Phytochemical Analysis, Cytotoxic, Antioxidant, and Antibacterial Activities of Lichens

Abstract

Background. Lichens present a complex symbiotic relationship between a filamentous fungus, photoautotrophic partner (algae or cyanobacteria), and bacterial community. The Objective of the Study. This study aimed at investigating the chemical composition and cytotoxic, antioxidant, and antimicrobial activities of acetone extracts of Moroccan Evernia prunastri (E. prunastri), Ramalina farinacea (R. farinacea), and Pseudevernia furfuracea (P. furfuracea). Materials and Methods. The phytochemical analysis was carried out by HPLC-UV. The cytotoxic effect was assessed on human prostate cancer (22RV1), human colon carcinoma (HT-29), human hepatocellular carcinoma (Hep-G2), and Hamster ovarian cancer (CHO) cells lines by WST1 assay. The antioxidant power was assessed by DPPH and FRAP assays. The antibacterial effect was obtained using the broth microdilution method. Results. The findings of phytochemical analysis showed that the lichens studied possess interesting bioactive molecules such as physodalic acid, evernic acid, and usnic acid, as well as protocetraric acid. According to the American National Cancer Institute guidelines, the WST-1 test showed that all crude extracts did not show significant cytotoxic effects against all concerous cell lines, and IC50 values ranged from 42.30 to 140.24 µg/mL. Regarding the antioxidant activity, P. furfuracea extract showed the highest free-radical-scavenging ability (IC50 = 498.40 µg/mL). The most potent antibacterial extract was recorded for P. furfuracea extract with a minimum inhibitory concentration (MIC) ranging from 0.039 to 0.31 mg/mL. Conclusion. In this research work, we report that the studied lichen extracts exhibit an important biological effect, supporting that lichens represent a hopeful source of original natural products for the research of new bioactive molecules having a pharmaceutical interest.

Antimicrobial and antioxidant activity of Evernia prunastri extracts and their isolates

“…Extracts from E. prunastri , in the turn, showed moderate antioxidant activity comparing to usnic acid and a lower number of phenols. Obtained results are corresponding to the published ones (Mitrović et al 2011 ; Hawrył et al 2020 ; Aoussar et al 2020 ).…”

“…There is less information about the antimicrobial activity of E. prunastri. An acetone extract from E. prunastri has been published to be active against S. aureus at the concentration range of 0.078-0.5 mg/ml and a MRSA clinical isolate at the concentration of 0.039 mg/ml (Tapalsky et al 2017;Aoussar et al 2020). A methanol extract was active at the concentration of 0.156 mg/ml (Mitrović et al 2011).…”

“…The 50-fold higher MIC was observed when a 50-times higher number of colony-forming units (CFU) was utilizing than for the lower MIC. Different extracts from E. prunastri have been published to be active against P. aeruginosa at concentrations of 2.5-25 mg/ml (Mitrović et al 2011;Aoussar et al 2020). Another publication regarding to acetone extract from E. prunastri described no effect on P. aeruginosa at a concentration below 500 µg/ml (Tapalsky et al 2017).…”

Chemical Composition and In Vitro Antioxidant and Antimicrobial Activities of the Marine Cyanolichen Lichina pygmaea Volatile Compounds

“…In another study, methanolic and ethyl acetate extracts from the lichen Umbilicaria cylindrica demonstrated important antimicrobial activity against eight strains, including S. aureus , E. coli and C. albicans , with MIC values ranging from 15.62 to 62.50 μg/mL [ 34 ]. Other reports indicated that extracts from the two lichens Evernia prunastri and Pseudevernia furfuracea exhibited a higher antibacterial effect vs. five clinical isolates of methicillin-resistant S. aureus , with MIC values of 0.039 to 0.15 mg/mL, and extracts of Ramalina farinacea possessed MIC values in the range of 0.078–0.625 mg/mL [ 35 ]. The antimicrobial effect of LPVC could be explained by the presence of a high level of the sesquiterpene himachalene derivatives, since a positive correlation between these compounds and the antimicrobial activity was proved [ 36 ].…”

Promising Antioxidant and Antimicrobial Potencies of Chemically-Profiled Extract from Withania aristata (Aiton) Pauquy against Clinically-Pathogenic Microbial Strains

“…Briefly, two microbial colonies were collected from a fresh culture after 24 h in Mueller–Hinton agar (MHA) and Sabouraud Agar (SBA) media and then suspended in 0.9% NaCl solution. Subsequently, the suspension turbidity was adjusted to be 0.5 McFarland [ 78 ]. For the mold species, the inoculum was prepared by the conidial suspension.…”