Biological and antibacterial activities of the natural herb Houttuynia cordata water extract against the intracellular bacterial pathogen salmonella within the RAW 264.7 macrophage.
Salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, from self-limiting enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Recently, the emergence of multidrug-resistant strains of Salmonella sp. has caused more serious problems in public health. The present study investigated the antibacterial effects of Houttuynia cordata water extract (HCWE) against murine salmonellosis. In RAW 264.7 cells, there was no detectable cytotoxic effect of HCWE at any concentration between 25 and 100 microg/ml after 8-h incubation. The antibacterial activity of HCWE was then examined in a Salmonella enterica serovar (Salmonella typhimurium), and was found to increase in a dose-dependent manner at concentrations from 25 to 100 microg/ml during 8-h incubation. HCWE also affected RAW 264.7 cells including morphologic change and bacterial uptake, but there was no significant difference in bacterial replication in RAW 264.7 cells. With HCWE alone, nitric oxide (NO) production by RAW 264.7 cells did not increase, but when RAW 264.7 cells were infected by S. typhimurium, with or without HCWE, NO production with HCWE was 2-fold higher than that without HCWE. Treatment with HCWE did not affect inducible NO synthase (iNOS) mRNA expression by RAW 264.7 cells, but when RAW 264.7 cells with HCWE were infected by S. typhimurium, iNOS mRNA expression was increased during 8-h incubation. Furthermore, HCWE showed virulence reduction effects in S. typhimurium-infected BALB/c mice. After a lethal dose of S. typhimurium, the mortality rate in the HCWE untreated group was 100% at 7 d, but the HCWE 25, 50, and 100 microg/ml groups survived until 11, 17, and 23 d, respectively. These data suggest that HCWE is stable and beneficial in the treatment of bacterial infection including intracellularly replicating pathogens and may solve antimicrobial misuse and overuse.
Kim
Gon Sup
GS
Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, Republic of Korea.
Kim
Dong Hyeok
DH
Lim
Jeong Ju
JJ
Lee
Jin Ju
JJ
Han
Dae Yong
DY
Lee
Whi Min
WM
Jung
Won Chul
WC
Min
Won Gi
WG
Won
Chung Gil
CG
Rhee
Man Hee
MH
Lee
Hu Jang
HJ
Kim
Suk
S
D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D052859:Houttuynia / Q000737:chemistry*; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D010587:Phagocytosis / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012481:Salmonella Infections, Animal / Q000188:drug therapy; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000472:pathogenicity; D014774:Virulence; D014867:Water
D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal; C442781:Houttuynia cordata extract; D014867:Water; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse