Prenylated flavonoids isolated from the twigs of Artocarpus champeden as potential activators for tobacco powdery mildew and their mode of actions

Abstract Background Golovinomyces cichoracearum (DC.) is the main pathogen for tobacco powdery mildew fungus disease. Its outbreaks often result in severe harvest losses yield and quality of tobacco. Artocarpus champeden rich prenylated flavonoids, which are important plant’s defensive strategies. With aim continuously exploring bioactive natural metabolites agricultural chemicals, chemical investigations on twigs A. were carried out. Results Six new ( 1 – 6 ) five known 7 11 flavonoids isolated. Compound first example flavone whose side-chain converted into an unusual H -pyrrol-2-yl functional group. Compounds 2 3 rare flavones bearing a 4-methylfuran-2-yl moiety. The frameworks above three reported products time. Interestingly, compound showed high anti- G . activity with inhibition rate 88.3% ± 6.2. This higher than that positive control (with 81.5% 6.3) compared to negative control, compounds also potential activities rates range 50.9%–72.0%. In addition, mechanistic studies revealed it has potent direct effect conidiospores G. induces systemic acquired resistance plants, may be reasons its significant effects against Conclusions Powdery fungal disease harmful Flavonoids have been identified as sources promising antifungal agents. For combination flavonoid skeleton can give resultant more biological activities. successful isolation structure identification provide materials screening inhibitors, contribute improved utilization Graphical