ABSTRACT
Three new alkaloids, iizukines C-E (1-3), including two aspochalasins (1 and 2), and one brasiliamide derivative (3), along with two known aspochalasins, rosellichalasin (4) and cytochalasin Z17 (5), were isolated from the culture of Aspergillus iizukae. Compound 1 was the first aspochalasin uniquely featuring a 1,2,4-triazole functionality, and 3 showed a pair of NMR signals in CDCl3 with a ratio of about 2:1 due to the existence of conformational isomers. Their structures were determined by extensive spectroscopic analyses and single-crystal X-ray diffractions. In particular, the 1,2,4-triazole moiety in 1 was assigned on the basis of extremely valuable 1H-15N HMBC spectrum. Compound 1 exhibited cytotoxic effect towards HL-60 and A549 cell lines with IC50 values of 3.8 and 7.2⯵M, respectively.
Subject(s)
Alkaloids/isolation & purification , Alkaloids/pharmacology , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/pharmacology , Aspergillus/chemistry , Cell Proliferation , Cytochalasins/chemistry , Neoplasms/drug therapy , Soil/chemistry , Alkaloids/chemistry , Antineoplastic Agents/chemistry , Humans , Molecular Structure , Neoplasms/pathology , Tumor Cells, CulturedABSTRACT
Three new diastereomers of polyketides (PKs), raistrickiones A−C (1â»3), together with two new analogues, raistrickiones D and E (4 and 5), were isolated from a highly productive strain of Penicillium raistrickii, which was subjected to an experimental thermo-change strategy to tap its potential of producing new secondary metabolites. Metabolites 1 and 2 existed in a diastereomeric mixture in the crystal packing according to the X-ray data, and were laboriously separated by semi-preparative HPLC on a chiral column. The structures of 1â»5 were determined on the basis of the detailed analyses of the spectroscopic data (UV, IR, HRESIMS, 1D, and 2D NMR), single-crystal X-ray diffractions, and comparison of the experimental and calculated electronic circular dichroism spectra. Compounds 1â»5 represented the first case of 3,5-dihydroxy-4-methylbenzoyl derivatives of natural products. Compounds 1â»5 exhibited moderate radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH).
Subject(s)
Biphenyl Compounds/chemistry , Free Radical Scavengers/chemistry , Penicillium/metabolism , Picrates/chemistry , Polyketides/chemistry , Chromatography, High Pressure Liquid , Circular Dichroism , Crystallography, X-Ray , Free Radical Scavengers/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Polyketides/isolation & purification , Stereoisomerism , TemperatureABSTRACT
AIM: To study the chemical constituents in the mycelia of Hypomyces sp.. METHODS: Silica gel column chromatography was employed for the isolation and purification. Chemical and spectral methods were used to determine the structures of the isolated compounds. RESULTS: Two compounds were isolated and identified as: hypomycin C (I) and hypomycin D (II). CONCLUSION: Compounds I and II are new compounds.
Subject(s)
Hypocreales/chemistry , Perylene/isolation & purification , Quinones/isolation & purification , Chromatography, Gel/methods , Fermentation , Molecular Conformation , Molecular Structure , Mycelium/chemistry , Perylene/analogs & derivatives , Perylene/chemistry , Quinones/chemistryABSTRACT
OBJECTIVE: To study the chemical constituents of Shiraia bambusicola. METHOD: Column chromatography with silica gel was employed for the isolation and purification of constituents. The structures were elucidated by means of chemical and spectroscopic data. RESULT: Seven compounds were obtained and identified as hypocrellin A (I), hypocrellin B (II), hypocrellin C (III), hypomycin A (IV), ergosterol (V), ergosterol peroxide (VI) and 1,8-dihydroxy anthraquinone (VII). CONCLUSION: Compounds (IV) (VII) were separated from Shiraia bambusicola for the first time.
