Natural Product Sciences  2016;22(3):216-219

doi:10.20307/nps.2016.22.3.216

New Production of Antibacterial Polycyclic Quinazoline Alkaloid, Thielaviazoline, from Anthranilic Acid by the Marine-Mudflat-Derived Fungus Thielavia sp..

Alain Simplice LEUTOU 1 ; Keumja YUN ; Byeng Wha SON

Affiliations

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Keywords

Thielaviazoline; Polycyclic quinazoline alkaloid; Thielavia sp.; Microbial transformation

Country

Republic of Korea

Language

English

Abstract

The microbial transformation of anthranilic acid (1) by the marine-mudflat-derived fungus Thielavia sp. produced an antibacterial polycyclic quinazoline alkaloid, thielaviazoline (2). The stereostructure of the metabolite was assigned based on detailed spectroscopic data analyses including comparison of the NMR (¹H and ¹³C) data with those of reported compound (2). Compound 2 displayed in vitro antimicrobial activity against methicillin-resistant and multidrug-resistant Staphylococcus aureus (MRSA and MDRSA), with minimum inhibitory concentrations (MICs) of 6.25 and 12.5 µg/mL, respectively. Compound 2 also showed potent radical-scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) with an IC₅₀ of 11 µM, which was more active than the positive control, L-ascorbic acid (IC₅₀, 20.0 µM).