In vitro evaluation of antimicrobial activity of methanolic extract from selected species of Cephalopods on clinical isolates

Bioactive substances from marine biota have been found useful as special tools in pharmacological and biomedical research. In the present study, the in vitro antimicrobial activity of crude methanolic extracts of six species of cephalopods (Sepia kobiensis, Sepiella inermis, Sepioteuthis lessoniana, Octopus aegina, Octopus aerolatus, Octopus dollfusi) from Cuddalore (Southeast coast of India) was studied. The antimicrobial activity was screened against 10 species of clinically isolated human pathogenic bacteria namely Vibrio chlolerae, Pseudomonas aeruginosa, Klebsiella pnemoniae, Vibrio alginolyticus, Staphylococcus aureus, Vibrio parehaemolyticus, Streptococcus sp., Streptococcus pnemoniae, Salmonella sp. and Escherichia coli and five fungal strains such as Alternaria alternata, Candida tropicalis, Pencillium italicum, Fusarium equisetii and Candida albicans. Different concentrations such as 25, 50, 75 and 100% were prepared and tested against the microbial strains for their inhibitory activities, using the disc diffusion method. The minimum inhibitory concentration (MIC) of methanolic extract of cephalopods ranged from 60 to 100 mg/ml. The results were discussed in the light of positive and negative control apart from the concentrations tested.