Marioni Juliana, Romero Bianca C, Mugas Ma Laura, Martinez Florencia, Gómez Tomas I, Morales Jesús M N, Konigheim Brenda S, Borsarelli Claudio D, Nuñez-Montoya Susana C
Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba X5000HUA, Argentina.
Instituto de Bionanotecnología del NOA (INBIONATEC), Universidad Nacional de Santiago del Estero-CONICET, RN9, Km 1125, Santiago del Estero G4206XCP, Argentina.
Pharmaceutics. 2025 Apr 23;17(5):548. doi: 10.3390/pharmaceutics17050548.
: Parietin (PTN), a blue-light absorbing pigment from spp. lichens, exhibit photosensitizing properties via Type I (superoxide anion, O) and Type II (singlet oxygen, O) mechanisms, inactivating bacteria in vitro after photoexcitation. We evaluate the in vitro antifungal activity of PTN against biofilms under actinic irradiation, its role in O and O production, and the cellular stress response. : Minimum inhibitory concentration (MIC) of PTN was determined in NCPF 3111 under dark and actinic light conditions. Biofilm susceptibility was assessed at MIC/2, MIC, MICx2, MICx4, and MICx6 in the same conditions, and viability was measured by colony-forming units. Photodynamic mechanisms were examined using Tiron (O scavenger) or sodium azide (O quencher). O production was measured by the nitro-blue tetrazolium (NBT) reduction and nitric oxide (NO) generation by Griess assay. Total antioxidant capacity was studied by FRAP (Ferrous Reduction Antioxidant Potency) assay and superoxide dismutase (SOD) activity by NBT assay. : Photoexcitation of PTN reduced biofilm viability by four logs at MICx2. Sodium azide partially reversed the effect, whereas Tiron fully inhibited it, indicating the critical role of O. PTN also increased O and NO levels, enhancing SOD activity and FRAP. However, this antioxidant response was insufficient to prevent biofilm photoinactivation. : Photoinactivation of biofilms by PTN is primarily mediated by O, with a minor contribution from O and an imbalance in NO levels. These findings suggest PTN is a promising photosensitizer for antifungal photodynamic therapy.
地衣红素（PTN）是一种从地衣中提取的吸收蓝光的色素，通过I型（超氧阴离子，O）和II型（单线态氧，O）机制表现出光敏特性，在光激发后可在体外使细菌失活。我们评估了PTN在光化辐射下对生物膜的体外抗真菌活性、其在O和O产生中的作用以及细胞应激反应。：在黑暗和光化光条件下，测定了PTN对近平滑念珠菌3111的最低抑菌浓度（MIC）。在相同条件下，以MIC/2、MIC、MIC×2、MIC×4和MIC×6评估生物膜敏感性，并通过菌落形成单位测量活力。使用铁试剂（O清除剂）或叠氮化钠（O猝灭剂）研究光动力机制。通过硝基蓝四氮唑（NBT）还原法测量O的产生，通过Griess法测量一氧化氮（NO）的生成。通过铁还原抗氧化能力（FRAP）测定法研究总抗氧化能力，通过NBT测定法研究超氧化物歧化酶（SOD）活性。：在MIC×2时，PTN的光激发使近平滑念珠菌生物膜活力降低了四个对数。叠氮化钠部分逆转了这种效应，而铁试剂完全抑制了这种效应，表明O起关键作用。PTN还增加了O和NO水平，增强了SOD活性和FRAP。然而，这种抗氧化反应不足以防止生物膜光失活。：PTN对近平滑念珠菌生物膜的光失活主要由O介导，O的贡献较小，且NO水平失衡。这些发现表明PTN是一种有前途的抗真菌光动力治疗光敏剂。
