title: Subcritical ethanol extraction of flavonoids from Moringa oleifera leaf and evaluation of antioxidant activity.
abstract: A large-scale process to extract flavonoids from Moringa oleifera leaf by subcritical ethanol was developed and HPLC-MS analysis was conducted to qualitatively identify the compounds in the extracts. To optimize the effects of process parameters on the yield of flavonoids, a Box-Behnken design combined with response surface methodology was conducted in the present work. The results indicated that the highest extraction yield of flavonoids by subcritical ethanol extraction could reach 2.60% using 70% ethanol at 126.6°C for 2.05h extraction. Under the optimized conditions, flavonoids yield was substantially improved by 26.7% compared with the traditional ethanol reflux method while the extraction time was only 2h, and obvious energy saving was observed. FRAP and DPPH assays showed that the extracts had strong antioxidant and free radical scavenging activities.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Tianjin Academy of Environmental Sciences, Tianjin 300191, China; Tianjin United Environmental Engineering Design Company Limited, Tianjin 300191, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Gao
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. Electronic address: dinghui@tju.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Ding
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Shejiang
authors.initials: S
authors.lastname: Liu
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Han
authors.affiliation: School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
authors.forename: Jianzhou
authors.initials: J
authors.lastname: Gui
authors.affiliation: School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000431:Ethanol / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D029588:Moringa oleifera / Q000737:chemistry; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010936:Plant Extracts; D000431:Ethanol
keywords: Antioxidant property; Flavonoids; Moringa oleifera leaf; Response surface methodology; Subcritical ethanol extraction