Foliar epicuticular wax of Arrabidaea brachypoda:: flavonoids and antifungal activity

The epicuticular wax of the leaves of Arrabidaea brachypoda was analyzed for its flavonoid content and four compounds (1-4) were isolated. They are known flavonoids and showed antifungal activity against Cladosporium sphaerospermum. They were identified by mass spectrometry, proton nuclear magnetic resonance spectroscopy and nuclear Overhauser effect spectroscopy (NOESY) as 3',4'-dihydroxy-5,6,7-trimethoxyflavone (1), cirsiliol (2), cirsimaritin (3) and hispidulin (4). Two major chemical features resulting from this work are the first report of 1 as a natural product and the first finding of cirsiliol in Bignoniaceae. (C) 2002 Elsevier Science Ltd. All rights reserved.