which is extremely beneficial to the surface-enhanced Raman scattering (SERS) detection of aromatic molecules. Taking advantage of the enrichment of target molecules on GO, the obtained hybrids exhibit strong SERS activity to aromatic molecules (trypan blue and methylene blue). Furthermore, SERS signals of a negatively charged molecule (trypan blue) are stronger than signals of a positively charged molecule (methylene blue) due to the different adsorption capacity of GO/CS/AgNPs for the two opposite charged molecules through electrostatic interaction. Moreover, GO/CS/AgNPs remarkably enhance the main peaks of l-phenylalanine, in comparison with the silver nanoparticles, showing great potential for biomedical applications.