title: Optimization of ultrasonic-assisted extraction and radical-scavenging capacity of phenols and flavonoids from Clerodendrum cyrtophyllum Turcz leaves.
abstract: Ultrasonic-assisted extraction (UAE) was developed to extract phenolic and flavonoid antioxidants from Clerodendrum cyrtophyllum Turcz leaves. The optimal experimental parameters for antioxidant extraction from C. cyrtophyllum leaves were measured using single-factor experimentation combined with response surface methodology (RSM). Total phenolic content (TPC) and total flavonoid content (TFC) assays were used to quantify antioxidant compounds. Next, antioxidant radical scavenging capacity was measured using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2' -azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) radicals. Optimized extraction conditions for UAE from C. cyrtophyllum leaves were as follows: 60.9% ethanol, 85.4 min, and 63.3°C for maximal TPC extraction (16.8 ± 0.2 mg GAE/g DW); 67.7% ethanol, 82.9 min, and 63.0 °C for maximal TFC extraction (49.3 ± 0.4 mg RT/g DW); 48.8% ethanol, 85.1 min, and 63.9 °C for maximal DPPH radical-scavenging capacity (86.8 ± 0.2%); and 50.6% ethanol, 81.3 min, and 63.4 °C for maximal ABTS radical-scavenging capacity (92.9 ± 0.5%). Ethanol concentration was the most important factor in the extraction process. Our work offers optimal extraction conditions for C. cyrtophyllum as a potential source of natural antioxidants.
authors.affiliation: Key Laboratory of Protection and Development Utilization of Tropical Crop Germplasm Resources, Ministry of Education, College of Material and Chemical Engineering, Hainan University, Haikou, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Zheng
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Liang
authors.forename: Donghai
authors.initials: D
authors.lastname: Li
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D032409:Clerodendrum / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D014465:Ultrasonics / Q000379:methods*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols