ISOLATION, IDENTIFICATION AND SCREENING FOR BIOACTIVE COMPOUNDS WITH ANTIMICROBIAL ACTIVITIES FROM SUB-AERIAL CYANOBACTERIA OF EASTERN REGION, ODISHA

Background and Objectives: Cyanobacteria are rich in various bioactive compounds. This study aims to screen the antimicrobial activity of sub-aerial Cyanobacteria isolated from sub-aerial habitats (Old monuments and building facades). Materials and Methods: Crude aqueous and organic extracts were screened for phytochemical constituents and tested for their antimicrobial efficacy against human pathogens. The crude extract that showed better antimicrobial activities were further fractionated by column chromatography and purified by TLC. The active bands were scraped out separately and concentrated in vacuo to isolate pure compounds. Each purified compounds dissolved in respective solvents, assayed for antimicrobial activities were further characterised through FTIR and LC-MS. Results: The results indicated the presence of many secondary metabolites. Of the isolated purified compounds, the compounds from three species, viz. Scytonema hyalinum, Tolypothrix rechingeri, and Fischerella species exhibited antimicrobial activities, whereas others showed antibacterial activity. The FTIR spectra revealed the peaks of carboxylic acid, alkaloids, and phenolic compounds. The chemical compounds were identified as 1,3-dihydroxycyclohexane [Lyngbya kuetzingiana], 4-(4-hydroxyphenyl) butanoic acid [Nostoc linckia], octahydro-1H-indole-2-carboxylic acid [Scytonema sp., S. pseudoguyanensis, S. pseudohofmani], ergost-5-en-3-ol [Scytonema hyalinum],7,11-dihydroxysolasodine [Scytonema ocellatum], 2, 4-Bis (2-methyl-2-propanyl)phenol-phosphorous acid [Tolypothrix rechingeri] and Pentaphenyl ferrocene carboxamide [Fischerella sp.] respectively. Conclusion: Though it is firsthand information regarding the isolation of sub-aerial Cyanobacteria, with a production of different bioactive chemical compounds, further investigation is required for use in pharmaceutical industries against costly harmful antibiotics and chemotherapeutics.