Evaluation, prediction and optimization the ultrasound-assisted extraction method using response surface methodology: antioxidant and biological properties of Stachys parviflora L.

Objective(s):To optimize the extraction method using response surface methodology, extract the phenolic compounds, and identify the antioxidant and biological properties of Stachys parviflora L.  extracts. Materials and Methods: Maceration and ultrasound-assisted extraction (UAE) (۴, ۷, ۱۰ min treatment time, ۴۰, ۷۰, ۱۰۰ % high-intensity and ۶۰, ۸۰, ۱۰۰ % (v v-۱) methanol purity) were applied to obtain the extracts. SEM was conducted to provide the microstructure of the extracted plant. MICs (colorimetric assay), MFCs (colony diameter), total phenolic content, total flavonoid content, radical scavenging capacity and extraction efficiency were determined. HPLC analysis was applied to measure the existent phenolic compounds. Results: A quadratic model (۴ min treatment time, ۷۴.۵ % high-intensity and ۷۴.۲ % solvent purity) was suggested as the best (TPC: ۲۰.۸۹ mg GAE g-۱ d.m., TFC: ۶.۲۲ mg QEs g-۱ d.m., DPPH IC۵۰: ۲۱.۸۶ µg ml-۱ and EE: ۱۱۳.۶۵ mg g-۱ d.m.) UAE extraction model. The optimized UAE extract was generally more effective against Gram-positive microorganisms (MIC: ۱۰-۲۰; MBC: ۱۰-۴۰ (mg ml-۱)) than Gram-negative ones (MIC: ۴۰; MBC: >۴۰ (mg ml-۱)). Moreover, it (MGI: ۲.۳۲-۱۰۰ %) revealed more anti-mold activity than maceration (MGI: Conclusion: RSM optimization was successfully applied for UAE from S. parviflora. The considerable antioxidant and biological properties were attributed to the phenolic compounds.

Keywords:

Antioxidant , Biological properties , HPLC , RSM , Stachys parviflora L , UAE