New antioxidant hydroquinone derivatives from the algicolous marine fungus Acremonium sp.
A marine fungal isolate, identified as Acremonium sp., was mass cultivated and found to produce two novel hydroquinone derivatives, 7-isopropenylbicyclo[4.2.0]octa-1,3,5-triene-2,5-diol (1) and 7-isopropenylbicyclo[4.2.0]octa-1,3,5-triene-2,5-diol-5-beta-D-glucopyranoside (2). Compound 1 and its glucoside 2 possess a most unusual ring system. The new natural products (3R,4S)-3,4-dihydroxy-7-methyl-3,4-dihydro-1(2H)naphthalenone (3) and (3S,4S)-3,4-dihydroxy-7-methyl-3,4-dihydro-1(2H)-naphthalenone (4) were obtained as a 1:0.8 mixture. 2-(1-Methylethylidene)pentanedioic acid (5) was isolated for the first time as a natural product and its structure proven by X-ray analysis. In addition to these compounds an inseparable mixture of three new isomeric compounds, pentanedioic acid 2-(1-methylethylidene)-5-methyl ester (6), pentanedioic acid 2-(1-methylethylidene)-1-methyl ester (7), and pentanedioic acid 2-(1-methylethenyl)-5-methyl ester (8), was also obtained. Isolated together with the new compounds were three known hydroquinone derivatives, 9, 10, and 11. The structures of all compounds were determined by interpretation of their spectroscopic data (1D and 2D NMR, MS, UV, and IR). Each isolate was tested for its antioxidant properties, and compounds 1 and 9-11 were found to have significant activity.
Abdel-Lateff
Ahmed
A
Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115 Bonn, Germany.
König
Gabriele M
GM
Fisch
Katja M
KM
Höller
Ulrich
U
Jones
Peter G
PG
Wright
Anthony D
AD
D000164:Acremonium / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001713:Biphenyl Compounds; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D006868:Hydrolysis; D006873:Hydroquinones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism; D008968:Molecular Conformation; D015394:Molecular Structure; D010851:Picrates / Q000494:pharmacology; D013030:Spain; D013237:Stereoisomerism
D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006873:Hydroquinones; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D054303:HIV Reverse Transcriptase