Cauchao Berry (Amomyrtus luma) as a Promising Source of Bioactive Compounds: Optimized Extraction, Phytochemical Characterization, and Assessment of Antioxidant and Antidiabetic Potential

The Cauchao berry (<i>Amomyrtus luma</i>), native to southern Chile and Argentina, has been traditionally used in folk medicine, yet scientific evidence supporting its bioactive potential remains limited. This study aimed to optimize the extraction of bioactive compounds and assess their antioxidant and antidiabetic properties. Fresh and freeze-dried samples were compared in terms of proximate composition, dietary fiber, reducing sugars, and fatty acid profiles. Proximate and fiber contents were determined using AOAC methods, while fatty acids were analyzed by gas chromatography, and α-tocopherol levels were measured via HPLC. Extraction optimization was conducted using a Box-Behnken design within a response surface methodology framework, employing freeze-dried samples. Total phenolic (TPC), flavonoid (TFC), and anthocyanin (TAC) contents were quantified spectrophotometrically. Antioxidant potential was assessed by DPPH and ORAC assays, while α-glucosidase inhibition determined antidiabetic activity. Phenolic profiles were characterized by HPLC. Optimal extraction conditions (58% ethanol, 60% ultrasound power, 30 min) enhanced antioxidant response. Results showed high fiber content (~39%), linoleic acid as the predominant fatty acid, and an α-tocopherol concentration of ~95 µg/g. TPC, TFC, and TAC values reached 25.43 ± 0.85, 46.51 ± 1.38, and 5.91 ± 0.40 mg/g d.m., respectively. Antioxidant capacity was 289.54 ± 9.05 μmol TE/g (DPPH) and 451.09 ± 6.04 μmol TE/g (ORAC). The IC₅₀ for α-glucosidase inhibition was 0.558 ± 0.015 mg/mL. Phenolic compounds were identified. These findings position the Cauchao berry as a promising source of bioactive compounds with potential health benefits.