title: Immunomodulatory and anti-SARS activities of Houttuynia cordata.
abstract: BACKGROUND
  Severe acute respiratory syndrome (SARS) is a life-threatening form of pneumonia caused by SARS coronavirus (SARS-CoV). From late 2002 to mid 2003, it infected more than 8000 people worldwide, of which a majority of cases were found in China. Owing to the absence of definitive therapeutic Western medicines, Houttuynia cordata Thunb. (Saururaceae)(HC) was shortlisted by Chinese scientists to tackle SARS problem as it is conventionally used to treat pneumonia.
  
  
  OBJECTIVE
  The present study aimed to explore the SARS-preventing mechanisms of HC in the immunological and anti-viral aspects.
  
  
  RESULTS
  Results showed that HC water extract could stimulate the proliferation of mouse splenic lymphocytes significantly and dose-dependently. By flow cytometry, it was revealed that HC increased the proportion of CD4(+) and CD8(+) T cells. Moreover, it caused a significant increase in the secretion of IL-2 and IL-10 by mouse splenic lymphocytes. In the anti-viral aspect, HC exhibited significant inhibitory effects on SARS-CoV 3C-like protease (3CL(pro)) and RNA-dependent RNA polymerase (RdRp). On the other hand, oral acute toxicity test demonstrated that HC was non-toxic to laboratory animals following oral administration at 16 g/kg.
  
  
  CONCLUSIONS
  The results of this study provided scientific data to support the efficient and safe use of HC to combat SARS.
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Kit-Man
authors.initials: KM
authors.lastname: Lau
authors.forename: Kin-Ming
authors.initials: KM
authors.lastname: Lee
authors.forename: Chi-Man
authors.initials: CM
authors.lastname: Koon
authors.forename: Crystal Sao-Fong
authors.initials: CS
authors.lastname: Cheung
authors.forename: Ching-Po
authors.initials: CP
authors.lastname: Lau
authors.forename: Hei-Ming
authors.initials: HM
authors.lastname: Ho
authors.forename: Mavis Yuk-Ha
authors.initials: MY
authors.lastname: Lee
authors.forename: Shannon Wing-Ngor
authors.initials: SW
authors.lastname: Au
authors.forename: Christopher Hon-Ki
authors.initials: CH
authors.lastname: Cheng
authors.forename: Clara Bik-San
authors.initials: CB
authors.lastname: Lau
authors.forename: Stephen Kwok-Wing
authors.initials: SK
authors.lastname: Tsui
authors.forename: David Chi-Cheong
authors.initials: DC
authors.lastname: Wan
authors.forename: Mary Miu-Yee
authors.initials: MM
authors.lastname: Waye
authors.forename: Kam-Bo
authors.initials: KB
authors.lastname: Wong
authors.forename: Chun-Kwok
authors.initials: CK
authors.lastname: Wong
authors.forename: Christopher Wai-Kei
authors.initials: CW
authors.lastname: Lam
authors.forename: Ping-Chung
authors.initials: PC
authors.lastname: Leung
authors.forename: Kwok-Pui
authors.initials: KP
authors.lastname: Fung
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage* / Q000302:isolation & purification / Q000633:toxicity; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002681:China; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000633:toxicity; D005260:Female; D005434:Flow Cytometry; D052859:Houttuynia; D051379:Mice; D008807:Mice, Inbred BALB C; D045473:Severe acute respiratory syndrome-related coronavirus / Q000187:drug effects*; D045169:Severe Acute Respiratory Syndrome / Q000188:drug therapy*; D013154:Spleen / Q000166:cytology; D023382:Toxicity Tests, Acute
chemical_list: D000998:Antiviral Agents; D004365:Drugs, Chinese Herbal; C442781:Houttuynia cordata extract