Antimicrobial properties from lichens: An evaluation of the antimicrobial properties of English churchyard lichens

The emergence of multidrug resistant bacteria has driven the need for novel antibiotics. Lichens naturally produce a wide range of unique defence chemicals and have already, historically shown medicinal efficacy. Antimicrobial properties of Lichens were investigated. Ten common churchyard species were sampled and extracted in acetone, namely Caloplaca flavescens, Diploicia canescens, Cladonia fimbriata, Psilolechia lucida, Lecanora campestris subsp. Campestris, Lecanora sulphurea, Pertusaria amara f.amara, Lepraria incana, Porpidia tuberculosa and Xanthoria calcicola. Extracts were impregnated into filter paper discs and tested against Gram positive and Gram negative bacteria and two fungi using the disc diffusion susceptibility test method. Extracts of Diploicia canescens, Psilolechia lucida, Lecanora sulphurea, Pertusaria amara f. amara and Lepraria incana showed inhibition against Gram positive bacteria. Diploicia canescens, Pertusaria amara and Lepraria incana also inhibited the dermatophyte fungi tested. Further studies should isolate their metabolites in order to find the agents responsible for the antimicrobial activity. These agents may or may not be novel to medicine but could be of current medicinal interest.