title: Plant monoterpenes do not raise plasma high-density-lipoprotein concentrations in humans.
abstract: BACKGROUND
  Low plasma concentrations of HDLs are associated with an increased risk of coronary artery disease. Two uncontrolled studies suggested that plant monoterpenes may have substantial HDL-cholesterol-elevating activity in humans. Each study used a proprietary mixture of 6 monoterpenes in olive oil.
  
  
  OBJECTIVE
  The present study was undertaken to test more rigorously the hypothesis that monoterpenes raise HDL concentrations in men with hypoalphalipoproteinemia.
  
  
  METHODS
  A double-blind, placebo-controlled crossover design was used. Twenty-four men aged 58-68 y (x: 62.3 y) with plasma HDL cholesterol <1.1 mmol/L, plasma triacylglycerols <3.5 mmol/L, and plasma total cholesterol <5.5 mmol/L at recruitment were randomly assigned to 6 capsules daily of a proprietary mixture of 6 monoterpenes in olive oil or 6 capsules daily of olive oil alone for 24 wk, followed by a washout period of 8 wk, and then the alternative capsules for 24 wk.
  
  
  RESULTS
  Five men dropped out. In the others, compliance was excellent as judged by capsule counts and urinary menthol glucuronide concentrations. No significant effects were observed on plasma HDL-cholesterol or apolipoprotein A-I concentrations, nor on plasma triacylglycerol, LDL-cholesterol, or apolipoprotein B concentrations.
  
  
  CONCLUSIONS
  Plant monoterpenes have no HDL-elevating activity of potential value for coronary artery disease prevention.
authors.affiliation: Department of Cardiovascular Biochemistry, St Bartholomew's and the Royal London School of Medicine and Dentistry, United Kingdom. n.e.miller@mds.qmw.ac.uk
authors.forename: C J
authors.initials: CJ
authors.lastname: Cooke
authors.forename: M N
authors.initials: MN
authors.lastname: Nanjee
authors.forename: P
authors.initials: P
authors.lastname: Dewey
authors.forename: J A
authors.initials: JA
authors.lastname: Cooper
authors.forename: G J
authors.initials: GJ
authors.lastname: Miller
authors.forename: N E
authors.initials: NE
authors.lastname: Miller
mesh_terms: D000368:Aged; D001054:Apolipoproteins A / Q000097:blood* / Q000187:drug effects; D001055:Apolipoproteins B / Q000097:blood; D002756:Cholagogues and Choleretics / Q000008:administration & dosage / Q000494:pharmacology*; D008076:Cholesterol, HDL / Q000097:blood* / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004338:Drug Combinations; D006801:Humans; D008297:Male; D008875:Middle Aged; D039821:Monoterpenes; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D013729:Terpenes / Q000008:administration & dosage / Q000494:pharmacology*; D014280:Triglycerides / Q000097:blood
chemical_list: D001054:Apolipoproteins A; D001055:Apolipoproteins B; D002756:Cholagogues and Choleretics; D008076:Cholesterol, HDL; D004338:Drug Combinations; D039821:Monoterpenes; D010936:Plant Extracts; D013729:Terpenes; D014280:Triglycerides; C018655:Rowachol