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A new naphthyridine analogue, named streptonaphthyridine A (1), together with eight previously reported compounds (2–9), were isolated from a Mariana Trench sediment-associated actinomycete Streptomyces sp. SY2111. Planar structure of streptonaphthyridine A was established by analyses of its HRESIMS data and extensive NMR spectra and its absolute configuration was determined by a combination of single crystal X-ray diffraction analysis and optical rotation calculations. Streptonaphthyridine A (1) had antiproliferative activity against human glioma U87MG and U251 cells with IC50 values of 7.9 ± 1.3 and 13.4 ± 2.7 µM, respectively, and the known compound monomethylsulochrin (7) showed more potent activity with IC50 values of 0.6 ± 0.1 µM for U87MG cells and 0.1 ± 0.0 µM for U251 cells. [ABSTRACT FROM AUTHOR]

Marine-derived Streptomyces actinomycetes are one of the most important sources for the discovery of novel bioactive natural products. This study characterized the isolation, structural elucidation and biological activity evaluation of thirty compounds, including twelve previously undescribed compounds, namely hygrocins K–U (5–13, 17 and 18) and streptophenylpropanamide A (23), from the marine-associated actinomycete Streptomyces sp. ZZ1956. Structures of the isolated compounds were determined by a combination of extensive NMR spectroscopic analyses, HRESIMS data, the Mosher's method, ECD calculations, single crystal X-ray diffraction and comparison with reported data. Hygrocins C (1), D (2), F (4), N (8), Q (11) and R (12), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), echoside C (27), echoside A (28) and 11,11′-O-dimethylelaiophylin (30) had antiproliferative activity (IC50: 0.16–19.39 μM) against both human glioma U87MG and U251 cells with hygrocin C as the strongest active compound (IC50: 0.16 and 0.35 μM, respectively). The analysis of the structure–activity relationship indicated that a small change in the structures of the naphthalenic ansamycins had significant influence on their antiglioma activities. Hygrocins N (8), O (9), R (12), T (17) and U (18), 2-amino-6-hydroxy-7-methyl-1,4-naphthoquinone (21), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), 3′-methoxy(1,1′,4′,1″-terphenyl)-2′,6′-diol (26), echoside C (27) and echoside A (28) showed antibacterial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli with MIC values of 3–48 μg/mL. [ABSTRACT FROM AUTHOR]

Marine-derived Penicillium fungi are one of the most important sources for the discovery of new bioactive natural products. This study characterized the isolation, structures, and antiglioma activities of twelve compounds, including three novel ones—penipyridinone B (1), 11S-(−)-penilloid A (2), and 11R,14E-(+)-penilloid A (3)—from the marine fungus Penicillium sp. ZZ1750. The structures of the novel compounds were determined via extensive nuclear magnetic resonance (NMR) spectroscopic analyses, high-resolution electrospray ionization mass spectroscopy (HRESIMS) data, Mosher's method, optical rotation (OR) calculations, and electronic circular dichroism (ECD) calculations. Penipyridinone B represents the first example of its structural type and showed potent antiglioma activity, with IC50 values of 2.45 μM for U87MG cells and 11.40 μM for U251 cells. The known compounds of questiomycin A (9) and xanthocillin X (10) also showed antiproliferative activity against both U87MG and U251 cells, with IC50 values of 13.65 μM to 22.56 μM. The antiglioma activity of questiomycin A and xanthocillin X may be related to the promotion of reactive oxygen species (ROS) production, the reduction of mitochondrial membrane potential (MMP), and the enhancement of caspase-3 enzyme activity. [ABSTRACT FROM AUTHOR]

Four previously undescribed compounds talaromyester A ( 1 ) and purpuresters C-E ( 2 - 4 ), together with known purpurester A ( 5 ) and purpuride G ( 6 ), were isolated from the metabolites produced by the Mariana Trench sediment-derived fungus Talaromyces sp. SY2250. Compounds 2 - 5 , two pairs of racemates, were separated on a chiral HPLC column. Structures of the isolated compounds were determined based on their HRESIMS data, extensive NMR spectroscopic analyses, and optical rotation calculations. Purpuride G ( 6 ) showed antiproliferative activity against glioma cells and may be the main active compound responsible for the activity of the crude extract prepared from the culture of Talaromyces sp. SY2250 in rice medium.

