UVA Photoactivation of Harmol Enhances Its Antifungal Activity against the PhytopathogensPenicillium digitatumandBotrytis cinerea.
Phytopathogenic fungi responsible for post-harvest diseases on fruit and vegetables cause important economic losses. We have previously reported that harmol (1-methyl-9H-pyrido[3,4-b]indol-7-ol) is active against the causal agents of green and gray moldsPenicillium digitatumandBotrytis cinerea, respectively. Here, antifungal activity of harmol was characterized in terms of pH dependency and conidial targets; also photodynamic effects of UVA irradiation on the antimicrobial action were evaluated. Harmol was able to inhibit the growth of both post-harvest fungal disease agents only in acidic conditions (pH 5), when it was found in its protonated form. Conidia treated with harmol exhibited membrane integrity loss, cell wall disruption, and cytoplasm disorganization. All these deleterious effects were more evident forB. cinereain comparison toP. digitatum. When conidial suspensions were irradiated with UVA in the presence of harmol, antimicrobial activity against both pathogens was enhanced, compared to non-irradiated conditions.B. cinereaexhibited a high intracellular production of reactive oxygen species (ROS) when was incubated with harmol in irradiated and non-irradiated treatments.P. digitatumshowed a significant increase in ROS accumulation only when treated with photoexcited harmol. The present work contributes to unravel the antifungal activity of harmol and its photoexcited counterpart against phytopathogenic conidia, focusing on ROS accumulation which could account for damage on different cellular targets.
INSIBIO (CONICET, UNT), Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT Tucumán, Argentina.
Gabriela M
GM
Olmedo
INSIBIO (CONICET, UNT), Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT Tucumán, Argentina.
Luciana
L
Cerioni
IIB-INTECH - UNSAM-CONICET Buenos Aires, Argentina.
María M
MM
González
IIB-INTECH - UNSAM-CONICET Buenos Aires, Argentina.
Franco M
FM
Cabrerizo
INSIBIO (CONICET, UNT), Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT Tucumán, Argentina.
Sabrina I
SI
Volentini
INSIBIO (CONICET, UNT), Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT Tucumán, Argentina.
Viviana A
VA
Rapisarda
alkaloids; cellular damage; photosensitization; reactive oxygen species; β-carboline