Involvement of Isoorientin in the Antidepressant Bioactivity of a Flavonoid-Rich Extract from Passiflora edulis f. flavicarpa Leaves

Antioxidant compounds are increasingly attracting more attention by neuropharmacology studies due to the property of preventing brain damage. This study aimed to evaluate the supposed enhancement of antidepressant potentiality of a flavonoid-rich extract and investigate the new bioactive compounds from Passiflora edulis f. flavicarpa leaves. Quantitative analysis by RP-UHPLC-UV-DAD and extract yields were utilized in an experimental design to optimize flavonoid extraction. The total flavonoid content (11.42 mg/g), isoorientin (luteolin-6-C-β-D-glucoside) (5.21 mg/g), and LC-ESI-IT-MS/MS profile of the rich extract were determined and the flavonoid isoorientin (49 mg) was purified by preparative HPLC-UV-DAD. The antidepressant-like effects of the extract (50–100 mg/kg, p.o.) and isoorientin (1–10 mg/kg, p.o.) were investigated in the male mouse forced swimming test, in which both the positive control and experimental groups displayed reduced immobility time. Thus, the chemical results linked to the bioactivity assessments provide a 10-fold increase in the extract’s antidepressant potency and determine the relationship with the isoorientin flavonoid.