Current Overview of Cyclodextrin Inclusion Complexes of Volatile Oils and their Constituents

Background: Volatile oils and their constituents have been considered major bioactive natural compounds due to their wide therapeutic and biological activities in pharmaceuticals in human healthcare. However, due to their poor solubility, their applications are limited. The inclusion complexation of volatile oils and their volatile constituents with cyclodextrins has emerged as a promising approach for the improvement of aqueous solubility, bioavailability, and stability. Objective: The present review summarizes various research investigations highlighting the complexation of volatile oils and their constituents with cyclodextrins and their derivatives. Additionally, we present an overview of patents published between 1998-2021 to highlight the significance of including volatile oil in cyclodextrins. Methods: The selection of articles for the current review was carried out by using keywords ‘Cyclodextrin’, ‘Essential oil’, ‘Inclusion Complex’, ‘Encapsulation’ and ‘Essential oils/ volatile oils constituents’ in certain specific databases, such as Elsevier (Science Direct), Pubmed Medical subject headings (MeSH) and Medline. Results: A total of 199 studies published were included in the review. In vitro and in vivo studies revealed the efficacy of EOs and their VCs complexed with various types of CD compared to free forms. Conclusion: This review shows the impact of cyclodextrin complexation on the solubility, bioavailability, stability, and biological activities of volatile oils and their constituents.