Comparative Evaluation of Maceration, Reflux, Ultrasound-Assisted Extraction and Microwave-Assisted Extraction on the Antioxidant Activity of Leea aequata L. Leaves via DPPH Assay

Abstract

Introduction: Natural antioxidants from medicinal plants have gained attention due to their ability to neutralize free radicals and reduce oxidative stress-related disorders. Leea aequata L. leaves are traditionally used in North Sumatra, Indonesia, and are reported to contain secondary metabolites with potential antioxidant activity. Aims: This study aimed to compare the antioxidant activity of Leea aequata L. leaf extracts obtained by maceration, reflux, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) using the DPPH radical-scavenging assay. Methods: Powdered dried leaves of Leea aequata L. were extracted using 96% ethanol through four extraction techniques. Basic physicochemical characterization was performed to ensure the quality of the dried plant material, while phytochemical screening was conducted to identify major secondary metabolites. Antioxidant activity was determined using the DPPH radical scavenging assay and expressed as IC₅₀ values. Results: The extraction methods produced different yields and antioxidant activities. MAE gave the highest extraction yield (29.5%), followed by maceration (26.0%), UAE (20.0%), and reflux (11.0%). Phytochemical screening revealed the presence of flavonoids, phenolics, tannins, saponins, alkaloids, and steroids/triterpenoids. All extracts demonstrated very strong antioxidant activity, with IC₅₀ values below 50 ppm. Among the tested extracts, MAE exhibited the strongest antioxidant activity, with the lowest IC₅₀ value of 12.586 ± 0.04 ppm, followed by UAE (29.786 ± 0.05 ppm), maceration (37.656 ± 0.06 ppm), and reflux (40.581 ± 0.07 ppm). Conclusion: MAE was the most effective method for obtaining L. aequata leaf extract with strong antioxidant activity, as indicated by the strongest DPPH radical-scavenging activity.