Sphaeropsidones, phytotoxic dimedone methyl ethers produced by Diplodia cupressi: a structure-activity relationship...

Area of Science:

• Plant pathology
• Mycology
• Organic chemistry

Background:

• Diplodia cupressi causes cypress canker disease in the Mediterranean.
• Sphaeropsidone and episphaeropsidone are phytotoxic compounds produced by this fungus.

Purpose of the Study:

• To investigate the phytotoxic and antifungal activities of sphaeropsidone derivatives and analogues.
• To establish structure-activity relationships for these compounds.

Main Methods:

• Eight chemically modified derivatives and two natural analogues were synthesized.
• Compounds were tested for phytotoxicity on nonhost plants.
• Antifungal activity was assessed against five Phytophthora species.

Main Results:

• Specific structural features, including a C-5 hydroxy group, C-5 configuration, epoxy group, and C-2 carbonyl, are crucial for biological activity.
• A 1,4-dione derivative of sphaeropsidone exhibited enhanced antifungal activity compared to the parent compound.

Conclusions:

• Structure-activity relationships were elucidated for sphaeropsidone derivatives.
• The enhanced antifungal activity of the 1,4-dione derivative offers potential for developing novel natural fungicides for agricultural applications.