Antibacterial activity of seaweed (Kappaphycus) extracts against infectious pathogens

Abstract

Natural products represent a potential source for the search of new drug. Among them, seaweeds can be highlighted because of its abundance in nature and richness in bioactive compounds. Screening of these for antimicrobial compounds is vital due to increasing demand of therapeutic drugs in treatment of pathogenic infection. In this study, the antibacterial activity of seaweeds (Kappaphycus alvarezii, Kappaphycus striatum Kappaphycus alvarezii (Doty) Doty ex P. C. Silva and Kappaphycus striatum (F.Schmitz) Doty ex P. C. Silva. was tested against human bacterial pathogens (Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, Staphylococcus aureus, Streptococcus pyogenes, Serratia sp. and Proteus sp.). Different seaweeds extracts (acetone, benzene, butanol, chloroform, ethanol, ethyl acetate, hexane, isoamyl alcohol, methanol, propanol and toluene) were evaluated for antibacterial activity by agar well diffusion methods. In the present study, the best results were obtained for chloroform and isoamyl alcohol extracts, which presented inhibition zones for the majority of the pathogens. The K. striatum species activity was high when compared with K. alvarezii. The chloroform and isoamyl alcohol extracts showed maximum activity and showed highest zone of inhibition of 22 and 20 mm, respectively. The results indicate significant capacity and future scope for the use of seaweed against a wide range of microbial populations. Key words: Seaweed, antibacterial activity, antimicrobial agent, Kappaphycusalvarezii, Kappaphycus striatum.