Antibacterial activity of Ginseng (Panax ginseng C. A. Meyer) stemsleaves extract produced by subcritical water extraction

Antibacterial activities of ginseng extracts produced from ginseng by-products, stems and leaves, using subcritical water extraction (SWE) at 110, 165 and 190 degrees C, were evaluated and compared with those of ginseng extracts prepared by hot water and ethanol extraction. The ginseng stemsleaves extract produced by SWE at 190 degrees C contained the greatest concentration of phenolics (98.4mgGAEg1 of extract). All ginseng extracts inhibited the growth of Bacillus cereus, Salmonella enteritidis, Escherichia coli O157:H7 and Listeria monocytogenes. Among four strains, B. cereus was more sensitive to the ginseng extract by SWE at 190 degrees C than other bacteria. Cell membranes of bacteria were disrupted by the addition of SWE ginseng extract, observed by transmission electron microscopy (TEM), with the release of cellular contents. These findings provided evidence about the potential utilisation of ginseng stems and leaves by using an environmental friendly extraction process, SWE, to produce ginseng extract for the inhibition of bacteria growth.