Multivariate Chemoprospecting of Five Ethnobotanically Important Himalayan Lichens Identifies <i>Parmotrema austrosinense</i> as a Promising Source of Phenolic Antioxidants

Lichens are an underexplored reservoir of nutritionally and pharmacologically relevant metabolites. This study provides one of the first comprehensive multivariate profiles of five ethnobotanically important lichen species (Lobaria retigera, Dirinaria consimilis, Parmotrema austrosinense, Ramalina conduplicans, and Usnea orientalis) from Uttarakhand, India, using an integrated screening approach to evaluate and rank their bioactive potential. A combined analysis of nutritional components (protein, carbohydrates, and essential minerals), phytochemicals (total phenolic and flavonoid content), preliminary antioxidant screening (2,2-diphenyl-1-picrylhydrazyl radical scavenging assay), and metabolite profiling (gas chromatography-mass spectrometry) was performed. Our results ranked and objectively identified P. austrosinense as the most promising lead species, exhibiting the highest total phenolic content (14.08 ± 2.53 mg gallic acid equivalents/g), flavonoid content (1.80 ± 0.23 mg catechin equivalents/g), protein content (24.36 ± 1.30 mg/g), and the most effective DPPH radical scavenging activity (83.05% inhibition). Although based solely on in vitro DPPH data, this screening establishes a prioritized ranking for further validation. Principal Component Analysis confirmed that these antioxidant traits were strongly intercorrelated. This integrated metabolomic screening approach establishes a robust chemotaxonomic and nutritional ranking, highlighting P. austrosinense as a prime candidate for subsequent in-depth investigations.