Photochemical Reactions of Riboflavin in Aqueous Systems

Riboflavin (vitamin B2) in aqueous solution exhibits a rich photochemistry driven by absorption in the near-UV and visible regions. Photon absorption populates singlet excited states that may intersystem cross to form longer-lived triplet states capable of transferring energy to molecular oxygen or substrates. Two principal photochemical pathways are observed: a Type I mechanism involving electron or hydrogen transfer to form reactive oxygen species (ROS) such as superoxide and hydrogen peroxide, and a Type II mechanism yielding singlet oxygen. These processes lead to the formation of characteristic photoproducts including lumichrome and lumiflavin, with kinetics strongly dependent on pH, buffer composition, ionic strength and oxygen concentration. Photodegradation of riboflavin has implications for its stability in food and pharmaceutical formulations, while controlled ROS generation underpins its role as a photosensitiser in disinfection and photodynamic therapy. Recent advances have deepened understanding of excited-state dynamics, photoproduct identification and strategies to modulate pathways through complexation and molecular derivatisation, thereby widening applications from biomedicine to environmental remediation.

Research from Nature Portfolio

Foundational investigations have clarified the fundamental photophysical behaviour of flavins in aqueous media. Studies of riboflavin and flavin mononucleotide adsorbed onto cellulosic fabrics revealed absorption peaks at 270 nm, 370 nm and 446 nm, quantified quantum yields under varying pH and demonstrated strong photoluminescence and UV-protective properties. In parallel, the development of a sequence-specific RNA photocleavage method employed unmodified DNA oligonucleotides paired with riboflavin to exploit a G•U wobble in the duplex; visible-light activation generated ROS that induced controlled oxidative elimination of the target strand. Together, these works have mapped excited-state lifetimes, elucidated energy and electron transfer pathways, and provided precise spatiotemporal control over photochemical reactivity in both material and biological contexts.

Photochemical Reactions of Riboflavin in Aqueous Systems publication trend

The graph below shows the total number of articles in photochemical reactions of riboflavin in aqueous systems across all publications each year (not limited to Nature Index journals).

Technical terms

Singlet oxygen: an electronically excited form of molecular oxygen with paired spins, generated via energy transfer from an excited sensitiser.

Reactive oxygen species: chemically reactive molecules derived from oxygen, including superoxide, hydrogen peroxide and hydroxyl radicals.

Quantum yield: the efficiency of a photochemical process defined as the number of events (e.g. photon emissions, product formations) per photon absorbed.

Photodegradation: the breakdown of a compound induced by the absorption of light, often leading to structural modification and loss of function.

Photosensitiser: a molecule that absorbs light and transfers energy or electrons to substrates or oxygen to initiate photochemical reactions.

References

1. A H2O2‐Supplied Supramolecular Material for Post‐irradiated Infected Wound Treatment. Advanced Science (2023).
2. Riboflavin and Its Derivates as Potential Photosensitizers in the Photodynamic Treatment of Skin Cancers. Cells (2023).
3. Photo, thermal and chemical degradation of riboflavin. Beilstein Journal of Organic Chemistry (2014).
4. Study of photoluminescence property on cellulosic fabric using multifunctional biomaterials riboflavin and its derivative Flavin mononucleotide. Scientific Reports (2019).
5. Sequence-specific RNA Photocleavage by Single-stranded DNA in Presence of Riboflavin. Scientific Reports (2015).
6. Gas-permeable liquid-core waveguide coupled to LC-MS for studying the influence of oxygen on photodegradation processes. Journal of Photochemistry and Photobiology A Chemistry (2023).