In-vitro Antimicrobial and Antioxidant activities of Himalayan Lichen Heterodermia obscurata (Nyl.) Trevis

The lichen Heterodermia obscurata is a foliose lichen, collected from the Munsiyari Hills of the Himalayan region.In the present study, we investigated the antimicrobial, and antioxidant activities of this macro lichen.The acetone, chloroform, ethyl acetate, and methanol extracts of lichen were subjected to antimicrobial activities at 5mg/ml (10µl/disc) concentration by disc diffusion assay.Methanol extract of H. obscurata showed more inhibition against A. baumannii with zone of inhibition (ZOI) 13.2±0.5mmthan other microorganisms.In contrast, the significant minimum inhibitory concentration (MIC) observed against K. pneumoniae was 120µg/ml.Methanol extracts showed more inhibition of F. oxysporum than A. niger.The ZOI of antimicrobial activities also summarised by Principal Component Analysis (PCA).The antioxidant activities of methanol extract are the most active than the other extracts at 1 mg/ml concentrations.The maximum free radicals scavenging activities was 68.45±0.6%calculated in methanol extract.The lichen thallus forms a potential candidate for drug discovery and development.Further studies on the isolation of active principles from the lichens and their bioactivities are under investigation.