Abstract

SCREENING OF ANTIMICROBIAL ACTIVITIES IN THE INK OF CEPHALOPODS AGAINST HUMAN PATHOGENS

Jemma Hermelin Jesy Diaz* and R. D. Thilaga

ABSTRACT

The present study has been carried out to find out the antimicrobial activities of the crude and partially purified ink extract of cephalopods Loligo duvauceli (squid) and Sepia pharaonis (cuttlefish). Antimicrobial activity of the ink was tested against eight bacterial strains and one fungal strain by well diffusion method. At 100μl concentration crude ink of L.duvauceli showed activity with the inhibition zone between 17 to 28mm and at 20μl concentration the extract showed a significant activity against Vibrio fischeri. No activity was recorded against other bacterial strains. The crude ink of S.pharaonis at 100μl concentration showed activity with the inhibition zone ranging from 6mm to 20mm. At 20μl concentration it showed activity only against Klebsiella pneumonia and Aeromonoas hydrophila. The crude ink of L.duvauceli and S.pharaonis was partially purified and fractionated by ammonium sulphate precipitation and the fractionated proteins were tested for antimicrobial activity. Of the six fractions (L.duvauceli) only two fractions (30% and 40%) of partially purified ink exhibited activity. Among the two, 30% fractionated ink exhibited significant activity against K.pnumoniae, A.hydrophila and E.coli. Antimicrobial activity of partially purified fractionated ink of S.pharaonis exhibited inhibitory zone varied from 14mm to15mm. Among the different fractions, 80% fractionated ink showed maximum activity against bacterial and fungal strains.

Keywords: Loligo duvauceli, Sepia pharaonis, antimicrobial activity, inhibition zone, partially purified ink.