Insight into the Various Approaches for the Enhancement of Bioavailability and Pharmacological Potency of Terpenoids: A Review

Terpenoids are naturally occurring secondary metabolites that consist of isoprene units (i.e., 2-methyl-1,3-butadiene). Terpenoids became recognized because of their diverse pharmacological benefits, such as anti-cancer, anti-inflammatory, antioxidant, analgesic, antibacterial, antifungal, hepatoprotective, antiviral, and antiparasitic activities. But most of these compounds have limited lipophilicity, dissolution rate, aqueous solubility, and drug permeability, so they are not used effectively. The low bioavailability significantly interferes with the performance of terpenoids to cure diseases, and the absorption process of terpenoids also becomes disrupted; therefore, their bioavailability in the blood becomes insufficient to achieve optimal treatment activity. Thus, to overcome this limitation, some strategies are used, such as nanotechnology (nanoparticles, carrier complexation), cocrystal, and glycosylation. Thus, this review summarizes the chemistry of terpenoids, factors that limit the bioavailability of terpenoids, and strategies employed to date with their design principles and outcomes possibly increasing their bioactivity.