Solid Lipid Nanoparticles and Nanostructured Lipid Carriers of natural products as promising systems for their bioactivity enhancement: The case of essential oils and flavonoids

Abstract Natural products are an invaluable source of diverse structures distinguished for their significant therapeutic potential. Specifically, essential oils (EO) are natural, complex liquids presenting various biological activities, such as antioxidant, antimicrobial and antifungal. Flavonoids are natural compounds with multiple pharmaceutical properties. The hydrophobicity and sensitivity of flavonoids and EOs, along with the high volatility of EOs impede their pharmaceutic, cosmetic and food applications, Thus, their encapsulation in a variety of carriers, in an effort to increase their bioavailability and stability is being sought out as a solution to the above problems. Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs) are very promising drug delivery systems used for the controlled release and the effective protection of bioactive substances from external conditions, while presenting low toxicity and excellent biodegradability. This review covers the latest research on the encapsulation of essential oils and 10 different flavonoids in SLNs and NLCs, focused on the improvement of their biological responses and their potent applications.