Cosmeceutical Potential of Matcha (Camellia sinensis) and Yerba Mate (Ilex paraguariensis) Extracts Obtained with Green Solvents

Matcha (Camellia sinensis) and yerba mate (Ilex paraguariensis) are polyphenol-rich plants of growing interest for cosmetic applications, yet the influence of green extraction solvents on their cosmeceutical potential remains underexplored. In this study, aqueous, 20% (v/v) ethanol (EtOH) and 50% (v/v) propylene glycol (PG) extracts of both raw materials were prepared by ultrasound-assisted extraction and compared in terms of total phenolic and flavonoid content, antioxidant activity (DPPH and ABTS), tyrosinase inhibition, in vitro sun protection factor (SPF) and cytotoxicity towards human BJ fibroblasts and A375 melanoma cells. Phytochemical profiles were characterized by HPLC-ESI-QTOF-MS/MS, and phytochemistry–activity relationships were explored using hierarchical clustering, Czekanowski analysis and PCA-based regression modeling with leave-one-out cross-validation. Both botanical origin and extraction solvent markedly shaped the composition and biological activity of the extracts, and neither was universally optimal. The matcha 50% PG extract emerged as a promising ready-to-use extract for brightening- and photoprotection-oriented applications, combining strong tyrosinase inhibition with the highest in vitro SPF among the matcha preparations, whereas aqueous and ethanolic extracts showed stronger DPPH scavenging and the most favorable fibroblast safety. For yerba mate, the aqueous and ethanolic extracts were more cytotoxic towards A375 melanoma cells than the PG extract, suggesting a distinct application niche. Chemometric modeling linked biological responses to multivariate phytochemical patterns rather than single compounds, providing marker sets to guide green-solvent extract optimization and cosmetic formulation.