Phytotoxic dioxolanone-type secondary metabolites from Guignardia bidwellii

► Fermentation optimisation to increase phenguignardic acid amounts was carried out. ► Identification of secondary metabolites, structurally related to guignardic acid. ► All metabolites presented have not been described to date. ► They are presumably biosynthesised via deamination products of amino acids. ► Four of seven compounds showed phytotoxic activity.