title: Flavone Biotransformation by Aspergillus niger and the Characterization of Two Newly Formed Metabolites.
abstract: Aspergillus niger isolated from Allium sativum was used at large scale fermentation (150 mg flavone/200 ml medium) to obtain suitable amounts of the products, efficient for identification. Then spectral analysis (UV, IR, (1)H-NMR, (13)C-NMR) and mass spectrometry were performed for the two products, which contributed to the identification process. The metabolite (1) was identified as 2'-hydroxydihydrochalcone, and the metabolite (2) was identified as 2'-hydroxyphenylmethylketone, which were more active than flavone itself. Antioxidant activities of the two isolated metabolites were tested compared with ascorbic acid. Antioxidant activity of metabolite (1) was recorded 64.58% which represented 79% of the antioxidant activity of ascorbic acid, and metabolite (2) was recorded 54.16% (67% of ascorbic acid activity). However, the antioxidant activity of flavone was recorded 37.50% which represented 46% of ascorbic acid activity. The transformed products of flavone have antimicrobial activity against Pseudomonas aeruginosa, Aspergillus flavus and Candida albicans, with MIC was recorded 250 µg/ml for metabolite (2) against all three organism and 500, 300, and 300 µg/ml for metabolite (1) against tested microorganisms (P. aeruginosa, Escherichia coli, Bacillus subtilis, and Klebsiella pneumonia, Fusarium moniliforme, A. flavus, Saccharomyces cerviceae, Kluveromyces lactis and C. albicans) at this order.
authors.affiliation: Tanta University, Faculty of Science, Botany Department, Mycology Research Lab., Tanta 31527, Egypt.
authors.forename: Yehia A G
authors.initials: YA
authors.lastname: Mahmoud
authors.forename: Suzan W
authors.initials: SW
authors.lastname: Assawah
authors.forename: Saleh H
authors.initials: SH
authors.lastname: El-Sharkawy
authors.forename: Amal
authors.initials: A
authors.lastname: Abdel-Salam
keywords: Anit-microbial; Antioxidant; Aspergillus; Biotransformation; Flavone