BIOLOGICAL-ACTIVITIES OF SYNTHETIC ANALOGS OF ALTERNARIA-ALTERNATA TOXIN (AAL-TOXIN) AND FUMONISIN IN PLANT AND MAMMALIAN-CELL CULTURES

In a search for an analogue of AAL-toxin with high phytotoxicity and low mammalian toxicity, aminopentols [(AP(1)), hexacetyl AP(1) and N-acetyl AP(1)], and nine analogues (1-9), were tested for toxicity to duckweed (Lemna pausicostata), susceptible tomato (asc/asc) leaf discs, black nightshade leaf discs and mammalian cell lines, including dog kidney (MDCK), rat liver hepatoma (H4TG) and mouse fibroblasts (NIH3T3). These were compared with AAL-toxin and fumonisin B-1 (FB1). Analogue 9 at 10 mu M increased cellular leakage and chlorophyll loss from both tomato and black nightshade leaf discs. The diester 9 was the most active in the duckweed bioassay, but it was much less toxic to MDCK and H4TG cells with an IC50 of 200 mu M compared to 10 mu M for FB1. Analogue 9 and FB1 showed similar low toxicities (ICS50 = 150 mu M) to NIH3T3 cells. Among the substances tested, only analogue 9 had significant phytotoxicity and low mammalian toxicity, indicating some potential for development of safe and effective natural herbicides.