Antibacterial Activities and Identification of Different Solvent Extracts of Kelp Powder

Kelp powder was extracted with 4 different solvents, including distilled water, methanol, n-butanol and ethyl acetate, and orthogonal test design was adopted to optimize the extraction technology, respectively. The primary structures and antibacterial activities of obtained 4 extracts were analyzed by HPLC and filter paper disc diffusion method, respectively. Glucose was identified in he water extract and the ethyl acetate extract, in which fructose was also identified, trehalose was identified in the methanol extract and the n-butanol extract, in which sucrose was also identified by RP-HPLC analysis. All the extracts showed significant higher inhibitory activity against Bacillus subtilis, Escherichia coli, Gaffkya tetragena and Staphylo- coccus aureus, and their inhibitory effects could be observed markedly at high dilution. Among the four solvent extracts, the ethyl acetate extract presented the strongest sensitivity to Bacillus subtilis.