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

Abstract

Usnea genus (Parmeliaceae, lichenized Ascomycetes) is a potent phytomedicine, due to phenolic secondary metabolites, with various pharmacological effects. Therefore, our study aimed to explore the antioxidant, cytotoxic, and rheological properties of Usnea barbata (L.) Weber ex F.H. Wigg (U. barbata) extract in canola oil (UBO) compared to cold-pressed canola seed oil (CNO), as a green solvent used for lichen extraction, which has phytoconstituents. The antiradical activity (AA) of UBO and CNO was investigated using UV-Vis spectrophotometry. Their cytotoxicity was examined in vivo through a brine shrimp lethality (BSL) test after Artemia salina (A. salina) larvae exposure for 6 h to previously emulsified UBO and CNO. The rheological properties of both oil samples (flow behavior, thixotropy, and temperature-dependent viscosity variation) were comparatively analyzed. The obtained results showed that UBO (IC50 = 0.942 ± 0.004 mg/mL) had a higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than CNO (IC50 = 1.361 ± 0.008 mg/mL). Both UBO and CNO emulsions induced different and progressive morphological changes to A. salina larvae, incompatible with their survival; UBO cytotoxicity was higher than that of CNO. Finally, in the temperature range of 32–37 °C, the UBO and CNO viscosity and viscoelastic behavior indicated a clear weakening of the intermolecular bond when temperature increases, leading to a more liquid state, appropriate for possible pharmaceutical formulations. All quantified parameters were highly intercorrelated. Moreover, their significant correlation with trace/heavy minerals and phenolic compounds can be observed. All data obtained also suggest a possible synergism between lichen secondary metabolites, minerals, and canola oil phytoconstituents.

Phenolic Secondary Metabolites and Antiradical and Antibacterial Activities of Different Extracts of Usnea barbata (L.) Weber ex F.H.Wigg from Călimani Mountains, Romania

“…The low yields associated with diminished UAC in dried lichen can also be observed in other studies on U. barbata extracts obtained in various conditions [ 42 , 43 , 53 , 54 ]. The most relevant data are displayed in Table 8 .…”

“… UB SFE— U. barbata extract obtained by supercritical fluid extraction with CO 2 , UBDEA— U. barbata dry extract in ethyl acetate, UBDA— U. barbata dry extract in acetone, UBDE— U. barbata dry extract in ethanol, UBDM— U. barbata dry extract in methanol, UBO— U. barbata extract in canola oil, RM—roller mill; UM—ultra-centrifugal mill; CM—cutting mill; RGD—rapid gas decompression. * Data registered in decreasing order; superscript letters evidenced the data adapted from: a [ 53 ], b [ 42 ], c [ 54 ], d [ 43 ]. …”

Evaluation of Usnea barbata (L.) Weber ex F.H. Wigg Extract in Canola Oil Loaded in Bioadhesive Oral Films for Potential Applications in Oral Cavity Infections and Malignancy

“…The U. barbata extract in canola oil (UBO) was obtained using a method adapted from that described by Basiouni et al [ 29 ], from 20.2235 g dried and ground lichen and 500 mL cold-pressed canola seed oil [ 26 ] in darkness, at room temperature (21–22 °C). The container with both components was shaken daily for three months; then, UBO was filtered in another brown vessel with a sealed plug and preserved in a plant room, sheltered from sun rays.…”

“…The larvae were obtained from A. salina cysts through continuous light and aeration in a 0.35% saline solution at 20 °C. The brine shrimp larvae in the first stage (instar I) were introduced in 0.3% saline solution into experimental pots (with a volume of 1 mL) [ 26 ]. The analysis was compared to a blank (untreated nauplii) to obtain accurate results regarding the F-UBO cytotoxic effect.…”

“…Most authors have used chemical solvents for the preparation of these lichen extracts: ethanol, methanol, acetone, ethyl acetate, dimethyl ether, CCl 4 , hexane, and CO 2 supercritical [ 22 , 23 , 24 ]. We propose to explore the properties of U. barbata extract in a green solvent—canola oil [ 25 , 26 ].…”