Flavonoid profiling and antioxidant activity of Passiflora setacea DC. leaves

Abstract

The wild species Passiflora setacea DC., known as ‘maracujá-do-sono’ or ‘maracujá-sururuca’, has chemical and pharmacological properties that are important to the food and pharmaceutical industries. This study aimed to identify and quantify polyphenols and flavonoids in extracts from leaves of in vivo orchard-grown and greenhouse-derived P. setacea plants. The extracts were also evaluated for their antioxidant (AAO) and acetylcholinesterase (AChE) inhibitory activity. The polyphenols and flavonoids were quantified spectrophotometrically. Based on the results, the hydroalcoholic extract from the leaves of P. setacea (PSHF-01) plants grown in the orchard was selected for further studies. In this extract, the flavonoids were characterized and identified using spectrophotometric and chromatographic methods. In addition, its antioxidant potential was evaluated through DPPH free radical scavenging, the ß-carotene/linoleic acid lipid peroxidation method, and the liposome peroxidation assay (TBARS). Furthermore, in silico activity prediction for flavonoids from P. setacea was performed using the Active-IT system. The total polyphenol content of the extracts varied from 11.32 ± 0.33 to 40.59 ± 1.5 mg of gallic acid equivalents per gram of extract. For flavonoid quantification, the amounts ranged from 3.79 ± 1.10 to 33.65 ± 4.73 mg of total flavonoids per gram of extract, calculated as apigenin. The extracts were considered promising for antioxidant activity using the β-carotene/linoleic acid peroxidation method. Concerning AChE inhibition, the extracts did not show significant values (%I > 40%). In the selected extract, PSHF-01, isovitexin and isoorientin were identified by chromatographic techniques (TLC, HPLC-UV and UPLC-PDA-ESI-MS/MS). Furthermore, the compounds luteolin-( O -glucopyranosyl)- C -glucopyranoside, (iso)orientin-C-xyloside, vicenin II, (iso)vitexin-2”-O-xyloside, and (iso)orientin-C-rhamnoside were tentatively characterized by UPLC-PDA-ESI-MS/MS. HPLC-DAD method was developed and validated for the determination of isovitexin in PSHF-01. Antioxidant activity was detected only in the ß-carotene/linoleic acid assay, whereas no activity was observed in the DPPH or TBARS assays. These differences may be attributed to distinct mechanisms underlying each assay. In silico predictions indicated that the evaluated flavonoids have the potential to exhibit hepatic metabolic stability and antiparasitic, anti-inflammatory, antitumor, and immunomodulatory activities. These results enhance our understanding of the chemical composition and biological properties of P. setacea and open new avenues for future research that could support its pharmaceutical potential and agronomic applications.