Studies on the therapeutic effects of pectolytic enzyme inhibitors

A few polyphenols (tannic acid and digallic acid), anthraquinone derivatives (rufianic acid and quinalizarin), and detergents (an alkylaryl sulfonate) proved to be especially effective inhibitors of pectolytic and cellulolytic enzymes of four phytopathogenic fungi. Some of these substances prevented the infection of tomato leaves withAlternaria solani. It appears, however, that inhibition of the germination of conidia was the crucial effect rather than inhibition of the enzymes. Alkylaryl sulfonate and rufianic acid were able to reduce the maceration of bean hypocotyls byRhizoctonia solani. Rufianic acid also counteracted tomato wilt, caused byFusarium oxysporum f.lycopersici, especially in the case of postinfectional application. On the other hand preinfectional rather than postinfectional application of rufianic acid had effect onVerticillium wilt of tomato.