Distillation time alters essential oil yield, composition and antioxidant activity of female Juniperus scopulorum trees

The objective of this study was to evaluate the effect of distillation time (DT) (1.25, 2.5, 5, 10, 20, 40, 80, 160, 240, 360, 480 minutes) on yield, oil profile and antioxidant capacity of female Juniperus scopulorum trees. Analysis of the data revealed that essential oil yields reached a maximum of 0.77% at 240 minutes DT; the concentrations of alpha-thujene, alpha-pinene, camphene, myrcene and para-cymene decreased with longer DT; and the concentrations of cis-sabinene hydrate and linalool/trans-sabinene hydrate reached maximum at 40 minutes DT, whereas that of pregeijerene-B, delta-carene reached maximum at 240 minutes DT. The concentrations of alpha-terpinene, limonene, gamma-terpinene and 4-terpineol reached their maximum at 360 minutes DT, whereas terpinolene, alpha-eudesmol/ beta-eudesmol and 8-alpha acetoxyelemol reached maximum at 480 minutes DT. The yield of various essential oil constituents increased with increasing DT and reached maximum at 240 minutes or longer. The antioxidant capacity of J. scopulorum leaf essential oil increased with longer DT and was highest at 480 minutes DT. In conclusion, DT can be used as a tool to obtain an essential oil with differential composition and antioxidant activity. This paper can be used as a reference for comparing reports where different DTs were applied to extract essential oil from the leaves of female J. scopulorum.