NIGROSPORIN-A AND NIGROSPORIN-B, NEW PHYTOTOXIC AND ANTIBACTERIAL METABOLITES PRODUCED BY A FUNGUS NIGROSPORA-ORYZAE

Nigrosporin A and B, two new phytotoxic and antibacterial metabolites were isolated from a culture filtrate of Nigrospora oryzae. The active principles were absorbed on XAD-2 resin and purified by suceessive OD S-HPLC. The structures were identified by spectroscopic and derivatiza tion analysis as naphthoquinone derivatives. The substances showed phy totoxic activities, such as root elongation inhibition, necrotic effec ts, oxygen evolution inhibition, starch synthesis inhibition, and CO2 fixation inhibition at concentrations of 10-100ppm. They also showed g rowth inhibition activity against Bacillus subtilis in a disc diffusio n assay as well as when compared with streptomycin.