Essential oils are an important source of natural antioxidants and multiple methods have been established for evaluation of their overall antioxidant activity, however, the antioxidant activities of their compounds are less investigated. In the present study, the hyphenation of 2,2′-diphenyl-1-picrylhydrazyl (DPPH)-gas chromatography (GC)-mass spectrometry (MS) offline and high-speed countercurrent chromatography (HSCCC) is established for efficient screening, identification, and isolation of antioxidants from essential oils and applied to the essential oil of Curcuma wenyujin Y.H. Chen et C. Ling. Five compounds are preliminarily screened as antioxidants using DPPH-GC according to the reduction of GC peak areas of each compound after reaction with DPPH and then identified as eucalyptol (7.66%), camphor (2.34%), δ-elemene (1.15%), β-elemene (7.10%), and curzerene (15.77%) using GC-MS. Moreover, these five compounds are isolated by HSCCC using two solvent systems, n-hexane-acetonitrile-ethanol (5:3:2, v/v) and n-hexane-acetonitrile-acetone (4:3:1, v/v), and subjected to DPPH scavenging assay. Camphor, δ-elemene, and β-elemene show weak DPPH scavenging activity, while curzerene and eucalyptol show moderate DPPH scavenging activity. Notably, a significant synergistic effect on DPPH scavenging is found between curzerene and eucalyptol. The result demonstrated that off-line DPPH-GC-MS coupling CCC is an efficient method for screening, identification, and separation of antioxidant compounds in essential oil

中文翻译：

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离线DPPH-GC-MS耦合逆流色谱法用于精油中抗氧化剂化合物的筛选，鉴定和分离。

香精油是天然抗氧化剂的重要来源，并且已经建立了多种方法来评估其总体抗氧化剂活性，但是，对其化合物的抗氧化剂活性的研究较少。在本研究中，建立了2,2'-联苯-1-吡啶基肼基（DPPH）-气相色谱（GC）-质谱（MS）的脱联和高速逆流色谱（HSCCC）的高效筛选，鉴定，并从香精油中分离出抗氧化剂，并应用于姜黄温郁金的香精油Chen YH等。根据与DPPH反应后每种化合物的GC峰面积的减少，使用DPPH-GC初步筛选了五种化合物作为抗氧化剂，然后鉴定为桉树油（7.66％），樟脑（2.34％），δ-榄香烯（1.15％），使用GC-MS分析β-榄香烯（7.10％）和邻苯二酚（15.77％）。另外，这五个化合物由HSCCC使用两个溶剂系统中分离，Ñ己烷-乙腈-乙醇（5：3：2，V / V）和ñ -己烷-乙腈-丙酮（4：3：1，V / V），并进行DPPH清除测试。樟脑，δ-榄香烯和β-榄香烯显示弱的DPPH清除活性，而姜油烯和桉树油则显示中等的DPPH清除活性。值得注意的是，在姜油烯和桉树油之间发现了对DPPH清除的显着协同作用。结果表明离线DPPH-GC-MS耦合CCC是一种用于筛选，鉴定和分离精油中抗氧化剂的有效方法