Identification of electrophysiologically-active compounds for the malaria mosquito, Anopheles gambiae, in human sweat extracts

Med Vet Entomol. 1996 Jul;10(3):269-76. doi: 10.1111/j.1365-2915.1996.tb00742.x.


Human sweat samples were chemically fractionated into acid and non-acid components. The most abundant volatile compounds present in the fractions were identified by linked gas chromatography mass spectrometry. The acid fractions were found to be composed of a range of twenty aliphatic and three aromatic carboxylic acids ranging, on average, from 0.02 to 20 micrograms per ml of sweat sampled. Non-acid fractions were found to contain: 6-methyl-5-hepten-2-one, 1-octen-3-ol, decanal, benzyl alcohol, dimethylsulphone, phenylethanol, phenol and 4-methylphenol, collectively amounting to 0.1 and 3 micrograms per ml of sweat. The major component of sweat was found to be L-lactic acid which constituted from 1 to 5 mg/ml. Using the intact antennae of the anthropophilic malaria vector mosquito Anopheles gambiae Giles, the peripheral olfactory activities of compounds identified in the sweat fractions were investigated by electroantennography (EAG). Short-chain saturated carboxylic acids, methanoic, ethanoic, propanoic, butanoic, pentanoic and hexanoic acids were found to elicit significantly larger EAG responses than longer chain saturated carboxylic acids from female An.gambiae. For a given dose the largest amplitude EAG response was elicited by methanoic acid. Pentanoic acid elicited larger EAG responses than either butanoic or hexanoic acids. Two non-acidic compounds, 1-octen-3-ol and 4-methylphenol, were found to elicit significant dose-dependent EAG responses from female An.gambiae. 1-Octen-3-ol elicited larger EAG responses than 4-methylphenol for a given dose, but both compounds elicited smaller EAG responses than the same dose of C1-C6 straight-chain aliphatic carboxylic acids. The possible behavioural significance of the EAG-active compounds identified in human sweat samples is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Anopheles / physiology*
  • Cresols
  • Dose-Response Relationship, Drug
  • Electrophysiology
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Lactic Acid
  • Octanols
  • Sweat / chemistry*


  • Cresols
  • Octanols
  • 4-cresol
  • Lactic Acid
  • 1-octen-3-ol