ABSTRACT
Cultivation of the mangrove rhizosphere soil-derived fungus Penicillium janthinellum HK1-6 with NaBr led to the isolation of two new brominated azaphilones, penicilones G and H (5, 6), two new tricyclic polyketides, penijanthinones A and B (7, 8), and two known azaphilones, penicilones A and B (1, 2). The planar structures and relative configurations of the new compounds were elucidated using comprehensive spectroscopic methods including 1D and 2D NOE spectra. Their absolute configurations were determined by chemical conversions, TDDFT ECD calculations, and comparisons of their ECD spectra. Interestingly, the NaBr-induced brominated azaphilones (5, 6) had the opposite configuration at C-7 compared to the chloro analogues (3, 4) produced by this fungus cultivated with sea salt. Ester hydrolysis of penicilone B (2) afforded the carboxylic acid side chain 2,4-dimethyldec-2-enoic acid (9), with a 4 S configuration assigned by its specific rotation. Penicilone H (6) showed antibacterial activity with MIC values ranging from 3.13 to 12.5 µg/mL.
Subject(s)
Benzopyrans/metabolism , Penicillium/metabolism , Polyketides/metabolism , Soil Microbiology , Benzopyrans/chemistry , Benzopyrans/pharmacology , Bromides/pharmacology , Cell Line, Tumor , Halogenation , Humans , Magnetic Resonance Spectroscopy , Polyketides/chemistry , Polyketides/pharmacology , Sodium Compounds/pharmacologyABSTRACT
Two new unsaturated fatty acids, 6R,8R-dihydroxy-9Z,12Z-octadecadienoic acid (1) and methyl-6R,8R-dihydroxy-9Z,12Z-octadecadienoate (2), and two known 9Z,12Z-octadecadienoic acid analogues (3, 4) together with a known sesquiterpenoid (5) were isolated from the mangrove rhizosphere soil-derived fungus Penicillium javanicum HK1-22. An acetonide derivative (1a) from 1 was also prepared. The relative configuration of 1 was determined by analysis of the 1D and 2D NOE spectra of 1a. The absolute configuration of 1 was assigned on the basis of biogenetic considerations. The antifungal activity of the high yield compound 5 was evaluated against four strains of crop pathogens and it showed significant antifungal activities against all the tested strains.
Subject(s)
Fatty Acids, Unsaturated/isolation & purification , Penicillium/chemistry , Rhizosphere , Soil Microbiology , Wetlands , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Carbon-13 Magnetic Resonance Spectroscopy , Crops, Agricultural/microbiology , Fatty Acids, Unsaturated/chemistry , Fatty Acids, Unsaturated/pharmacology , Penicillium/classification , Penicillium/genetics , Phylogeny , Proton Magnetic Resonance Spectroscopy , Spectrometry, Mass, Electrospray IonizationABSTRACT
Three novel monomeric naphtho-γ-pyrones, peninaphones A-C (compounds 1-3), along with two known bis-naphtho-γ-pyrones (compounds 4 and 5) were isolated from mangrove rhizosphere soil-derived fungus Penicillium sp. HK1-22. The absolute configurations of compounds 1 and 2 were determined by electronic circular dichroism (ECD) spectra, and the structure of compound 3 was confirmed by single-crystal X-ray diffraction analysis. Compounds 4 and 5 are a pair of hindered rotation isomers. A hypothetical biosynthetic pathway for the isolated monomeric and dimeric naphtho-γ-pyrones is also discussed in this study. Compounds 1-3 showed antibacterial activity against Staphylococcus aureus (ATCC 43300, 33591, 29213, and 25923) with minimum inhibitory concentration (MIC) values in the range of 12.5-50 µg/mL. Compound 3 exhibited significant activity against the rice sheath blight pathogen Rhizoctonia solani.
Subject(s)
Aquatic Organisms/chemistry , Basidiomycota/drug effects , Penicillium/chemistry , Pyrones/chemistry , Pyrones/pharmacology , Staphylococcus aureus/drug effects , Anti-Infective Agents/chemistry , Anti-Infective Agents/isolation & purification , Anti-Infective Agents/pharmacology , Circular Dichroism , Microbial Sensitivity Tests , Molecular Structure , X-Ray DiffractionABSTRACT
Four new azaphilones, penicilones A-D (1-4), were isolated from the mangrove rhizosphere soil-derived fungus Penicillium janthinellum HK1-6. Their planar structures and absolute configurations were determined by extensive analysis of NMR spectroscopic data, ECD spectra, the modified Mosher's method, and chemical conversions. Interestingly, 1 and 2 had the opposite configuration at C-7 compared to the closely related chloro analogues 3 and 4. Ester hydrolysis of 2 and 4 afforded their parental azaphilones, named penicilones E (5) and F (6). Compounds 1-6 were evaluated for their antibacterial activities in vitro. Penicilones B-D (2-4) showed potent anti-MRSA (Staphylococcus aureus ATCC 43300, ATCC 33591) activities with MIC values ranging from 3.13 to 6.25 µg/mL.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Benzopyrans/isolation & purification , Benzopyrans/pharmacology , Methicillin-Resistant Staphylococcus aureus/drug effects , Penicillium/chemistry , Pigments, Biological/isolation & purification , Pigments, Biological/pharmacology , Anti-Bacterial Agents/chemistry , Benzopyrans/chemistry , Drug Screening Assays, Antitumor , Marine Biology , Microbial Sensitivity Tests , Molecular Structure , Pigments, Biological/chemistry , Staphylococcus aureus/drug effectsABSTRACT
A new prenylated indole alkaloid, named paraherquamide J (1), together with four known compounds (2-5), were isolated from the mangrove rhizosphere soil-derived fungus Penicillium janthinellum HK1-6. The planar structure and relative configuration of 1 were determined by detailed analysis of the spectroscopic data especially the NOESY spectrum. The absolute configuration of 1 was determined by ECD spectra. Compound 2 was first isolated as a natural product and named as paraherquamide K. All isolated metabolites were evaluated for their antibacterial, topoisomerase I (topo I) inhibitory activities and lethality towards brine shrimp Artemia salina.