ANTIBACTERIAL AND ANTIFUNGAL ACTIVITY OF THREE RAMALINA SPECIES

Abstract

Lichens are an association of a photobiont (an alga or a cyanobacterium) and a mycobiont (a fungus). The lichen genus Ramalina is one of the cosmopolitan lichen genera and is characterized by fruticose thallus. In the present study, an antibacterial and antifungal activity of an extract of three Ramalina species (Ramalinaceae) viz. R. hossei Vain, R. conduplicans Vain and R. pacifica Asahina obtained by maceration process were investigated. The lichens were collected from different places of Shivamogga district, Karnataka, India and identified on the basis of morphological, anatomical and chemical tests. The antibacterial and antifungal activity of lichen extracts was carried out by Agar well diffusion and Poisoned food technique respectively. Overall, B. cereus and E. coli were inhibited to higher extent and least extent respectively by extracts of Ramalina species. R. pacifica and R. hossei inhibited bacteria to highest and least extent respectively. In the case of antifungal activity, marked and least inhibitory activity was shown by an extract of R. hossei and R. pacifica respectively. Among fungi, Alternaria sp. and Fusarium sp. were inhibited to highest and least extent respectively. The observed antimicrobial potential could be ascribed to the presence of secondary metabolites such as usnic acid, salazinic acid and sekikaic acid present in the Ramalina species.