Antibacterial and antioxidant activity-guided isolation studies on Fusarium sp. associated with the ascidian Botryllus schlosseri

This study aimed to isolate the active compounds from the extract of Fusarium sp. for antibacterial and antioxidant activities. The extract and isolated compounds from The Fungus of Fusarium were tested against two Gram-positive bacteria, viz. Bacillus subtilis (ATCC 6633) and Staphylococcus aureus (ATCC 25923), and two Gram-negative bacteria, viz. Escherichia coli (ATCC 25922) and Vibrio cholerae (ATCC 14035) using the agar disc diffusion assay and minimum inhibitory concentration (MIC). Furthermore, we analyzed also the antioxidant capacity of the extract using 2,2-Diphenyl-1-picrylhydrazyl (DPPH). The ethyl acetate extract displayed the activity against all tested bacteria and revealed antioxidant capacity. The ethyl acetate extract was purified using column chromatography and high-performance liquid chromatography (HPLC), which led to the isolation of two pyrrole compounds, named pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl), known as Cyclo(L-Leucyl-L-Prolyl) (1) and hexahydropyrrolo[1,2-a]pyrazine-1,4-dione (2) abbreviated as Cyclo(Gly-L-Pro). The antibacterial activity of compounds 1 and 2 showed significant activity against most of the tested pathogens. Compound 2 displayed the highest antioxidant capacity. Their structures were determined by electron ionization mass spectrometry (EI-MS) and nuclear magnetic resonance (NMR). This study is the first report on the isolation of Cyclo(L-Leucyl-L-Prolyl) (1) and Cyclo(Gly-L-Pro) (2) from the Fusarium sp. The results of the present study supported the active compounds from the extract of the Fusarium showed antibacterial and antioxidant activities.