Comparative studies on anxiolytic activities and flavonoid compositions of Passiflora edulis 'edulis' and Passiflora edulis 'flavicarpa'

To compare the anxiolytic activities and flavonoid compositions of the two populations of the species Passiflora edulis, Passiflora edulis 'edulis' with purple fruit and Passiflora edulis 'flavicarpa' with yellow fruit.

Four samples for each population of Passiflora edulis were collected from different districts of China. Swiss albino mice were used as experimental animals in elevated plus-maze (EPM) test to assay the anxiolytic effects of ethanol extracts of the samples. The conventional parameters and ethological items of the behavior of the mice were recorded and analyzed. Flavonoid compositions of the samples were analyzed by RP-HPLC monitored with diode array detection and the chromatograms were compared.

The ethanol extracts of the samples of Passiflora edulis 'flavicarpa' displayed anxiolytic activity at 400 mg/kg, while those of Passiflora edulis 'edulis' exhibited sedative effect at 400 mg/kg. The chromatograms of the samples belonging to similar population of Passiflora edulis were identical, but those belonging to different population were distinct from each other. The series of peaks between 16 and 24 min in the chromatograms of Passiflora edulis 'flavicarpa' did not appear in those of Passiflora edulis 'edulis', either did the peaks between 54 and 90 min in chromatograms of Passiflora edulis 'edulis' not appear in those of Passiflora edulis 'flavicarpa'. The six major flavonoid compounds isolated from the leaves of Passiflora edulis 'flavicarpa', lucenin-2, vicenin-2, isoorientin, isovitexin, luteolin-6-C-chinovoside, and luteolin-6-C-fucoside, had not been detected in Passiflora edulis 'edulis'.

Passiflora edulis 'flavicarpa' is extremely different from Passiflora edulis 'edulis' and they should be distinguished when pharmacological studies are performed on them. The aerial part of Passiflora edulis 'flavicarpa' is possible to be utilized as the resource of Passionflower Extract.