Kynurenic acid in honey from arboreal plants: MS and NMR evidence.
KYNA, a Trp metabolite, shows neuroprotective activity against excitotoxic amino acids by antagonizing the NMDA receptor (glycine, glutamate). Here we report the identification of KYNA by a combination of ESI-MS/MS and 1D- and 2D-NMR analyses in honey varieties of arboreal origin. KYNA are absent in single-flower honeys from herbal flowers. These different distribution patterns might possibly involve an indirect plant defence mechanism against fungal pathogens and herbivorous parasites, ever-present on wild trees. The presence of KYNA in honey may explain its pain-relieving effects reported in the literature. The substance, acting in concert with honey flavonoids (COX-2 inhibitors), by antagonizing the NMDA receptor may contribute to the antinociceptive effect of honey. Moreover, kynureninates, owing to their antimicrobial properties, can favour the successful outcome of wounds and burns.
Beretta
Giangiacomo
G
Istituto di Chimica Farmaceutica e Tossicologica Pietro Pratesi, Faculty of Pharmacy, University of Milan, Milan, Italy. giangiacomo.beretta@unimi.it
Caneva
Enrico
E
Facino
Roberto Maffei
RM
D006722:Honey; D006801:Humans; D007736:Kynurenic Acid / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008517:Phytotherapy
D007736:Kynurenic Acid