Phytochemical analysis of Corticolous macrolichens and their substrates: assessing habitat specificity in Madhyamaheshwar Valley, Garhwal Himalaya, Uttarakhand

This study investigates the phytochemical composition of five corticolous macrolichen species (Hypotrachyna nepalensis, Parmotrema tinctorum, Ramalina conduplicans, Dolichousnea longissima and Usnea orientalis) and their associated bark substrates (Berberis jaeschkeana, Betula utilis, Rhododendron arboreum, Rhododendron campanulatum and Sorbus foliolosa) in Madhyamaheshwar valley. Phytochemical analysis using various solvent extracts (chloroform, ethyl acetate, ethanol and methanol) revealed distinct chemical profiles for each species. Parmotrema tinctorum exhibited a wide range of compounds including flavonoids, glycosides, saponins, tannins, phenols and terpenoids while saponins were commonly present in ethanolic extracts of most lichens. No alkaloids or steroids were detected in any of the lichen samples and terpenoids were absent in Hypotrachyna nepalensis and Usnea orientalis. Bark extracts from Berberis jaeschkeana showed the highest chemical diversity including flavonoids, glycosides, saponins, tannins, phenols and terpenoids while other bark substrates contained glycosides and terpenoids but lacked saponins in some cases. The study confirms that Corticolous macrolichens do not derive nutrients from their bark substrates, relying instead on environmental photosynthesis for sustenance. These findings underscore the role of environmental and physiographic conditions in supporting lichen diversity, highlighting their habitat preference for attachment and stability rather than chemical nourishment.