Background: Lichens in symbiosis produce a wide range of primary and secondary fne compounds in extreme
environmental conditions that have a broad range of biological properties as well as antioxidant potential and can be
used in future pharmaceuticals as a natural source of antioxidant molecules.
Results: The two microlichen species collected are identifed based on morphological and molecular techniques; further studies are carried out by analyzing phytochemicals (FTIR, GC MS), and antioxidant assays are evaluated. The nonenzymatic antioxidant activity is evaluated by DPPH and FRAP assays. The methanol extract of both lichens showed
virtuous DPPH scavenge with IC50 of P. nitida (125.76±0.023 µg/ml) and G. scripta IC50 (176.90±0.058 µg/ml). FRAP
activity was prominent in the methalonic extract. The enzymatic antioxidant activity is observed by SOD and catalase
activity. The cytosolic (Cu–Zn-SOD and Fe-SOD) and mitochondrial SOD (Mn-SOD) are detected in lichens, though P.
nitida shows mitochondrial Mn-SOD and cytosolic Cu–Zn-SOD and Fe-SOD, whereas G. scripta has a single cytosolic
Cu–Zn-SOD; however, two isoforms of catalase were reported. GC–MS analysis screened bioactive metabolites such
as phenols, Quinons, heterocyclic compounds, benzofurans, fatty acids, pyrans, carboxylic acid, aliphatic aldehydes,
organic alcohol, fuorinated aliphatic substances, ketones, terpenes and fatty alcohols in P. nitida, whereas, in G. scripta
screened fatty acids, alcohols, hydrocarbons, carbonyl compounds, polyols, terpenes, glycosides, phenols, and sugar
alcohols detected in the chromatogram peak. FTIR analysis revealed functional groups like Alcohols, Amines, Amides,
Alkanes, Aldehydes, Carboxylic acid, Alkynes, Esters, Ketones, Anhydrides, Acid chlorides, Alkenes, Aromatic compounds, Nitro compounds, Alkyl and Aryl Halides in both lichens.
Conclusions: The results obtained in the present study proved that P. nitida and G. scripta have promising antioxidant
activity owing to the presence of polyphenols and terpenes, as evidenced by DPPH and FRAP assay along with enzymatic analysis (SOD and CAT). Thus both the lichens may be used as natural sources of new bioactive molecules
having pharmaceutical interest.
Keywords: 28s rRNA, Antioxidant, FTIR, GC–MS, Lichen, Phytochemicals, SEM.