The phytoalexins from cauliflower, caulilexins A, B and C: isolation, structure determination, syntheses and antifungal activity.

Our continuous search for phytoalexins from crucifers led us to examine phytoalexin production in florets of cauliflower (Brassica oleracea var. botrytis) under abiotic (UV light) elicitation. Four known (isalexin, S-(-)-spirobrassinin, 1-methoxybrassitin, brassicanal C) and three new (caulilexins A-C) phytoalexins were isolated. The syntheses and antifungal activity of caulilexins A-C against the economically important pathogenic fungi Leptosphaeria maculans, Rhizoctonia solani and Sclerotinia sclerotiorum, and the first synthesis of brassicanal C are reported.