A Passiflora incarnata extract exerts multi-target effects on selected sleep-related receptors.

ETHNOPHARMACOLOGICAL RELEVANCE: Since ancient times, passionflower (Passiflora incarnata L.) is used to treat insomnia, nervousness, anxiety, and other neurological conditions, but the understanding of the underlying neurophysiological processes is largely limited to the involvement of the GABAergic system.

AIM OF THE STUDY: This work aims to elucidate the mechanism by which P. incarnata modulates selected sleep-promoting receptors and neurotransmitter pathways in the central nervous system.

MATERIALS AND

METHODS

We studied the effects of a standardized P. incarnata extract on selected sleep-promoting receptors and neurotransmitters using competitive binding and uptake assays in vitro.

RESULTS

The P. incarnata extract inhibited the binding of [3H]-DPCPX to the adenosine A1, [125I]-ZM 241385 to the adenosine A2A, and [125I]-LSD to the serotonin 5-HT2A receptor, in a concentration-dependent manner, whereas the melatonin MT1-and orexin OX1-receptors were unaffected. The extract also inhibited [3H]-dopamine, [3H]-norepinephrine, and [3H]-serotonin uptake into rat cortical synaptosomes.

CONCLUSION

Hitherto undetermined active components of the P. incarnata extract inhibit monoamine uptake and show affinity to the adenosine A1 and A2A and the 5-HT2A serotonin receptor. The results of this exploratory study support the longstanding use of P. incarnata to promote sleep.