The new (±)-bacillipyrrole A (1) and bacillipyrazine A (2), together with seven known compounds, were isolated from a culture of the Mariana Trench sediment-derived bacterium Bacillus subtilis SY2101 in rice medium. Structures of the new compounds were elucidated by their HRESIMS data and NMR spectroscopic analyses. The known compound 3,5,6-trimethylpyrazine-2-methyl acetate (4) showed antiproliferative activity against human glioma U87MG cells with an IC 50 value of 22.6 ± 2.8 μM. [Display omitted] • Nine metabolites were isolated from the hadal bacterium Bacillus subtilis SY2101. • (±)-Bacillipyrrole A and bacillipyrazine A were characterized as new compounds. • 3,5,6-Trimethylpyrazine-2-methyl acetate (4) showed antiglioma activity. [ABSTRACT FROM AUTHOR]

Marine-derived Streptomyces actinomycetes are one of the most important sources for the discovery of novel bioactive natural products. This study characterized the isolation, structural elucidation and biological activity evaluation of thirty compounds, including twelve previously undescribed compounds, namely hygrocins K–U (5–13, 17 and 18) and streptophenylpropanamide A (23), from the marine-associated actinomycete Streptomyces sp. ZZ1956. Structures of the isolated compounds were determined by a combination of extensive NMR spectroscopic analyses, HRESIMS data, the Mosher’s method, ECD calculations, single crystal X-ray diffraction and comparison with reported data. Hygrocins C (1), D (2), F (4), N (8), Q (11) and R (12), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), echoside C (27), echoside A (28) and 11,11′-O-dimethylelaiophylin (30) had antiproliferative activity (IC50: 0.16–19.39 μM) against both human glioma U87MG and U251 cells with hygrocin C as the strongest active compound (IC50: 0.16 and 0.35 μM, respectively). The analysis of the structure–activity relationship indicated that a small change in the structures of the naphthalenic ansamycins had significant influence on their antiglioma activities. Hygrocins N (8), O (9), R (12), T (17) and U (18), 2-amino-6-hydroxy-7-methyl-1,4-naphthoquinone (21), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), 3′-methoxy(1,1′,4′,1″-terphenyl)-2′,6′-diol (26), echoside C (27) and echoside A (28) showed antibacterial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli with MIC values of 3–48 μg/mL.

Marine-derived Penicillium fungi are one of the most important sources for the discovery of new bioactive natural products. This study characterized the isolation, structures, and antiglioma activities of twelve compounds, including three novel ones—penipyridinone B (1), 11S-(−)-penilloid A (2), and 11R,14E-(+)-penilloid A (3)—from the marine fungus Penicillium sp. ZZ1750. The structures of the novel compounds were determined via extensive nuclear magnetic resonance (NMR) spectroscopic analyses, high-resolution electrospray ionization mass spectroscopy (HRESIMS) data, Mosher’s method, optical rotation (OR) calculations, and electronic circular dichroism (ECD) calculations. Penipyridinone B represents the first example of its structural type and showed potent antiglioma activity, with IC50 values of 2.45 μM for U87MG cells and 11.40 μM for U251 cells. The known compounds of questiomycin A (9) and xanthocillin X (10) also showed antiproliferative activity against both U87MG and U251 cells, with IC50 values of 13.65 μM to 22.56 μM. The antiglioma activity of questiomycin A and xanthocillin X may be related to the promotion of reactive oxygen species (ROS) production, the reduction of mitochondrial membrane potential (MMP), and the enhancement of caspase-3 enzyme activity.

