Encapsulation of Lavandula austroapennina N.G. Passal., Tundis & Upson extracts: Focus on leaf and stem enriched liposome for cosmeceutical innovation

Abstract

In the framework aimed at valorizing Lavandula austroapennina N.G. Passal., Tundis & Upson, an endemic species of the Apennine mountains of southern Italy, through the deep investigation of its organ chemical composition and bioactivity, innovative cosmeceutical applications are of interest. Thus, lipophilic and alcoholic extracts, at dose levels avoiding cytotoxicity in keratinocytes, were encapsulated into liposomes by applying thin-film hydration method. This was aimed to overcome known plant extract issues, such as poor solubility, high instability, and low skin permeation. The lipid-based vesicles were characterized by particle size dimension ≤300 nm, negative charge (-8 to −20 mV) and polydispersity index <0.3. Entrapment efficiency distinguished liposomes encapsulating alcoholic extracts from corolla- and calyx for their highest flavonoids, while those with leaf- and root alcoholic extracts excelled in phenolic acids and their conjugates. Among lipophilic extracts, those from corolla, calyx and stem provided liposomes entrapping the highest lipid content. These data, together with the greater bioactivity of alcoholic leaf, and lipophilic stem extract, allowed us to further investigate these two extracts for their cosmeceutical applicability. Accordingly, extracts-containing liposomes, preliminarily characterized by ATR-FTIR spectroscopy, underwent cytotoxic and healing capability assessment towards HaCaT cells. The extracts-enriched liposomes showed a healing capacity higher than the parental extracts from which they derived. Evaluating the percutaneous absorption by Franz Cells assay, followed by UHPLC-QqTOF-HR-MS-based quali-quantitative analysis, revealed that encapsulation in liposomes improved bioactive delivery through/into a specific skin layer. These results, while suggesting the effectiveness of liposome-based nanoparticles in improving the bioavailability and biological activity of specialized metabolites, reinforce the cosmeceutical use of L. austroapennina extracts.