DOI: 10.1177/1934578x261465251 ISSN: 1934-578X

Microwave-Ultrasound Assisted Extraction and Characterization of Phenolic Compounds From Heliotropium foertherianum : Optimization, Isolation, and Biological Activity Evaluation

Pham Kien Cuong, Vu Van Dung, Vu Ngoc Doan, Doan Tuan Dat, Nguyen Thi Kim Giang, Vu Quang Hung, Nguyen Thi Huong
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Objective

This study aimed to optimize microwave-ultrasound-assisted extraction (MUAE) for the recovery of phenolic acids from Heliotropium foertherianum leaves collected on the Truong Sa Islands, Vietnam, with a particular focus on rosmarinic acid (RA), caffeic acid (CA), and ferulic acid (FA), and to investigate the biological relevance of the obtained fractions and isolated compounds.

Methods

Extraction parameters were optimized using response surface methodology (RSM), with ethanol concentration, liquid-to-solid ratio, and extraction time as independent variables, and RA, CA, and FA contents, determined by HPLC, as response variables. The crude extract was further partitioned into n -hexane, chloroform, ethyl acetate, n -butanol, and aqueous fractions, which were evaluated for antioxidant, antimicrobial, and anti-inflammatory activities using DPPH radical scavenging, agar-well diffusion, and nitric oxide inhibition assays, respectively. The major phenolic acids were subsequently isolated and structurally characterized by MS, FT-IR, Raman, and NMR analyses.

Results

The optimized MUAE conditions were 50% ethanol, a liquid-to-solid ratio of 1:15, and an extraction time of 40 min, under which RA, FA, and CA reached 8.356, 3.92, and 0.125 mg/g, respectively. Among the fractions, the n -butanol extract was the most enriched in phenolics, with RA representing 58.2% of the total phenolic compounds, and it displayed the strongest antioxidant, anti-inflammatory, and antimicrobial activities.

Conclusion

These findings demonstrate that MUAE is an effective and environmentally favorable strategy for recovering bioactive phenolic acids from H.foertherianum , particularly RA-rich fractions.

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