Antibacterial and herbicidal properties of secondary metabolites from fungi

Twenty-eight compounds were isolated from endophytic, soil and marine fungi and their structures were elucidated through spectroscopic methods. The isolated compounds were tested for their antibacterial and herbicidal activities against phytopathogenic bacteria and barnyard grass weed for the first time. Methyleurotinone (14) was the most potent compound against Pectobacterium carotovorum subsp. carotovorum, Pseudomonas syringae pv. syringae, Rhizobium radiobacter and Ralstonia solanacearum with minimum inhibitory concentration (MIC) values of 31.3, 125, 31.3 and 125 mg/L, respectively. Compounds 13-15 were highly effective in reducing the development of potato tuber soft rot disease caused by P. carotovorum subsp. carotovorum. Furthermore, twelve of the tested compounds induced a significant reduction in seed germination of Echinochloa crus-galli at 2 mM with compounds 8 and 26 causing complete inhibition of seed germination. Also, compounds 4, 22, 5, 8, 18 and 25-27 induced remarkable reduction of root and shoot growth of E. crus-galli at 2 mM.

Keywords: Fungi; antibacterial effects; bioactive compounds; herbicidal activity.