Response Surface Methodology Optimization of Ultrasonic-Assisted Extraction of Acer Truncatum Leaves for Maximal Phenolic Yield and Antioxidant Activity

• Published in: Molecules (Basel, Switzerland) Vol. 22; no. 2; p. 232
• Main Authors: Yang, Lingguang, Yin, Peipei, Fan, Hang, Xue, Qiang, Li, Ke, Li, Xiang, Sun, Liwei, Liu, Yujun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.02.2017; MDPI
• Subjects: Acer - chemistry; Acer truncatum; Acer truncatum leaves; antioxidant activity; Antioxidants; Antioxidants - chemistry; Antioxidants - pharmacology; Chlorogenic acid; Chromatography, High Pressure Liquid; Design optimization; Ethanol; Extraction processes; Gallates; Gallic acid; Information processing; Leaves; Liquid-Liquid Extraction - methods; Phenolic compounds; phenolics; Phenols; Phenols - chemistry; Phytochemicals - chemistry; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plant Leaves - chemistry; Quercetin; Response surface methodology; Solvents; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Temperature; Temperature effects; Time Factors; Ultrasonic Waves; ultrasonic-assisted extraction; UPLC-QTOF-MS/MS; Vitamin E; Yield; Acer truncatum leaves; response surface methodology; antioxidant activity; UPLC-QTOF-MS/MS; phenolics; ultrasonic-assisted extraction
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules22020232

This study is the first to report the use of response surface methodology to improve phenolic yield and antioxidant activity of leaves extracts (ATLs) obtained by ultrasonic-assisted extraction. The phenolic composition in ATLs extracted under the optimized conditions were characterized by UPLC-QTOF-MS/MS. Solvent and extraction time were selected based on preliminary experiments, and a four-factors-three-levels central composite design was conducted to optimize solvent concentration ( ₁), material-to-liquid ratio ( ₂), ultrasonic temperature ( ₃) and power ( ₄) for an optimal total phenol yield ( ₁) and DPPH• antioxidant activity ( ₂). The results showed that the optimal combination was ethanol:water ( : ) 66.21%, material-to-liquid ratio 1:15.31 g/mL, ultrasonic bath temperature 60 °C, power 267.30 W, and time 30 min with three extractions, giving a maximal total phenol yield of 7593.62 mg gallic acid equivalent/100 g d.w. and a maximal DPPH• antioxidant activity of 74,241.61 μmol Trolox equivalent/100 g d.w. Furthermore, 22 phenolics were first identified in ATL extract obtained under the optimized conditions, indicating that gallates, gallotannins, quercetin, myricetin and chlorogenic acid derivatives were the main phenolic components in ATL. What's more, a gallotannins pathway existing in ATL from gallic acid to penta- -galloylglucoside was proposed. All these results provide practical information aiming at full utilization of phenolics in ATL, together with fundamental knowledge for further research.