Emprego de compostos amídicos para o controle de Penicillium expansum em maçã

Abstract

Brazilian fruit production is growing, but the production suffers losses, mainly the deterioration in the postharvest. The deterioration associated with fungal contamination can occur during transport and storage, reducing fruits quality. Colletotrichum gloeosporioides and Penicillium expansum are two main fungal diseases in papaya and apple production, respectively. The use of antifungal need to be safe for human health and environmentally friendly have great importance. Synthetic compounds molecularly identical or analogous to natural compounds could be an alternative to the replacement of fungicides. In this context, the study aimed to use synthetic antimicrobial peptides, Astacidina-2 and c(1-18)[Gln1, Thr2,6,11,15,D-Pro9] Gm, and analogues of the natural product capsaicin to inhibiting the growth of fungi C. gloeosporioides and P. expansum. Specifically, capsaicin analogues used in this study were N-benzilbutanamide, N-(3 methoxybenzyl) butanamide, N-(4-hydroxy-3-methoxybenzyl)hexanamide, N-(4-hydroxy-3-methoxybenzyl) tetradecanamide. The minimum inhibitory concentration (MIC) was determined in a liquid medium using natamycin as a growth inhibition control. Among all evaluated compounds, the peptide c(1-18)[Gln1, Thr2,6,11,15,D-Pro9]-Gm presented the lowest MIC against C. gloeosporioides and P. expansum (19.25 μM and 2.40 μM respectively). For C.gloeosporioides capsaicin and all analogues showed MIC of 800 μM. The capsaicin inhibited the growth of P. expasum at a concentration of 400 μM and loss of activity was observed with the analogous N-(3-methoxybenzyl)butanamide and N-(4-hydroxy-3-methoxybenzyl)hexanamide (both MIC = 600 μM). N-benzilbutanamide and N-(4-hydroxy-3-methoxybenzyl)tetradecanamide were two times less active than capsaicin. In vivo analysis was performed only on apple with the compounds c(1-18)[Gln1, Thr2,6,11,15,D-Pro9]-Gm, N-(3-methoxybenzyl)butanamide and N-(4- hydroxy-3 methoxybenzyl)hexanamide. The compounds do not have fungicidal effect at the concentrations tested for P. expansum.