Expedient Discovery for Novel Antifungal Leads Inhibiting Fusarium graminearum: 3-(Phenylamino)quinazolin-4(3H)-ones Deriving from Systematic Optimizations on a Tryptanthrin Structure

The ever-increasing resistance of Fusarium graminearum has emerged as a pressing agricultural issue that could be settled by developing novel fungicides owning inimitable action mechanisms. With the aim of discovering novel antifungal leads inhibiting F. graminearum, a tryptanthrin structure was dexterously optimized to generate 30 novel quinazolin-4(3H)-one derivatives. The aforementioned optimization generated the molecule C17 that owned exhilarating in vitro anti-F. graminearum effect (EC50 value = 0.76 mu g/mL). Whereafter, the in vivo anti-F. graminearum preventative efficacy of the molecule C17 was measured to be 59.5% at 200 mu g/mL, which was approximately comparable with that of carbendazim (64.9%). Furthermore, morphological observations indicated that the molecule C17 could cause the hypha to become slender and dense, distort the outline of cell walls, induce an increase in liposome numbers, and cause the reduction of mitochondria numbers. The above results have emerged as an obbligato complement for developing novel antifungal leads that could effectively control Fusarium head blight.