Photodynamic inactivation (PDI) or antibacterial photodynamic therapy (aPDT) is a method based on the use of a photosensitizer, light of a proper wavelength and oxygen, which combined together leads to an oxidative stress and killing of target cells. PDI can be applied towards various pathogenic bacteria independently on their antibiotic resistance profile. Optimization of photodynamic treatment to eradicate the widest range of human pathogens remains challenging despite the availability of numerous photosensitizing compounds. Therefore, a search for molecules that could act as adjuvants potentiating antibacterial photoinactivation is of high scientific and clinical importance. Here we propose farnesol (FRN), a well described sesquiterpene, as a potent adjuvant of PDI, which specifically sensitizes Staphylococcus aureus to 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetratosylate (TMPyP) upon red light irradiation. Interestingly, the observed potentiation strongly depends on the presence of light. Analysis of this combined action of FRN and TMPyP, however, showed no influence of farnesol on TMPyP photochemical properties, i.e. the amount of reactive oxygen species that were produced by TMPyP in the presence of FRN. The accumulation rate of TMPyP in Staphylococcus aureus cells did not change, as well as the influence of staphyloxanthin inhibition. The precise mechanism of observed sensitization is unclear and probably involves specific molecular targets.

光动力灭活（PDI）或抗菌光动力疗法（aPDT）是一种基于使用光敏剂、适当波长的光和氧气的方法，它们结合在一起导致氧化应激并杀死靶细胞。 PDI 可应用于各种病原菌，独立于其抗生素耐药性。尽管有多种光敏化合物可用，但优化光动力治疗以根除最广泛的人类病原体仍然具有挑战性。因此，寻找可作为增强抗菌光灭活佐剂的分子具有很高的科学和临床重要性。在这里，我们提出金合欢醇（FRN），一种充分描述的倍半萜烯，作为 PDI 的有效佐剂，它特异性地使金黄色葡萄球菌对 5,10,15,20-四（1-甲基吡啶鎓-4-基）卟啉四甲苯磺酸酯（TMPyP）敏感。红光照射。有趣的是，观察到的增强作用很大程度上取决于光的存在。然而，对 FRN 和 TMPyP 的这种联合作用的分析表明，金合欢醇对 TMPyP 光化学性质（即在 FRN 存在的情况下由 TMPyP 产生的活性氧物质的量）没有影响。金黄色葡萄球菌细胞中TMPyP的积累率没有变化，葡萄球菌黄素抑制的影响也没有变化。观察到的致敏作用的确切机制尚不清楚，可能涉及特定的分子靶标。