Extraction of bioactive compounds from pine nut seed coat (Araucaria angustifolia (Bertol.) Kuntze) using emerging technologies.

Abstract

The valorization of agro-industrial residues requires efficient and sustainable extraction strategies to recover high-value bioactive compounds. However, the potential of Brazilian pine (Araucaria angustifolia (Bertol.) Kuntze) as a source of functional compounds remains poorly explored, particularly regarding the influence of different emerging extraction technologies on phenolic recovery and biological activity. This study presents a comprehensive comparison between ultrasound-assisted and high-pressure extraction strategies for recovering phenolic compounds from A. angustifolia seed coat, integrating chemical characterization, biological evaluation, and molecular docking approaches to identify the most efficient extraction strategy and elucidate the mechanisms underlying the observed bioactivities. Among the evaluated conditions, ultrasound-assisted extraction using an ethanol: water (80:20, v v-1) solvent system showed the best performance, yielding the highest total phenolic content (12.04 mg GAE g-1) and antioxidant activity (DPPH: 74.60 μmol TE g-1; ORAC: 148.50 μmol TE g-1). UHPLC-MS/MS analysis revealed quercetin as the predominant phenolic compound in the extract obtained under the best-performing extraction condition. Furthermore, this extract inhibited α-amylase by 34.3% at 0.50 mg mL-1 and pancreatic lipase by 89.07% at 0.5 μg mL-1. Molecular docking simulations demonstrated favorable interactions between gallic acid and the active sites of both enzymes, providing insights into the molecular basis of the observed inhibitory effects. Overall, these findings demonstrate that ultrasound-assisted extraction is an efficient green strategy for recovering bioactive compounds from A. angustifolia seed coat and highlight this underutilized agro-industrial residue as a promising source of sustainable functional ingredients for food and nutraceutical applications.