Characterization of Sunflower Oil Extracts from the Lichen Usnea barbata

Abstract

The increasing global emergence of multidrug resistant (MDR) pathogens is categorized as one of the most important health problems. Therefore, the discovery of novel antimicrobials is of the utmost importance. Lichens provide a rich source of natural products including unique polyketides and polyphenols. Many of them display pharmaceutical benefits. The aim of this study was directed towards the characterization of sunflower oil extracts from the fruticose lichen, Usnea barbata. The concentration of the major polyketide, usnic acid, was 1.6 mg/mL extract as determined by NMR analysis of the crude mixture corresponding to 80 mg per g of the dried lichen. The total phenolics and flavonoids were determined by photometric assays as 4.4 mg/mL (gallic acid equivalent) and 0.27 mg/mL (rutin equivalent) corresponding to 220 mg/g and 13.7 mg/g lichen, respectively. Gram-positive (e.g., Enterococcus faecalis) and Gram-negative bacteria, as well as clinical isolates of infected chickens were sensitive against these extracts as determined by agar diffusion tests. Most of these activities increased in the presence of zinc salts. The data suggest the potential usage of U. barbata extracts as natural additives and mild antibiotics in animal husbandry, especially against enterococcosis in poultry.

Antioxidant, Cytotoxic, and Rheological Properties of Canola Oil Extract of Usnea barbata (L.) Weber ex F.H. Wigg from Călimani Mountains, Romania

“…Li et al (2014) [ 42 ] described a green oleo-extraction of natural volatile and non-volatile bioactive compounds from rosemary leaves with 12 refined vegetable oils (soybean, grapeseed, rapeseed, peanut, sunflower, olive, avocado, almond, apricot, corn, wheat germ, and hazelnut oils) and optimized them [ 62 ]. The U. barbata oil extraction was adapted from the simple and low-cost method presented by Bassiouni et al [ 52 ]. They used 1000 mL sunflower oil; however, we opted for only 500 mL cold-pressed canola seed oil to approximately 20 g ground lichen.…”

“…In their previous study, Bassiouni et al (2020) [ 52 ] prepared sunflower oil extract from U. barbata originated from Mexico; they determined UA content by 1 H-NMR spectroscopy and compared its value with the one of a commercial U. barbata supercritical CO 2 extract dissolved in sunflower oil. In addition, they comparatively investigated the antibacterial effects (on bacterial strains isolated from poultry) and the cytotoxic potential (on human tumor cell lines) of U. barbata sunflower oil extract and its previously obtained zinc salt precipitate.…”

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

“…Usnic acid is an extensively studied lichen metabolite with controversial [ 26 , 27 ] results related to its benefits in relationship with the extraction method and the lichen species [ 28 ]. It was used to induce human weight loss [ 29 ], although unwanted hepatotoxic effects were also triggered [ 30 ].…”

Elemental Analysis and In Vitro Evaluation of Antibacterial and Antifungal Activities of Usnea barbata (L.) Weber ex F.H. Wigg from Călimani Mountains, Romania

“…As a representative of the Usnea genus, U. barbata has been used for thousands of years to treat various diseases, including infectious ones [ 36 ]. Its phytochemical profile [ 37 ] displays bioactive secondary metabolites as specific phenolic compounds (depsides and depsidones), dibenzofurans (usnic acid) [ 38 , 39 ], and diphenyl ethers [ 40 , 41 ]; various representatives of these structural categories proved to have significant antibacterial and antifungal properties.…”