Equisetum telmateia Ehrh. (great horsetail) belongs to the Equisetaceae family and its aerial parts have been traditionally used for skin conditions and to achieve healthy and resilient skin, nails, and hair. This study aimed to evaluate the inhibition of skin-related enzymes by, the antioxidant capacity of, and the phytochemical composition of E. telmateia. Additionally, a novel emulgel was formulated from the main methanolic extract and characterized in terms of pH, viscosity, determination of content quantification, textural profile analysis, and spreadability. After the characterization studies, in vitro release and ex vivo permeation and penetration studies were performed. Firstly, the dried aerial parts of E. telmateia were macerated in methanol, followed by partitioning with solvents of increasing polarity: n-hexane, chloroform, ethyl acetate, and n-butanol. Antioxidant activity was assessed using DPPH, FRAP, CUPRAC, and TOAC assays, while enzyme inhibition was analyzed for collagenase, elastase, hyaluronidase, and tyrosinase. LC-MS/MS analysis identified 53 phytochemical compounds. Protocatechuic acid, the main phenolic compound, was quantitatively analyzed in each subfraction by HPTLC. The in vitro release studies showed sustained release of the reference substance (protocatechuic acid) and the kinetic modeling of the release was fitted to the Higuchi model. The ex vivo permeation and penetration studies showed that the formulation exhibited a retention of 3.06 ± 0.21 µg.cm⁻² after 24 h, whereas the suspended extract demonstrated a skin retention of 1.28 ± 0.47 µg.cm⁻². Both the extracts and the formulated emulgel exhibited inhibitory effects on skin-related enzymes. Our finding suggested that E. telmateia might be a valuable ingredient for wrinkle care and skin-regenerating cosmetics.

Phlomis L., with more than 100 species belonging to the Lamiaceae family, is a genus encompassing a diverse group of plants known for their rich phytochemical profiles and important medicinal properties. Phlomis kurdica Rech. fil. is a member of this genus widely distributed in the Middle East, especially in Iran, Iraq and Türkiye. In traditional medicine, Phlomis species have been employed in the treatment of various disorders, particularly skin conditions such as wound healing, as well as diabetes, hemorrhoids, inflammation, and gastric ulcers. The purpose of this study was to investigate the biological activities of Phlomis kurdica on skin-related enzymes and to evaluate its phytochemical properties using HPTLC, LC-MS/MS. Additionally, an emulgel formulation was developed with methanolic extract of the plant and characterized in terms of spreadability, textural profile analysis, pH, viscosity, and content quantification determination. In vitro release and rheology studies were carried out following the characterization investigations. According to our investigations, P. kurdica may be a useful component of wrinkle prevention and skin-regenerating products.