Lasiolactols A and B Produced by the Grapevine Fungal Pathogen Lasiodiplodia mediterranea

A strain of Lasiodiplodia mediterranea, a fungus associated with grapevine decline in Sicily, produced several metabolites in liquid medium. Two new dimeric c-lactols, lasiolactols A and B (1and 2), were characterized as (2S*,3S*,4R*,5R*,20S*,30S*,40R*,50R*)- and (2R*,3S*,4R,5R*,20R*,30S*,40R*,50R*)-5-(4-hydroxymethyl-3,5-dimethyl-tetrahydro-furan-2-yloxy)-2,4-dimethyl-tetrahydro-furan-3-yl]-methanols by IR, 1D- and 2D-NMR, and HR-ESI-MS. Other fourmetabolites were identified as botryosphaeriodiplodin, (5R )-5-hydroxylasiodiplodin, (–)-(1R,2R)-jasmonic acid, and (–)-(3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone (3-6, resp.). The absolute configuration (R) at hydroxylatedsecondary C-atom C(7) was also established for compound 3. The compounds 1–3,5,and 6, tested for their phytotoxic activities to grapevine cv. Inzolia leaves at different concentrations (0.125, 0.25, 0.5, and 1 mg/ml) were phytotoxic and compound 5 showed the highest toxicity. All metabolites did not show in vitro antifungal activity against four plant pathogens.