Natural compounds possess significant potential for pharmacological applications. This study investigates melanin derived from birch heartwood polymerized with the mycelium of fungus Fomes fomentarius and its fruiting body, for its potential geroprotective properties. The cytotoxicity and proliferative effects of the studied compound, Amelan, were evaluated using the immortalized human foreskin fibroblasts (BJ-5ta) and human breast adenocarcinoma (MDA-MB-231) cell lines through the MTT assay and cell counting with a Goryaev chamber. To assess the geroprotective properties of the compound, an accelerated aging model was induced with D-galactose in primary human dermal fibroblast cultures. Senescent cell populations were identified through cytochemical staining for senescence-associated β-galactosidase (SA-β-gal). Amelan exhibited a dose-dependent geroprotective effect, significantly reducing senescent cell populations at optimal concentrations. Importantly, the compound did not stimulate proliferation in either immortalized BJ-5ta fibroblasts or MDA-MB-231 cancer cells, suggesting no oncogenic activation potential. In light of the demonstrated geroprotective effects of Amelan, its concentration-dependent efficacy underscores the importance of dosage optimization to maximize therapeutic benefits while minimizing adverse effects. Further research is needed to evaluate its potential as a candidate for anti-aging therapy.

During the clinical use of photobiomodulation (PBM) to manage radiotherapy-induced side effects, tumor tissue may be exposed to low-intensity laser light. Therefore, it is necessary to evaluate potential unintended PBM stimulation of tumor cells when PBM combines with ionizing radiation (IR). We investigated the effects of PBM (0.3 J/cm²) on the cell cycle, mitochondrial potential, and cell death of HeLa Kyoto cells, comparing pre-irradiation (PBM→IR) and post-irradiation (IR→PBM) exposure to 2 Gy, 4 Gy, and 6 Gy of ionizing radiation. PBM prior to IR induced the radiation-induced arrest in the G₂/M phase of the cell cycle. PBM after IR resulted in a partial release of cells from the radiation-induced arrest in the G₀/G₁ phase, along with a decrease in the number of apoptotic cells and cells with depolarized mitochondrial membranes compared to samples treated with IR only. These findings provide a basis for further research into PBM timing to improve radiotherapy outcomes.