Abstract The main objective of the current study was to investigate the components and antioxidant activity of essential oil extracted from Purple Eleutherococcus leaves (identified as Eleutherococcus simonii) (PEEO) by hydrodistillation (HD) and solid-phase microextraction (SPME). Fourteen chemical components were identified in PEEO using gas chromatography-mass spectrometry (GC-MS), accounting for 41.21% of the total essential oil extracted by SPME, including isopropyl toluene, 4-methylene-1-(1-methylethyl) cyclohexene (3.24%), fumaric-red myrrh alcohol (2.94%), farnesol acetate (2.92%), etc. Forty-three compounds were identified by HD, accounting for 73.28% of the total essential oil extracted by HD, including α-Farnesene (3.4%), Hexadecanoic acid, methyl ester (1.28%), (α-Bisabolol (0.87%), etc. The antioxidant activity of PEEO was characterized for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, ABTS method and FRAP method, and the IC50 values were 1.125 mg/mL, 0.945 mg/mL and 0.862 mg/mL, respectively. The IC50 values for DPPH, ABTS and FRAP of essential oil were similar to those of ascorbic acid (VC; 0.853, 0.945 and 0.037 mg/mL). The results showed that the essential oil of PEEO has a high radical scavenging activity.

Abstract Purple Eleutherococcus is a selected plant grown in high mountain in Puer region of Yunnan province, which is a rich source of anthocyanins with great potential as local vegetables and tea. However, the unknown botanical origin of purple Eleutherococcus restricted its edible value. Our objectives were to identify the botanical origin of purple Eleutherococcus by DNA marker combined with the morphological characteristics, optimaze the extration method of anthocyanins by orthogonal experiment method and determine the contents of anthocyanins in purple Eleutherococcus tea. The results revealed that the purple Eleutherococcus was more closely related to Eleutherococcus simonii through comparing the sequence alignment of ITS2. Combined with the morphological characteristics of plants, purple Eleutherococcus was finally identified and classified into Eleutherococcus simonii. Through orthogonal experiment, the optimal extraction conditions of anthocyanins from purple Eleutherococcus leaves were determined: the volume fraction of ethanol was 60%, the pH of ethanol solution was 3, and the water bath temperature was 60 °C. The ultrasonic extraction was conducted for 30 min. Our study provides scientific theoretical basis for the industrial extraction of anthocyanins and provides reference value for the further development of purple Eleutherococcus in Puer region of Yunnan province in China.