Antifungal activity of β-carbolines on Penicillium digitatum and Botrytis cinerea.
Olmedo, G.M., Cerioni, L., González, M.M., Cabrerizo, F.M., Rapisarda, V.A. and Volentini, S.I.
1Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, CP T4000ILI, San Miguel de Tucumán, Tucumán, Argentina.
IIB-INTECH (sede Chascomús), UNSAM-CONICET, Intendente Marino Km 8,2, CC 164, CP 7130, Chascomús, Buenos Aires, Argentina.
Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, CP T4000ILI, San Miguel de Tucumán, Tucumán, Argentina. Electronic address: sabrina@fbqf.unt.edu.ar.
β-carbolines (βCs) are alkaloids widely distributed in nature that have demonstrated antimicrobial properties. Here, we tested in vitro six βCs against Penicillium digitatum and Botrytis cinerea, causal agents of postharvest diseases on fruit and vegetables. Full aromatic βCs (harmine, harmol, norharmane and harmane) exhibited a marked inhibitory effect on conidia germination at concentrations between 0.5 and 1 mM, while dihydro-βCs (harmalina and harmalol) only caused germination delay. Harmol showed the highest inhibitory effect on both fungal pathogens. After 24 h of exposure to 1 mM harmol, conidia revealed a severe cellular damage, exhibiting disorganized cytoplasm and thickened cell wall. Harmol antimicrobial effect was fungicidal on B. cinerea, while it was fungistatic on P. digitatum. Conidia membrane permeabilization was detected in treatments with harmol at sub-inhibitory and inhibitory concentrations, for both pathogens. In addition, residual infectivity of P. digitatum on lemons and B. cinerea on blueberries was significantly reduced after exposure to this alkaloid. It also inhibited mycelial growth, preventing sporulation at the highest concentration tested. These results indicate that harmol might be a promising candidate as a new antifungal molecule to control causal agents of fruit diseases.
Food Microbiology 62: 9-14 (2017)