title: Piper sarmentosum increases nitric oxide production in oxidative stress: a study on human umbilical vein endothelial cells.
abstract: OBJECTIVE
  Nitric oxide produced by endothelial nitric oxide synthase (eNOS) possesses multiple anti-atherosclerotic properties. Hence, enhanced expression of eNOS and increased Nitric oxide levels may protect against the development of atherosclerosis. Piper sarmentosum is a tropical plant with antioxidant and anti-inflammatory activities. This study aimed to investigate the effects of Piper sarmentosum on the eNOS and Nitric oxide pathway in cultured human umbilical vein endothelial cells (HUVECs).
  
  
  METHODS
  HUVECS WERE DIVIDED INTO FOUR GROUPS: control, treatment with 180 microM hydrogen peroxide (H(2)O(2)), treatment with 150 microg/mL aqueous extract of Piper sarmentosum, and concomitant treatment with aqueous extract of PS and H(2)O(2) for 24 hours. Subsequently, HUVECs were harvested and eNOS mRNA expression was determined using qPCR. The eNOS protein level was measured using ELISA, and the eNOS activity and Nitric oxide level were determined by the Griess reaction.
  
  
  RESULTS
  Human umbilical vein endothelial cells treated with aqueous extract of Piper sarmentosum showed a marked induction of Nitric oxide. Treatment with PS also resulted in increased eNOS mRNA expression, eNOS protein level and eNOS activity in HUVECs.
  
  
  CONCLUSIONS
  Aqueous extract of Piper sarmentosum may improve endothelial function by promoting NO production in HUVECs.
authors.affiliation: Department of Physiology, Universiti Kebangsaan, Malaysia Medical Center, Kuala Lumpur, Malaysia.
authors.forename: Azizah
authors.initials: A
authors.lastname: Ugusman
authors.forename: Zaiton
authors.initials: Z
authors.lastname: Zakaria
authors.forename: Chua Kien
authors.initials: CK
authors.lastname: Hui
authors.forename: Nor Anita Megat Mohd
authors.initials: NA
authors.lastname: Nordin
mesh_terms: D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D031701:Piper / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013997:Time Factors; D014471:Umbilical Veins / Q000201:enzymology
chemical_list: D010936:Plant Extracts; D012333:RNA, Messenger; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III