Nano- and Microcarriers as Drug Delivery Systems for Usnic Acid: Review of Literature

Abstract

Usnic acid is one of the most investigated lichen secondary metabolites, with several proven biological properties with potential medical relevance. However, its unfavorable physico-chemical properties, as well as observed hepatotoxicity, have discouraged wide-range utilization of usnic acid as a promising therapeutic agent. In accordance with the growing research interest in the development of nanotechnology, especially in the arena of preparations based on natural sources of medicinal compounds, usnic acid incorporated into nano- and microsized colloidal carriers has been a subject of a large number of publications. Therefore, this review discusses the overall results of the studies dealing with usnic acid encapsulated into lipid-based, polymeric and nonorganic micro- and/or nanocarriers, as potential drug delivery systems for this natural compound, in an attempt to introduce its usage as a potential antitumor, antimicrobial, wound-healing, antioxidative and anti-inflammatory drug.

Synergistic Effect between Usnic Acid and Polymyxin B against Resistant Clinical Isolates of Pseudomonas aeruginosa

“…There are limitations regarding the use of usnic acid in in vivo models of systemic infections, due to its low aqueous solubility and hepatotoxicity after systemic administration [ 40 ]. Therefore, investigations on the therapeutic use of usnic acid in vivo have been focused on the topical application of this compound, especially in the treatment of infected wounds [ 19 , 40 , 41 ]. The study conducted by Zhang et al [ 41 ] demonstrated through histopathological analyses that usnic acid had a healing effect in rats after its topical application.…”

“…ere are limitations regarding the use of usnic acid in in vivo models of systemic infections, due to its low aqueous solubility and hepatotoxicity after systemic administration [40].…”

“…erefore, investigations on the therapeutic use of usnic acid in vivo have been focused on the topical application of this compound, especially in the treatment of infected wounds [19,40,41]. e study conducted by Zhang et al [41] demonstrated through histopathological analyses that usnic acid had a healing effect in rats after its topical application.…”

“…An alternative strategy to reduce usnic acid's side effects is its encapsulation into drug delivery systems [40]. Some studies have already proposed the encapsulation of the acid into liposomes and evaluated its potential in in vitro experiments.…”

Docking Studies of Usnic Acid and Sodium Usnate on SARS CoV-2 Main Protease and Spike Protein RBD

“…It has been demonstrated that usnic acid inhibits inflammatory response and prooxidant damage in pulmonary tissue mice infected with pulmonary fibrosis as a therapeutic against pulmonary disease [16]. Studies on usnic acid encapsulated into lipid-based, polymeric and non-organic micro-and/or nanocarriers, as potential drug delivery systems are some efforts are in process to overcome its limitations [12,20]. Table 1 shows molecular structure, molecular weight and rotatable bonds of ligands used to dock with SARS CoV 2 protein and follows Lipinski's rule.…”