Cancer-chemopreventive actvity of secondary metabolites isolated from Xanthoparmelia conspersa lichen

Secondary metabolites are substances produced primarily by mycobionts and deposited on the lichen hyphae. They are derived from various metabolic pathways such as: mevalonic, shikimic and acetyl-polymalonyl acid pathways. Four metabolites and their parent drugs were isolated by using solvent extraction (Soxhlet extraction method) and repeated chromatographic methods (HPLC) and next determined by spectroscopic methods including nuclear magnetic resonance (NMR) and spectroscopy correlation of NMR. One new compound for Xanthoparmelia conspersa (Ehrh. ex Ach.) Hale was identified and confirmed one more time by our team, as atraric acid (2,4-dihydroxy-3,6-dimethylobenzoate) [1]. Furthermore, the activity using a battery of 13 luciferase cancer-related reporter gene assays for the parent drug and some of its metabolites showed that atraric acid and usnic acid exhibited a significant cancer-chemopreventive activity. However, little or weak anticancer activities were observed for stictic and norstictic acids. Our present study is important for further investigates of cancer-chemopreventive activity of the secondary metabolites isolated from lichens, their use in the traditional medicine and to understand their metabolic fate or deposition in human organism.

References:

[1] Łaska G, Kiercul S. Pharmacological activity of secondary metabolites isolated from Xanthoparmelia conspersa (Ehrh. ex Ach.) Hale lichen. Planta Med 2014; 10: 835