From plants to phospholipid vesicles: A comprehensive review on the incorporation of phytochemicals into phospholipid vesicles designed for skin applications with special focus on scalability and in vitro and in vivo efficacy

Natural bioactives, especially those derived from plants, have gained a great popularity throughout the scientific community and among the final users, as they are considered an ideal alternative to synthetic drugs to prevent chronic diseases and treat minor affections, especially at skin level. To substantiate their activities, different plant-derived molecules and extracts have been tested, mainly in vitro. In addition, in the last decades, several studies have been centred on their incorporation into innovative and effective nanocarriers aiming at improving their beneficial properties upon application on the skin. Among the proposed nanocarriers, phospholipid vesicles appeared to be the most effective thanks to their ability to interact with the skin components and reach the deeper strata, along with their high biocompatibility and feasibility. This review aims at providing a comprehensive analysis of the studies performed on phospholipid vesicles as topical carriers for plant-derived bioactive molecules. The different formulations tested have been reported and discussed along with the different techniques used for their preparation, with special attention to low dissipative, environmentally friendly and scalable methods. Moreover, the in vitro and in vivo performances of obtained formulations have been analysed. Interesting opportunities and challenges for the integrated utilisation of these natural formulations are proposed as well.