inactivation-pathogens-via-visible-light-photolysis-riboflavin-5

Inactivation of Pathogens <em>via</em> Visible-Light Photolysis of Riboflavin-5&#8242;-Phosphate

Riboflavin-5&#39;-phosphate (or flavin mononucleotide; FMN) is sensitive to visible light. Various compounds, including reactive oxygen species (ROS), can ...

Hsing Wu University

Tetracycline (TC) is a broad-spectrum antibiotic compound. Wastewater with TC may have an adverse effect on ecosystems. Riboflavin-5'-phosphate (FMN or flavin mononucleotide) is a non-toxic product of the phosphorylation of vitamin B and is required for the proper functioning of the humans. FMN is sensitized to ultraviolet (UV) and blue light radiation, as evidenced by the generation of reactive oxygen species (ROS). This study inspects feasible applications of blue light on FMN so as to develop a valid way of degrading TC by FMN photolysis. We used the increased rate of bacterial survival as a practical indicator of antibiotic degradation. TC in the presence of FMN solution decomposed completely after 20 W/m of blue light irradiation (TCF treatment), and the degradation of TC (D-TCF) occurred after the photolytic process. After TCF treatment, colony-forming units (CFUs) of  ( were determined for the D-TCF solution. The CFU of  preservation was 93.2% of the D-TCF solution (50 μg/mL of TC in the presence of 114 μg/mL of FMN solution treated with 20 W/m of blue light irradiation at 25 °C for 1 h) cultivation. The mass spectrum of D-TCF showed diagnostic ion signals at m/z 431.0 and 414.0 Da. The molecular formula of D-TCF was CHNO, and the exact mass was 430.44 g/mol. TC degradation by FMN photolysis can significantly decrease the antimicrobial ability of TC. The results expressed here regarding the influence of FMN photolysis on TC degradation offer an environmentally sound wastewater treatment method.

The Influence of the Degradation of Tetracycline by Free Radicals from Riboflavin-5'-Phosphate Photolysis on Microbial Viability.

Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical (O2•-) was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl, while AlCl did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl inhibited the photolytic formation of O2•-, and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride (F-) and 1 mM oxalate (C2O42-) ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the O2•- and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI.

Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography-Mass Spectrometry.

Doxycycline hyclate (DCH) and minocycline hydrochloride (MH) are tetracycline antibiotics and broad-spectrum antimicrobial agents. The changes in DCH and MH under blue light (λ = 462 nm) irradiation in alkaline conditions (BLIA) were investigated. Deactivation caused by superoxide anion radical (O) and deactivation from DCH and MH during photolysis on Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA), were studied. DCH is relatively unstable compared to MH under BLIA. The level of O generated from the MH-treated photoreaction is lower than that from DCH photolysis, and the DCH-treated photoreaction is more efficient at inactivating S. aureus and MRSA at the same radiant intensity. DCH subjected to BLIA decreased the viability of S. aureus and MRSA by 3.84 and 5.15 log, respectively. Two photolytic products of DCH (PPDs) were generated under BLIA. The mass spectra of the PPDs featured molecular ions at m/z 460.8 and 458.8. The molecular formulas of the PPDs were CHNO and CHNO, and their exact masses were 462.44 and 460.44 g/mol, respectively. These results bolster the photolytic oxidation that leads to DCH-enhanced deactivation of S. aureus and MRSA. Photochemical treatment of DCH could be applied as a supplement in hygienic processes.

Effects of free radicals from doxycycline hyclate and minocycline hydrochloride under blue light irradiation on the deactivation of Staphylococcus aureus, including a methicillin-resistant strain.

Shwu-Yuan Lee

Department of Tourism and Leisure

Hsing Wu University

Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate