LC-ESI-MS/MS profiling and antioxidant activity of okra (Abelmoschus esculentus (L.) Moench) fruit pericarp from different accessions cultivated in Biskra, South Algeria

Introduction: Okra (Abelmoschus esculentus (L.) Moench) is a widely consumed vegetable valued for its rich nutritional content and diverse bioactive compounds. Objective: The objective of this study was to evaluate the extraction yield, phenolic composition and antioxidant capacity of hydro-ethanolic extract of fresh fruit pericarp of late-maturity okra from six accessions grown in Biskra (South Algeria) where the pericarp is considered as an agricultural by-product. Methods: Total phenolic and flavonoids contents were analysed by Folin Ciocalteu and aluminum chloride assays, respectively. Antioxidant capacity was studied in vitro by using DPPH radical scavenging activity, ABTS and phenanthroline assays. Phenolic compounds were analysed by LC-ESI-MS/MS. Results: The hydroethanolic extract from the BA accession collected from Beni Abbes region had the highest extraction rate at 17.910.37%. The GH accession collected from Ghardaia region exhibited the highest values of total phenolic contents (38.772.6 g GA/mgDE). This accession showed the highest activity in the DPPH assay (IC50=372.992.84 μg/ml). The extracts from BI1 accession exhibited a higher capacity to scavenge the ABTS•+ radical (IC50=187.027.00 μg/ml). The extracts from the AD accessions collected from Adrar region demonstrated strong antioxidant capacity in reducing metallic ions (A0.5 values=159.7517.32 μg/ml). Ten distinct phenolic compounds were identified, with most of these compounds being reported for the first time. Notably, p-coumaric, caffeic, o-coumaric, and salicylic acids were found in the extracts of all accessions. Conclusion: Okra fruit pericarp at late-stage maturity is considered an important and diverse source of medically phenolic compounds.