Location: Natural Products Utilization ResearchTitle: Antiprotozoal and antimicrobial compounds from the plant pathogen Septoria pistaciarum Author
Submitted to: Journal of Natural Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2012
Publication Date: 4/24/2012
Citation: Kumarihamy, M., Khan, S.I., Jacob, M., Tekwani, B.L., Duke, S.O., Ferreira, D., Nanayakkara, D.N. 2012. Antiprotozoal and antimicrobial compounds from the plant pathogen Septoria pistaciarum. Journal of Natural Products. 75(5):883-889. Interpretive Summary: Chemicals from plant pathogens have potential for use as pharmaceuticals and herbicides. Three new compounds from the fungus that causes leaf spot disease of pistacio trees were found to have activity against the microbes that cause leishmania and malaria, as well three other pathogenic microbes. These compounds were also toxic to dicot and monocot plants, but their structural complexity precludes them for consideration as herbicides.
Technical Abstract: Four new 1,4-dihydroxy-5-phenyl-2-pyridinone alkaloids, 17-hydroxy-N-(O-methyl)septoriamycin A (1), 17-acetoxy-N-(O-methyl)septoriamycin A (2), 13-(S)-hydroxy-N-(O-methyl)septoriamycin A (3) and 13-(R)-hydroxy-N-(O-methyl)septoriamycin A (4), together with the known compounds (+)-cercosporin (5), (+)-14-O-acetylcercosporin (6), and (+)-di-O-acetylcercosporin (7), lumichrome, and brassicasterol were isolated from an ethyl acetate extract of a culture medium of Septoria pistaciarum. Methylation of septoriamycin A (8) with diazomethane yielded three di-O-methyl analogues, two of which existed as mixtures of rotamers. We previously reported antimalarial activity of septoriamycin A. This compound also exhibited significant activity against Leishmania donovani promastigotes. Compounds 5-7 showed in vitro activity against L. donovani promastigotes, chloroquine-sensitive (D6) and -resistant (W2) strains of Plasmodium falciparum, methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus, Mycobacterium intracellulare, Candida glabrata, and moderate cytotoxicity against a panel of cell lines. Compounds 5, 6, and 7 also exhibited moderate phytotoxic activity against both a dicot (lettuce, Lactuca sativa) and a monocot (bentgrass, Agrostis stolonifera).