Modulation of the γ-aminobutric acid (GABA) system by Passiflora incarnata L.

Kurt Appel (1) , Thorsten Rose (1) , Bernd Fiebich (1) , Thomas Kammler (2) , Christine Hoffmann (2) , Gabriele Weiss (2)

1 VivaCell Biotechnology GmbH
2 Medical Science

Passiflora incarnata L. (Passifloraceae) is important in herbal medicine for treating anxiety or nervousness, GAD, symptoms of opiate withdrawal, insomnia, neuralgia, convulsion, spasmodic asthma, ADHD, palpitations, cardiac rhythm abnormalities, hypertension, sexual dysfunction, and menopause. However, the mechanism of action is still under discussion. Despite gaps in our understanding of neurophysiological processes, it is increasingly being recognized that dysfunction of the GABA system is implicated in many neuropsychiatric conditions, including anxiety and depressive disorders Therefore, we investigated the in vitro effects of a dry extract of Passiflora incarnata (sole active ingredient in Pascoflair® 425mg) on the GABA system. The extract inhibited [³H]-GABA uptake into rat cortical synaptosomes but had no effect on GABA release and GABA transaminase activity. Passiflora incarnata inhibited concentration dependent the binding of [³H]- SR95531 to GABAA-receptors and of [3H]-CGP 54626 to GABAB-receptors. Using the [35S]-GTPS binding assay Passiflora could be classified as an antagonist of the GABAB receptor. In contrast, the ethanol- and the benzodiazepine-site of the GABAA-receptor were not affected by this extract. In conclusion, we show the first evidence that numerous pharmacological effects of Passiflora incarnata are mediated via modulation of the GABA system including affinity to GABAA and GABAB receptors, and effects on GABA uptake.

Mots clés: Life Sciences

Kurt Appel, Thorsten Rose, Bernd Fiebich, Thomas Kammler, Christine Hoffmann, et al.. Modulation of the γ-aminobutric acid (GABA) system by Passiflora incarnata L.. Phytotherapy Research, 2010, ⟨10.1002/ptr.3352⟩. ⟨hal-00599846⟩