Dye yielding potential and antibacterial properties of lichens from Kerala, India

Abstract

Lichens are a group of lower plants that adapt to extreme environmental conditions. The utility of lichens is due to the wide range of secondary metabolites produced by them. The present study is to analyse the dye yielding potential and anti-bacterial properties of lichen species Heterodermia boryi, Hypotrachyna cirrhata, and Cladonia fruticulosa collected from different parts of Kerala. Dyes were extracted using methods such as Ammonia fermentation method (AFM), Di-methyl sulphoxide extraction method (DEM) and the boiling water method (BWM). The dye extracts were experimented on mulberry silk and banana fibre. The fibre stability was tested by exposure to sunlight and action with detergent and shampoo. Most of the dyed colours appeared to be stable. The colours were detected using COSMIN software. The colours that appeared were mainly shades of brown, khaki, tan and gold. AFM and DEM are better extraction methods than BWM. To investigate the antibacterial activity, methanol, ethanol, acetone, chloroform and distilled water extracts of lichens were tested against Gram-positive and negative bacteria along with positive control. Chloroform and acetone extracts showed exceptional inhibition activity followed by methanol and ethanol and the least activity by distilled water extracts. Extracts of H. cirrhata and C. fruticulosa showed better antibacterial activity than H. boryi. These results indicate the presence of different secondary metabolites.