prohexadione-ca and naringenin

Novel flavonoids were formed in young leaves of apple (Malusxdomestica) after treatment with the dioxygenase inhibitor prohexadione-Ca, which is known to reduce the incidence and severity of fire blight caused by Erwinia amylovora and other plant diseases. The compounds were isolated and identified as luteoliflavan, luteoliflavan 5-glucoside, eriodictyol 7-glucoside and 6"-O-trans-p-coumaroyleriodictyol 3'-glucoside. These flavonoids represent a novel biosynthetic pathway in apple leading to the formation of 3-deoxyflavans. Concomitantly, the content of regularly occurring phenylpropanoids is also influenced by prohexadione-Ca with increasing amounts of hydroxycinnamic acids and decreasing flavan-3-ols and flavonols. The altered flavonoid metabolism may be related to the lowered pathogen incidence though the isolated novel flavonoids do not exhibit antibacterial activity.

Topics: Chlorogenic Acid; Coumaric Acids; Enzyme Inhibitors; Flavanones; Flavonoids; Ketoglutaric Acids; Malus; Nuclear Magnetic Resonance, Biomolecular; Oxygenases; Plant Leaves; Spectrophotometry, Ultraviolet; Time Factors