Phytochemical Analysis, Antioxidant, Antimicrobial, and Cytotoxic Activity of Different Extracts of Xanthoparmelia stenophylla Lichen from Stara Planina, Serbia

Abstract

The aim of this study was to identify some of the secondary metabolites present in acetonic, methanolic, and hexanic extracts of lichen Xanthoparmelia stenophylla and to examine their antioxidant, antimicrobial, and cytotoxic activity. Compounds of the depsid structure of lecanoric acid, obtusic acid, and atranorin as well as usnic acid with a dibenzofuran structure were identified in the extracts by HPLC. The acetone extract was shown to have the highest total phenolic (167.03 ± 1.12 mg GAE/g) and total flavonoid content (178.84 ± 0.93 mg QE/g) as well as the best antioxidant activity (DPPH IC50 = 81.22 ± 0.54). However, the antimicrobial and antibiofilm tests showed the best activity of hexanic extract, especially against strains of B. cereus, B. subtilis, and S. aureus (MIC < 0.08, and 0.3125 mg/mL, respectively). Additionally, by using the MTT method, the acetonic extract was reported to exhibit a strong cytotoxic effect on the HeLa and HCT-116 cell lines, especially after 72 h (IC50 = 21.17 ± 1.85 and IC50 = 21.48 ± 3.55, respectively). The promising antioxidant, antimicrobial, and cytotoxic effects of Xanthoparmelia stenophylla extracts shown in the current study should be further investigated in vivo and under clinical conditions.

Methodological Aspects of Green Extraction of Usnic Acid Using Natural Deep Eutectic Solvents

“…The values of the LogP coefficient (2.88) [ 12 ] and topological polar surface area (118 Å 2 ) [ 13 ] evidence the lipophilic nature of this compound, which largely determines its poor solubility in polar solvents. For this reason, UA is extracted from lichens using solvents such as acetone [ 5 , 10 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], dichloromethane [ 21 , 22 , 23 , 24 ], petroleum ether [ 3 , 4 , 25 ], n-hexane [ 26 ], and heptane [ 27 ]. Methanol and ethanol are also used as solvents, although much less frequently [ 4 , 28 , 29 ], as their extraction yields are lower than those of non-polar solvents.…”

Evaluation of In vitro Anticancer Activity (Ovarian Cancer Cells-pa1) and Zebrafish Embryo Toxicity of Parmelia perlata Ethanolic Extract

“…Using the standard procedure of [8,10,11], the plant extract was analyzed for the presence of various phytochemicals in the ethanolic extract of P. perlata.…”

“…The radical scavenging activity of P. perlata was assessed using the DPPH assay [8][9][10][11][12]. A 1 mL solution of DPPH (0.1 mM) was combined with 3 mL of P. perlata extract at various concentrations (10-50μg/ml).…”

“…The ethanolic extract of P. perlata was tested against pathogenic bacterial strains such as Escherichia coli, Staphylococcus aureus, Enterococcus sp., Bacillus subtilis, Klebsiella pneumoniae, and Pseudomonas sp. Antibacterial activity was assessed using the standard agar well diffusion method [8,11]. Different concentrations of the ethanolic P. perlata extract (50, 100, and 150 µg/ml) were prepared using 2% DMSO (dimethyl sulfoxide).…”

“…Lichens are intricate symbiotic partnerships consisting of fungi, known as "mycobionts," and one or more algae or cyanobacteria, referred to as "photobionts." P. perlata is a frequently found lichen that is frequently observed on well-lit surfaces of rocks, belonging to the Parmeliaceae family [8]. In earlier times, lichen was used to treat sexually transmitted diseases like syphilis, reduce inflammation in the gum tissue, and provide relief from disorders such as arthritis, rheumatism, swelling, and heavy menstrual bleeding.…”