Evaluation of Different Extraction Methods on the Phenolic Profile and the Antioxidant Potential of Ceratonia siliqua L. Pods Extracts

The present work was designed to investigate the effects of different extraction processes, namely ultrasonic-assisted, supercritical fluid, microwave-assisted and Soxhlet applied to carob pods. The total phenolic quantification and the antioxidant activity were assessed by the means of rapid in vitro spectrophotometric assays; the phenolic profile was identified using ultra-high performance liquid chromatography coupled to mass spectrometry. The results revealed that the phenolic compounds and the antioxidant capacity varied significantly with the nature of the extraction process. The content of total phenolic compounds ranged from 11.55 to 34.38 mg GAE/g DW; the content of total flavonoids varied from 3.50 to 10.53 mg QE/g DW, and the content of condensed tannins fluctuated from 3.30 to 6.55 mg CE/ g DW. All extracts performed differently on antioxidant activity when determined by the DPPH assay producing a dose-dependent response, with IC50 extended from 11.33 to 6.07 mu g/mL. HPLC analysis enabled the identification of nine compounds. As a function of the studied extraction methods, the phenolic compound contents were positively correlated with antioxidant activity.

Automated summary

This study investigated the effects of different extraction processes on carob pods and found that the nature of the extraction process significantly influenced the phenolic compounds and antioxidant capacity. The content of total phenolic compounds, total flavonoids, and condensed tannins varied with different extraction methods. The extracts also exhibited different antioxidant activity, with IC50 values ranging from 11.33 to 6.07 μg/mL. HPLC analysis identified nine compounds and showed a positive correlation between phenolic compound contents and antioxidant activity.