Saponaroxins A-C, a new 19-oxa-tricyclohenicosatetraenone and, a new dioxacyclopropacycloundecene-10-carboaldehyde and its 6,7-dihydro derivative, produced by Alternaria saponariae, a pathogen of a medicinal plant Saponaria officinalis

A new 19-oxa-tricyclohenicosatetraenone and a new dioxacyclopropacycloundecene-10-carboaldehyde and its 6,7-dihydro derivative, named saponaroxins A-C, were isolated from the culture filtrate of Alternaria saponariae a fungal pathogen of the well-known medicinal plant Saponaria officinalis. Saponaroxins A-C were characterized by spectroscopic methods. When assayed on punctured leaf segments of two weeds, Sonchus arvensis and Elytrigia repens saponaroxins B-C were found to be phytotoxic. They demonstrated moderate antimicrobial activity and low toxicity against Paramecium caudatum. Saponaroxin A was acutely toxic to P. caudatum while showed no phytotoxic nor antimicrobial activity.