Selection of electron-deficient substances as antifungal candidates

A new class of bioactive compounds synthesized from Morita-Baylis–Hillman adducts (MBH) showed antioxidant and anti-melanogenesis activities.Therefore, the present researchwork explores the relationship between antifungal activity and the responsible chemical function of MBH adducts and their derivatives (alcohols, acetates, phosphonates and hydrazono phosphonates). It was against the phyto-pathogenic fungi Aspergillus niger , Fusarium oxysporum , Penicillium occitanis , Trichoderma reesei , Stachybotrys microspora , Fusarium solani,Trichoderma parceramosum , Fusarium aethiopicum , Alternaria alternata and Aspergillus flavus using the agar diffusion method. Our results showed that acetates exhibited varying degrees of antifungal activity against several fungi tested, while single alcohol revealed a weaker activity. The five-membered ring derivative was the most potent with an inhibition zone diameter of 4.75 ± 0.21, 6.1 ± 0.14, 4.35 ± 0.21, 3.9 ± 0.14, 4.54 ± 0.11, 3.55 ± 0.07, 3 ± 0, 3.2 ± 0.2, 5.36 ± 0.26 and 5.06 ± 0.5 cm against F. oxysporum, T. parceramosum, S. microspora, T. reesei, F. solani, P. occitanis, A. niger, F. aethiopicum, A. alternata and A. flavus, respectively. Compared to the positive control, i.e., the nystatin, the most tested compounds exhibited moderate to strong growth inhibitory effects, depending on the radical group. The originality of this work is that several adducts were evaluated, for the first time. Acetates or alcohols with five and six-membered rings exhibited good antifungal activity. Linear or cyclic molecules coupled to five carbons generally carried an antifungal activity. The five-membered carbon acetates have thus been proven to be the most effective derivatives.