# Efficient Extraction of Phenolic Compounds From Cariniana rubra Gardener Ex Miers From the Legal Amazon: Ultrasound‐Assisted Optimization, Chemical Characterization, and Antioxidant Potential

## TL;DR

This study explores efficient methods to extract antioxidant-rich phenolic compounds from Cariniana rubra, a plant native to Brazil, using ultrasound-assisted and traditional extraction techniques.

## Contribution

The study introduces optimized ultrasound-assisted extraction conditions for maximizing phenolic and flavonoid yields from Cariniana rubra.

## Key findings

- Ultrasound-assisted extraction (UAE) achieved a 49.60% yield with 50% ethanol in 132 minutes.
- Extracts showed strong antioxidant activity, with DPPH• IC50 values lower than Trolox.
- LC–DAD identified epicatechin, rutin, and myricetin as key phenolic compounds in the extracts.

## Abstract

Cariniana rubra, native to the Brazilian Cerrado and the Amazon‐Cerrado ecotone, is traditionally used in folk medicine but remains underexplored. This study optimized extraction yield and bioactive compound content using ultrasound‐assisted extraction (UAE) and Soxhlet extraction. A central composite rotational design (CCRD) assessed ethanol concentration and extraction time, with response surface modeling (RSM) determining optimal conditions. UAE yielded 49.60% (50% ethanol, 132 min) and Soxhlet 25.25% (78% ethanol, 300 min). Maximum phenolic compound contents were 382.62 mg GAE g−1 (UAE; 48 min) and 385.95 mg GAE g−1 (Soxhlet; 480 min). Flavonoid contents were 137.83 mg QE g−1 (UAE; 90 min) and 73.66 mg QE g−1 (Soxhlet; 120 min). Antioxidant activity was confirmed by DPPH•, with IC50 values of 37.73 µg mL−1 (UAE) and 36.20 µg mL−1 (Soxhlet), surpassing Trolox (23.64 µg mL−1), and equivalent to Trolox in ABTS assays (53.67 and 38.67 µM Trolox g−1) and FRAP (453.44 and 558.44 µM Fe2+ g−1). FT‐IR analysis confirmed phenolic compound indicators, while LC–DAD identified epicatechin, rutin, and myricetin. These optimized methods produced extracts with high antioxidant activity, suggesting potential for further applications.