The antibacterial effect of the crude methanol extracts and purified fractions of Cladophora
glomerata (Linnaeus) Kützing (Cladophoraceae) against multidrug resistant human pathogen Acinetobacter
baumannii and fish pathogens were investigated. Cladophora glomerata demonstrated appreciable activity
against the human pathogen A. baumannii and fish pathogens Vibrio fischeri, V. vulnificus, V. anguillarum,
V. parahaemolyticus, E. coli and B. cereus. TLC Purified fractions III and V of green seaweed C. glomerata
inhibited the human pathogen A. baumannii and fish pathogens V. fischeri and V. vulnificus. Purified fraction
II of the same seaweed inhibited only V. fischeri and V. vulnificus. Methanol extract of C. glomerata inhibited
E. coli and B. cereus growth at a minimum inhibitory concentration of 75 µg/ml and other species at 100 µg/ml.
Whereas, V. vulnificus growth was inhibited at a minimum concentration of 125 µg/ml. GC-MS analysis revealed
the presence of hydrocarbon compounds in active fractions II, III and V of C. glomerata. These findings
demonstrate that the methanol extract and their purified fractions of C. glomerata exhibited appreciable
antimicrobial activity and thus have great potential as a source for natural health products.