Bioprospecting of lichens of the genus parmotrema A Massal parmeliaceae in Kerala

Abstract

Parmotrema A. Massal.(Parmeliaceae family) is the dominant lichen genera of Kerala part of the Western Ghats. The present study has made two additions to the lichen biota of Kerala: Parmotrema claavuliferum (Räsänen) Streimann and Parmotrema abnuens (Nyl.) Hale, rediscovered one untraceable species Parmotrema margaritatum (Hue) Hale and also reported the extensive occurrence of three species Parmotrema tsavoense (Krog &Swinscow) Krog &Swinscow and Parmotrema chinense (Osbeck) Hale & Ahti. The ecological and bio-geographic evaluations of the 29 species were conducted regarding alpha diversity and IVI value. The biogeography of these species was recorded using GIS, and distribution maps were prepared. The chemical prospecting of these lichens was carried out to identify the active principles and to find out the novel phytochemicals with pharmaceutical and industrial applications. The GC-MS analysis elucidated several active principles in this genus. Benzoic acid, Benzaldehydes and Ethyl 2,4- dihydroxy-6-methylbenzoate Orcinol and Squalene are compounds with anti-cancer, antibacterial, anti-fungal, anti-oxidant, Anti-diabetic, and Anti-inflammatory properties. Phthalic acid is reported to have insect-repellant and larvicidal properties. The total phenol and flavonoid content was determined, and P. clavuliferum is the species with high phenol and flavonoid content. The quantity of phenols and flavonoids has correlation with several medicinal properties. The anti-microbial properties of the genus Parmotrema were evaluated against various pathogenic bacteria and fungi, and their antimicrobial properties were evaluated. In summary, the rich lichen biodiversity of the genus Parmotrema of Kerala and the broad spectrum of chemical substances within this genus have immense biopharmaceutical potential and industrial applications. Hence, the conservation and sustainable utilization of these resources require immediate attention and action.