Comparative study of secondary metabolites and bioactive properties of the lichen Cladonia foliacea with and without the lichenicolous fungus Heterocephalacria bachmannii

The phenolic, flavonoid, tannin and proanthocyanidin content of the lichen Cladonia foliacea with and without its lichenicolous fungus Heterocephalacria (Syzygospora) bachmannii was investigated. The phenolic compounds were quantified in organic extracts using ultrasonic extraction (acetone and methanol) and in milled material (the ground material diluted with microcrystalline cellulose). The total phenolic content depended on the solvent polarity, the extraction technique and the species. The results demonstrated that the highest total phenolic content was recorded in untreated milled material (935.75 μg GAE/g DW) of H. bachmannii plus C. foliacea, followed by C. foliacea (668.29 μg GAE/g DW). The antioxidant activities were evaluated by the in vitro scavenging capacity, iron reducing power, and iron chelating power. The results showed that the highest scavenging capacity were obtained in methanol extracts of C. foliacea with IC50 = 0.015 mg/mL, followed by methanolic extract of H. bachmannii plus C. foliacea that had a scavenging capacity and iron reducing power of (IC50 = 0.030 mg/mL and IC50 = 0.054 mg/mL, respectively). The milled material showed the highest iron chelating power (IC50 = 0.279 mg/mL). We conclude that Cladonia foliacea when parasitized by H. bachmannii possesses a high antioxidant potential in the methanolic extract. Acetone and methanol extracts, showed that extracts from lichen plus lichenicolous fungus contained different and possibly more effective bioactive molecules than the lichen alone. These included phenolic acids, alkanes and aromatic compounds. This is the first study to investigate the phenolic content and antioxidant capacity of a lichenicolous fungus, albeit based on differences between the lichen with and without the mycoparasite H. bachmannii .