Exploring Upcycled Cosmetic Raw Materials to Support Sunscreen Formulations

ABSTRACT Sunscreens are regulated as over-the-counter drugs in the United States (US) and contain organic and/or inorganic ultraviolet (UV) filters to reduce the harmful effects of UV radiation, including sunburn, photoaging, and carcinogenesis. However, formulators face significant limitations due to the narrow selection of Food and Drug Administration (FDA)-approved UV filters, many of which raise concerns regarding human safety, environmental toxicity, poor aesthetics, and limited consumer acceptance. At the same time, consumer demand for sustainable and naturally derived cosmetic products has increased interest in upcycled raw materials, yet their potential as photoprotective agents remains largely unexplored. In this study, we evaluated the UV absorption, antioxidant activity, and photostability of five upcycled plant extracts: Picea mariana (Black Spruce) bark (E1), Acer rubrum (Red Maple) bark (E2), Theobroma cacao (Cocoa) husk (E3), Passiflora edulis (Passion Fruit) seed cake (E4), and Lepidium meyenii (Maca) leaf (E5). Extracts demonstrated variable UV absorption profiles, with E3 exhibiting the strongest in vitro SPF value (25.28 ± 0.05) and highest photostability. Antioxidant assays revealed potent radical scavenging activity for E2 and E3, whereas E4 and E5 were weaker. When incorporated into gel and cream formulations, the extracts produced modest SPF enhancement compared to vehicles but remained significantly less effective than FDA-approved filters. These findings suggest that while upcycled extracts cannot replace conventional UV filters, they may serve as multifunctional additives that contribute antioxidant activity and/or modestly extend UV coverage.