Investigating the photosensitization activities of flavins irradiated by blue LEDs

Abstract

A method for conducting structure-photosensitizing activity relationships for natural flavins and their analogues is described. Several key parameters were investigated: pH, atmosphere, irradiation time & source power.

Riboflavin and Its Derivates as Potential Photosensitizers in the Photodynamic Treatment of Skin Cancers

“…The application of blue light, which is required for the activation of flavin derivatives, might be a significant advantage when using them in the photodynamic treatment of superficially located lesions or for other photodynamic purposes that do not require deep light penetration. Due to extensive achievements in synthesizing new flavin analogues and better understanding of their photosensitizing activity, there are now real opportunities to facilitate the identification of the derivatives with the best potential in PDT [ 36 ]. Thus, it seems to be worth searching for flavin analogues that will allow us to avoid riboflavin’s disadvantages while retaining its favorable qualities, mainly its high quantum yield of singlet oxygen generation and non-toxicity [ 84 , 106 , 107 ].…”

“…Reaction occurs through light-initiated intramolecular processes with the involvement of the side chain. On the basis of some results, it was established that position 2 of the ribityl chain plays the crucial role [ 31 , 36 ] in a typical photodegradation process, according to the model proposed by some authors [ 37 , 38 ], via reduction, dealkilation and addition processes. Thus, the flavin molecule devoid of hydroxyl substituents in the exocyclic chain is unable to react, and photolysis leads to the other photoproducts [ 36 ].…”

“…On the basis of some results, it was established that position 2 of the ribityl chain plays the crucial role [ 31 , 36 ] in a typical photodegradation process, according to the model proposed by some authors [ 37 , 38 ], via reduction, dealkilation and addition processes. Thus, the flavin molecule devoid of hydroxyl substituents in the exocyclic chain is unable to react, and photolysis leads to the other photoproducts [ 36 ]. The photodegradation processes are also suppressed when a flavin molecule is esterificated in a side chain [ 32 ].…”

Quantification of cellular phototoxicity of organelle stains by the dynamics of microtubule polymerization

“…Most of the existing methods to quantify cellular toxicity rely on measuring collective cell responses at later stages. For example, the phototoxicity of dyes to live cells is often quantified using cell viability assays such as 3T3 neutral red uptake, MTT, alamarBlue, or lactate dehydrogenase (LDH) release after illumination (5)(6)(7)(8). Apoptosis and necrosis assays can also be utilized (9).…”