Antioxidant and UV-protective evaluation of tocochromanols in nanoformulations

Tocochromanols, a group of compounds widely present in plant oils and commonly used in cosmetic formulations, exhibit varying photostability under UV irradiation. In this study, we investigated the photostability and potential UV-protective properties of several tocochromanol homologues (α-tocopherol, γ-tocopherol, γ-tocotrienol and plastochromanol-8) both in free form and encapsulated within liposomal and niosomal carriers. Our findings demonstrated that α-tocopherol, despite its widespread use in sunscreens, was the least stable under UV exposure. In contrast, γ-tocopherol, γ-tocotrienol and plastochromanol-8 showed significantly higher stability, particularly when encapsulated in liposomes, maintaining antioxidant activity even after prolonged UV irradiation. HPLC analysis confirmed a pronounced degradation of α-tocopherol upon UV exposure, while other homologues were less affected. Furthermore, encapsulation enhanced the calculated SPF values, with the highest protection observed for γ-tocopherol and plastochromanol-8 in liposomes. These results suggest that non-α- tocochromanol forms offer promising potential as effective and stable components in UV-protective formulations. This research highlights the importance of further exploring the diverse roles of tocochromanols in photoprotection, especially given their natural abundance in plant-derived cosmetic ingredients.