Usnic acid biological activity: history, evaluation and usage

Abstract

Since Usnic acid (UA) was isolated from lichen metabolite in 1844, a lot of studies were conducted on it and now it became commercially available in the market. Its wide availability in different lichen species, being isolated easily, and high purity of the isolated product make it an excellent base for producing new pharmaceuticals. In this review the different usage of UA was summarized. It was utilized as an antioxidant, anti-proliferative, antimicrobial and antiprotozoal, larvicidal and insecticidal, antifungal, antiviral, algicidal, anti-inflammatory, pain-relieving and antipyretic agent. Many adverse effects were associated with using usnic acid, especially at high dose, including; hepatotoxicity, genotoxicity, allergenicity, side effects on the cardiovascular system and adipocytes of fatty tissue. This review aimed to throw the light on the updated biological activities, effectiveness and safety and usage of usnic acid during the last decade.

Cladonia uncialis as a valuable raw material of biosynthetic compounds against clinical strains of bacteria and fungi

“…The antibacterial activity of C. uncialis extracts has been proven for the first time in our previous studies, in which we demonstrated a high activity of the C. uncialis acetone extract (CUE) on methicillin-resistant Staphylococcus aureus (MRSA) strains (Studzińska-Sroka et al, 2015). These interesting findings, as well as previous information about antimicrobial activity of UA (Galanty et al, 2012;Alahmadi et al, 2017;Galanty et al, 2019), prompted us to expand the study on the activity of CUE against clinical pathogenic strains responsible for skin and wound infections, which demonstrate resistance to antibiotics. In our research we also compared the cytotoxic effect of the tested substances by employing in vitro studies with human keratinocyte cell cultures (HaCaT).…”

“…Most of studies on antibacterial activity of UA were focused on its (+) enantiomer, which usually demonstrated an increased activity in comparison to its (-) form (Galanty et al, 2012). In addition to antibacterial properties, UA has also antioxidant, antiproliferative, antiprotozoal, larvicidal and insecticidal, antifungal, antiviral, algicidal, anti-inflammatory, pain-relieving and antipyretic properties, as has been demonstrated by in vivo and in vitro studies (Alahmadi, 2017).…”

Antioxidant and Cytotoxic Activities of Usnea barbata (L.) F.H. Wigg. Dry Extracts in Different Solvents

“…Lethality and cytological changes in brine shrimp larvae are easy to assess in these organisms [ 54 ], making screening very fast and efficient. A study on liver cells [ 55 ] showed an increase in lipid droplet content and fragmentation of the endoplasmic reticulum in conditions of exposure to usnic acid. We consider these cytological aspects similar to those observed in the organisms exposed in UBDE ( Figure 5 b–e).…”

Usnic Acid and Usnea barbata (L.) F.H. Wigg. Dry Extracts Promote Apoptosis and DNA Damage in Human Blood Cells through Enhancing ROS Levels

“…The metabolomics of this species belongs to different classes of chemical compounds: depsides (barbatic acid, methyl-8-hydroxy-4- O -demethylbarbatate, baeomycesic acid, 8-hydroxybarbatic acid), depsidones (connorstictic acid, fumarprotocetraric acid, hypoconstictic acid, lobaric acid), lipids (polyhydroxylated lipids), and dibenzofurans (usnic acid, placodiolic acid) [ 21 ]. Of all these lichen secondary metabolites, usnic acid [ 22 ] is by far the best known [ 23 ] and responsible for most bio-activities [ 24 ] of the U. barbata and, at the same time, of all lichens of the Usnea genus [ 25 ].…”