Bioactivity of the red algae Asparagopsis taxiformis collected from the southwestern coast of India

Among the diverse variety of red algae, Asparagopsis taxiformis constitutes one of the abundant biomass in the Kollam coast (Southwest coast of India). Therefore, in the present study, A. taxiformis was collected, extracted and fractionated using column chromatography. The individual fractions were evaluated in vitro for their antifouling, anticyanobacterial, piscicidal and crustaceans toxicity assays. The fraction eluted with 2:8, petroleum ether and ethyl acetate exhibited strong and broad spectrum of bioactivity. In antifouling assay against Limnea truncatula, the active algal fraction produced 80% of foot repellency at 150 mg/L whereas in anticyanobacterial assay, the active fraction inhibited 100% growth of Trichodesmium sp. at 320 mg/L. The algal fraction showed higher piscicidal effect at the level of 60 mg/L. The crustacean toxicity of the active fraction was also evaluated to find compounds without toxicity in non target organisms, Penaeus monodon and Macrobrachium rosenbergii. It was found that column fraction showed less toxicity against the non target organisms. The chemical constituents of the active fraction were identified by means of chromatographic systems such as TLC, reverse phase HPLC and GC-MS. The overall activity profile envisages that the active column fraction of A. taxiformis might contain synergistic bioactive metabolites that could be utilized for the control of fouling organisms, algal bloom and herbivorous/predaceous fishes in aquaculture ponds.