ISOLATION OF ANTIFUNGAL COMPOUNDS FROM SOME ZYGOPHYLLUM SPECIES AND THEIR BIOASSAY AGAINST 2 SOIL-BORNE PLANT-PATHOGENS

Roots and aerial shoots of Zygophyllum coccineum L., Z. album L. and Z . dumosum Boiss were extracted with solvents of increasing polarity an d tested against spore germination of Verticellium albo-atrum and Fusa rium oxysporum tsp. lycopersici. The effectiveness of each extract dep ends on the solvent, plant species, organ and test fungus. Petroleum e ther extracts were ineffective as fungistatics while the methanol extr acts possessed a high inhibitory effect toward spore germination of bo th fungi. The aqueous methanolic root extracts were inhibitory to the test fungi while that of aerial shoot showed specific suppression, dep ending on the fungus and plant species. Water or ethyl acetate root ex tracts of Z. album caused a marked suppression of spore germination of the test fungi. Six saponins were isolated from the effective extract s on silica gel and Sephadex columns. They were identified by acid hyd rolysis, alkaline saponification, IR and FAB MS. Quinovic acid was the dominant aglycone. Kaempferol was isolated from the flavonoid fractio n of Z. dumosum for the first time. Some of the isolated saponins and kaempferol provided successful control against the test plant pathogen s under greenhouse experiment when used as seed treatment.