A Photoprotective Cosmetic Formulation Assessment Containing a Standardized Extract of Marcetia latifolia

The Marcetia species are well adapted to semi-arid regions and stand out as promising sources of phenolic compounds, including flavonoids, with potential photoprotective properties. The aim of this study was to investigate the photoprotective potential of a standardized extract of Marcetia latifolia leaves for potential application in a sunscreen formulation (UV-A and UV-B). The crude ethanolic extract of M. latifolia leaves (EEML) was standardized to contain 16.48 g of quercetin and 5.23 g of calycopterin per kg of plant and incorporated into a lotion based on Polawax®. The EEML was evaluated for its photoprotective potential by determining its flavonoid content, antioxidant activity, in vitro SPF and toxicity, with a view to its subsequent incorporation into a cosmetic formulation. The extract showed high flavonoid content, combined with relevant antioxidant activity and SPF values (13 and 7.12 at concentrations of 250 and 125 μg/μL, respectively). It also showed UVA photoprotective potential, with only 7.62% degradation of the RVS. In the HET-CAM test, EEML showed low irritant potential (IS: 2.43). The formulations containing the EEML showed satisfactory physicochemical characteristics after organoleptic, centrifugation and spreadability tests. The formulations showed satisfactory SPF and photoprotective performance. These results indicate the feasibility of using the EEML as a sunscreen in pharmaceutical preparations.