Passiflora (passion fruit), which is widely employed in folk medicine as well as in the pharmaceutical industry, shows benefits for anxiety, nervousness, constipation, dyspepsia, and insomnia. This may stem from the fact that it is sometimes used to make a tea used as a sedative.
Yet the herbal pharmacopeia is highly heterogeneous. Passiflora genus, Passifloraceae, includes about 520 species. It's even not clear if the supposed benefits come from the plant or from endophytes (fungi or bacterium).
It is known that amphiphilic stilbene derivatives attenuate the neurotoxicity of soluble Aβ42 oligomers by controlling their interactions with cell membranes. Stilbene derivatives include resveratrol. Endophytic fungi isolated from various types of grapevines and Polygonum cuspidatum, the primary plant sources of resveratrol, demonstrated intriguing resveratrol-producing ability.
Only a handful of studies have been made on Passiflora edulis and Alzheimer's disease. Scientists from Vietnam and Algeria evaluated for neuroprotective activity in murine Alzheimer's disease model induced by aluminum chloride and D-galactose.
While those are not common animal models of Alzheimer's disease, they have a good reputation as good models of this disease to the point that some scientists still suggest that the dismissed relation between aluminum and Alzheimer's disease may have some substance after all.
The scientists analyzed the phytochemical properties of the polyphenolic stilbene-rich acetone fraction and showed that it contained different stilbenes including trans-piceatannol, scirpusins A-B and cassigarol E. Piceatannol is a metabolite of resveratrol.
The total phenolic content (TPC) of Passiflora edulis was 413.87 mg eqv/g which is much less than green tea.
When the Alzheimer's mice were treated at 100 mg/kg and 200 mg/kg, they spent less than 47% and 66% of the time in a Morris maze, respectively, than non-treated Azheimer's model mice.
Two simple stilbenes, trans-piceatannol and trans-resveratrol, showed selectively inhibitory activity in silico against AChE.
Two stilbene dimers, cassigarol E and scirpusin A, exhibited low inhibitory potential against AChE and BChE, significantly lower than those of the positive control, donepezil, and tacrine.
These findings suggest that the stilbenes from P. edulis seeds, particularly the stilbene dimers, warrant further investigation as potential neuroprotective candidates in the prevention of cognitive deficits associated with Alzheimer's disease.