In Vitro Antimicrobial Potential of the Lichen Parmotrema sp. Extracts against Various Pathogens

Objective(s): The ongoing increasing antibiotic resistance is one of the biggest challenges faced by global public health. The perennial need for new antimicrobials against a background of increasing antibiotic resistance in pathogenic and opportunistic microorganisms obliges the scientific community to constantly develop new drugs and antimicrobial agents. Lichens are known prolific sources of natural antimicrobial drugs and biologically active natural products. This study was aimed to explore in vitro antimicrobial activity of lichen Parmotrema sp. Material and Methods: The methanol and aqueous extracts of lichen Parmotrema sp. was extracted using Soxhlet extractor. Antibiotic assessment of methanol and aqueous extracts was done against eight bacterial (Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Salmonella sp., Shigella sp., Enterococci faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae,) clinical pathogens and five plant pathogenic fungal strains (Aspergillus terreus strain JAS1, Scedosporium sp. JAS1, Ganoderma sp. JAS4, Candida tropicalis and Fusarium sp.) by Kirby-Bauer method. Results: The methanol lichen Parmotrema sp. extract inhibited all the test organisms. The highest antibacterial activity was found against Pseudomonas aeruginosa and Staphylococcus aureus. The weakest activity was manifested in Salmonella sp. and Scedosporium sp. JAS1. Strong antifungal effect was found against Ganoderma sp. JAS4 and Fusarium sp. The aqueous lichen Parmotrema sp. extract revealed neither antibacterial nor antifungal activity. Conclusion: The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens.