Application and Development of Natural Plant Metabolite Oleanolic Acid in the Nano Era

Like other pentacyclic triterpenoids, oleanolic acid, a natural plant metabolite prevalent in plant peels, stems, and leaves, is regarded as a possible drug candidate. A growing number of studies have shown that oleanolic acid exhibits a variety of beneficial properties, including antiviral, anti-inflammatory, antioxidant, anticancer, and hepatoprotective effects. Additionally, the rapid advance of nanotechnology has dramatically improved oleanolic acid’s bioavailability and minimized its disadvantages, leading to unexpected changes in its pharmacological activity and use. Therefore, our aim was to review the progress of research on the distribution and biological properties of oleanolic acid in plants and to discuss new pharmaceutical approaches for oleanolic acid.