Biological Activities Of Extracts From Green Marine Macroalgae, Halimeda Discoidea
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Date
2011
Authors
Supardy, Nor Afifah
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Macroalgae Halimeda discoidea was studied for its bioactivities and characterization of the bioactive fraction was carried out. The antimicrobial activity of 8 extracts with different polarities (methanol, ethyl acetate, diethyl ether, butanol, hexane and chloroform) was started with the screening against 18 bacteria, three yeast and five fungi, through the disc diffusion method. The result revealed that hexane extract was the most active extract, followed by the ethyl acetate (Soxhlet) and chloroform extracts. Hexane extract was active against five Gram-positive and three Gram-negative bacteria and two yeasts. Then, broth macrodilutan assay was carried out to determine the minimum inhibitory concentration (MIC) of all susceptible microbes. The results showed that the MIC values were in the range of 0.25 mg/ml to 1.00 mg/ml. Only four out of 13 susceptible microbes exhibited the minimum bactericidal concentration (MBC) of 1.00 mg/ml. The growth profile of Klebsiella pneumoniae ATCC 13883, MRSA and Candida albicans were determined for 48 hours at the concentrations of half MIC, MIC and double MIC. As the results, K. pneumoniae ATCC 13883, MRSA and C. albicans at double MIC showed reductions of approximately 1.9 log, 2.3 log and 3.0 log at 48 hours relative to the control, respectively. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to view the morphological changes of the K. pneumoniae ATCC 13883 and C. albicans cells treated with the hexane and chloroform extracts, respectively. At the concentrations of MIC and 100.00 mg/ml, morphological modifications such as shrinkage, lysing and breakage were observed in the treated cells.
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Keywords
Biological activities of extracts from , green marine macroalgae