Pseurotin A was isolated from a culture of marine Bacillus sp. FS8D and showed to be active against the proliferation of four different glioma cells with IC50 values of 0.51-29.3 μM. It has been found that pseurotin A downregulated the expression of tumour glycolytic enzymes pyruvate kinase M2 (PKM2) and lactate dehydrogenase 5 (LDH5) and upregulated the expression of pyruvate dehydrogenase beta (PDHB), adenosine triphosphate synthase beta (ATPB) and cytochrome C (Cyto-C), the important regulators for tricarboxylic acid cycle and oxidative phosphorylation. The data suggested that targeting multiple metabolic enzymes might be one of the antiglioma mechanisms of pseurotin A. [ABSTRACT FROM AUTHOR]

Novel tetrahydroisoquinoline (THI) analogs were designed, synthesized, and their antiglioma activity was evaluated. The results showed that 6,8-dimethoxy-1-(2′-methoxybiphenyl-4-ylmethyl)-1,2,3,4-tetrahydroisoquinoline hydrochloride ( 25) demonstrated improved potency, and selectivity on C6 rat glioma vs cultured rat astrocytes (EC 0.63 μM vs. 10.85 μM) compared to our recent lead molecule EDL-155 (EC 1.5 μM vs. 27.4 μM). The isomers of 25 were isolated using a semi-preparative high-performance liquid chromatography (HPLC) method, and their in vitro biological evaluation revealed that (+) 25 was the most active, and it was nearly 21 fold more potent than (−) 25, suggesting the antiglioma profile is influenced by stereochemical factors. [ABSTRACT FROM AUTHOR]

Seven novel compounds, namely peniresorcinosides A–E (1–5), penidifarnesylin A (6), and penipyridinone A (7), together with the 11 known ones 8–17, were isolated from a culture of the marine-associated fungus Penicillium sp. ZZ1750 in rice medium. The structures of the new compounds were established based on their high-resolution electrospray ionization mass spectroscopy (HRESIMS) data, extensive nuclear magnetic resonance (NMR) spectroscopic analyses, chemical degradation, Mosher's method, 13C-NMR calculations, electronic circular dichroism (ECD) calculations, and single crystal X-ray diffraction. Peniresorcinosides A (1) and B (2) are rare glycosylated alkylresorcinols and exhibited potent antiglioma activity, with IC50 values of 4.0 and 5.6 µM for U87MG cells and 14.1 and 9.8 µM for U251 cells, respectively. [ABSTRACT FROM AUTHOR]

Mouse glioma-26 (G-26) cell line established in this laboratory was used in the study. The in vitro effect of ascorbyl esters, viz., ascorbyl-palmitate (As-P), -stearate (As-S) and mouse interferon-α/β (MulFN-α/β) on the glioma cell viability, proliferation and glutathione S-transferase (GST) activity was investigated. Cell viability and proliferation were examined by colorimetric MTT assay and [H]-thymidine incorporation, respectively. Incubation (24 h) of G-26 cells with As-S, As-P or MulFN-α/β, resulted in a dose dependent decrease in cell viability (IC=125μM As-S; 175μM As-P and 3.6×10 U/ml MulFN-α/β) and proliferation (IC=157μM As-S; 185μM As-P and 3.6×10 U/ml MulFN-α/β). A combined exposure to 175 μM As-S and 800 U/ml of MulFN-α/β resulted in a greater than an additive effect on cell viability and proliferation. The inhibition of cell proliferation/viability by interferon was species specific and was observed only with homologous MulFN-α/β, but not with human interferon-α lymphoblastoid or human interferon-β. Ascorbyl esters inhibited cytosolic GST activity (1-50=15.0 μM As-S and 28.5 μM As-P) towards 1-chloro-2,4-dinitrobenzene in a dose dependent manner. The apparent Ki values for affinity purified GST, deduced from Dixon plots were 0.95 μM and 2.0 μM for As-S and As-P, respectively. Significant inhibition of GST was also observed in the cytosol isolated from G-26 cells exposed to 300 μM As-S or 800 U/ml MulFN-α/β. [ABSTRACT FROM AUTHOR]

Pseurotin A was isolated from a culture of marine Bacillus sp. FS8D and showed to be active against the proliferation of four different glioma cells with IC 50 values of 0.51-29.3 μM. It has been found that pseurotin A downregulated the expression of tumour glycolytic enzymes pyruvate kinase M2 (PKM2) and lactate dehydrogenase 5 (LDH5) and upregulated the expression of pyruvate dehydrogenase beta (PDHB), adenosine triphosphate synthase beta (ATPB) and cytochrome C (Cyto-C), the important regulators for tricarboxylic acid cycle and oxidative phosphorylation. The data suggested that targeting multiple metabolic enzymes might be one of the antiglioma mechanisms of pseurotin A.