Cladonia rangiformis Acetone Extract— New Insight into the Chemical Composition and Biological Activity

Abstract

Introduction Cladonia rangiformis, also known as reindeer lichen, has been used for various remedies in folk medicine. The rich nutritional value of this lichen is reflected in the fact that it contains atranorin, which has been proven to have numerous biological activities. Objective The chemical composition, antioxidant, anticholinesterase, and antigenotoxic activities of the C. rangiformis acetone extract were investigated. The novelty of this work is that anticholinesterase activity, protective effect on human lymphocytes, and antioxidant activity by the cupric-reducing antioxidant capacity (CUPRAC) method of C. rangiformis extract were determined for the first time, as well as gas chromatography - mass spectrometry (GC-MS) profile. Methods Chemical composition was carried out by high-performance liquid chromatography (HPLC)-diode array detector and GC-MS. Antigenotoxic effect was evaluated in human lymphocytes by cytokinesis-block micronucleus assay. Total phenolic content, DPPH and ABTS radical scavenging capacities, CUPRAC, and total reducing power were determined spectrophotometrically. Determination of acetylcholinesterase activity was performed by Ellman's colorimetry assay. The statistical analysis of variance (One-way ANOVA) was performed using Origin software package version 7.0. Results HPLC method was used to identified 3 compounds with atranorin as predominant constituent (97.2%). Fumarprotocetraric and atraric acid were represented in a much smaller mutually approximate amount, 0.3 and 0.5%, respectively. Rangiformic acid was the most abundant volatile compound. Acetone extract of C. rangiformis (2 μg/mL) decreased the frequency of micronuclei by 15.5% while the radioprotectant amifostine reduced the frequency of occurrence of micronuclei by 11.4%. On the contrary, at a concentration of 1.0 mg/mL the extract exhibited an activating effect on cholinesterase (2.0%), while at a concentration of 10.0 mg/mL it showed a weak inhibitory effect (7.3%). The total phenol content was 132.71 μg gallic acid equivalents per mg of dry extract. The IC50 value for the DPPH experiment was 16.19 mg/mL and for ABTS was 11.80 mg/mL. Cupric reducing capacity and total reducing power were 17.81 μg Trolox equivalents per mg of dry extract and 0.45 μg ascorbic acid equivalents per mg of dry extract, respectively. Conclusion In addition to previously identified compounds in the acetone extract, atraric acid was identified for the first time by using HPLC method, and orcinol, β-orcinol, lauric alcohol, atranol, and rangiformic acid by using GC-MS method. The results of biological activity proved that acetone extract had antioxidant capacity and weak anticholinesterase activity. Reduction of the number of micronuclei in human lymphocytes, classified C. rangiformis as promising substances source with beneficial effects on DNA damage.