Annatto (Bixa orellana)-Based Nanostructures for Biomedical Applications-A Systematic Review

Plants are a source of valuable organic chemical compounds with complex structures rich in therapeutic activities. The encapsulation of compounds in nanostructured systems is an alternative to avoid limitations, such as instability and low solubility, and to promote therapeutic use. The objective of the present review was to summarize the data in the literature on the physicochemical characteristics, biomedical efficacy, and toxicity of nanostructures containing extracts and oils obtained from annatto (Bixa orellana). For this, searches were conducted in the CINAHL, LILACS, Embase, FSTA, MEDLINE, ProQuest, PubMed, ScienceDirect, Scopus, and Web of Science databases. Studies that carried out the development, physical-chemical characterization, and evaluation of therapeutic efficacy and/or in vitro, in vivo, or clinical toxicity of nanostructures containing extracts and oils derived from annatto were included in the review. Of the 708 articles found, nine met the inclusion criteria. The included studies developed different nanostructures (nanofibers, nanocochleates, chitosan, lipid, polymeric, and metallic nanoparticles). These nanostructures showed leishmanicidal, photoprotective, antioxidant, antimicrobial, and immunomodulatory efficacy, and tissue regeneration potential with no or low toxic effects in the tested models. Thus, the present work supports the nanostructuring of annatto extracts and oils as a relevant approach to the development of new technologies for biomedical applications.