Isolation of the MAO-inhibitor naringenin from Mentha aquatica L.
OBJECTIVE
To isolate the compound(s) responsible for the MAO-inhibitory activity.


METHODS
Six extracts of varying polarity of Mentha aquatica L. were tested in a photometric peroxidase linked MAO bioassay. The 70% ethanol extract had highest inhibitory activity. (S)-Naringenin was isolated from the extract by bioassay guided fractionation on VLC and preparative TLC. The structure of the compound was determined by (1)H, (13)C and (13)C-DEPT NMR and optical rotation.


RESULTS
The IC(50) values for MAO inhibition by naringenin were 342+/-33 microM for the rat liver mitochondrial fraction, 955+/-129 microM for MAO-A and 288+/-18 microM for MAO-B.


CONCLUSIONS
The content of naringenin in Mentha aquatica might explain its use in traditional medicine for depression-like conditions.
Olsen
Helle T
HT
Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen O, Denmark.
Stafford
Gary I
GI
van Staden
Johannes
J
Christensen
Søren B
SB
Jäger
Anna K
AK
D000818:Animals; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D044950:Flavanones / Q000302:isolation & purification* / Q000494:pharmacology*; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D027541:Mentha / Q000737:chemistry*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology; D008996:Monoamine Oxidase Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats
D044950:Flavanones; D008996:Monoamine Oxidase Inhibitors; D010936:Plant Extracts; C005273:naringenin