Comparing conventional and sustainable solvents for plant-based cosmetic bioactives: from extraction to application

Natural cosmetics are gaining prominence in the market, making the efficient and safe extraction of bioactive compounds essential. This review, based on more than 130 articles retrieved from reliable databases, analysed the importance of selecting the safest and most efficient extracting liquid for cosmetic applications. Traditional solvents such as methanol and hexane have been used less frequently in human applications due to toxicity, which affects both use and disposal when separated from the target molecule. As an alternative, interest in green solvents, such as deep eutectic solvents (DES) and ionic liquids (ILs), is increasing. These solvents offer sustainability advantages but may also present challenges due to complexity, requiring further study. In cosmetic formulations, the multifunctionality of glycols allows their use as extraction liquids or as vehicles for resuspending dried extracts. Understanding plant composition is crucial for selecting the most suitable extraction liquid, ensuring effective isolation of bioactive compounds for cosmetic applications.