Variation of essential oil content and antioxidant activity of Lonicera species in different sites of China

Flos Lonicerae (FL) was widely planted in China as a kind of pharmaceutical resource. In our research, the variations in content and antioxidant activity of essential oil of FL from five different sites of China were investigated. The results revealed that the essential oil content of samples varied over the range of 0.288   ±   0.015% to 0.387   ±   0.016%. The essential oil antioxidant activity of samples were also determined by scavenging activity against 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid ammonium salt) (ABTS), ferric reducing/antioxidant power (FRAP) test and β-carotene-linoleic acid bleaching test. The results indicated that the sample from Shaoyang showed better antioxidant activity than the others. And the β-carotene-linoleic acid bleaching activity could reach 92.31%, when the concentration of the sample from Shaoyang was 4   mg/mL, indicating that the sample from Shaoyang possessed excellent antioxidant activity. The chemical compositions of the essential oil were finally identified by GC–MS, and more than 20 compounds were identified. Principal component analysis was also performed to investigate the difference of the essential oil samples.