PRELIMINARY PHYTOCHEMICAL AND ANTIMICROBIAL STUDIES ON THE CRUDE EXTRACT OF RED ALGAE GRACILARIA EDULIS AGAINST CLINICAL ISOLATES

Rajakumar R.* and Allwin Prem Singh Y.

ABSTRACT

Phytochemicals are naturally present in the seaweeds and are biologically significant and plays an essential role in defending themselves against various pathogenic microbes by showing the antimicrobial activity by inhibition or killing mechanisms. In the present study revealed that the preliminary phytochemical, antibacterial and antifungal activities of crude extract of Gracilaria edulis were investigated. The methanol and aqueous extracts of Gracilaria edulis showed the presence of a number of metabolites such as alkaloids, saponin, phenols, terpenoids, proteins, flavonoids, glycosides, coumarins and tannins. G.edulis showed the significant antibacterial activity against in the clinical pathogens of Pseudomonas aeroginosa, Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Streptococcus pyogenes, Salmonell typhi as well as the fungus Aspergillus niger, Aspergillus flavus, Rhizopus indicus and Candida albicans. The methanol extracts of G.edulis showed maximum activity of 18mm (100μg/ml) of inhibition zone against Staphylococcus aureus and followed by the methanolic extracts of P.aerogenosa (16mm) and aqueous extract of S.aureus (14mm) when it was compared to the positive control Gentamycin. The methanol extract showed the broader spectrum of antibacterial and antifungal activity when compared with aqueous extract.

Keywords: Antimicrobial, phytochemical, Gracilaria edulis, aqueous extract.