Research of the composition and antioxidant activity of essential oil from Folium Perillaes extracted by different methods

The essential oil from Folium Perillaes was extracted by using different methods of stream distillation( SD),ultrasonic- assisted solvent- extraction( UASE),and simultaneous distillation extraction( SDE) separately,then the essential oil were identified by GC- MS,and the anti- oxidative ability of the essential oil was tested by the systems of DPPH radical scavenging,hydroxyl radical scavenging,superoxide anion radical scavenging and determination of reducing power.The result showed that: SD made the highest essential oils yields( 8.21 mg / g),followed by the UASE( 2.85 mg / g) and the SDE( 2.37 mg / g).Totally 75 compounds were identified by GC- MS( 46,26 and 27 compounds were identified by GC- MS in the extracts obtained by SD,UASE and SDE,respectively).The ketones were determined as the main component( 44.8% ~ 62.4%),especially furanones( 44.6% ~ 60.7%); the perilla ketone( 44.0% ~59.7%) was the most abundant compound,followed by 4-( 2- methylcyclohex-1- enyl)- but-2- enal( 14.2% ~ 33.7%). The result of antioxidant ability determination showed that the essential oil extracted by SD,UASE and SDE all exhibited high antioxidant activities in vitro,and positive correlation was observed between the antioxidant activity and the concentration( 1.0 ~ 3.0 mg / m L) of essential oils. In conclusion,the SD,UASE,and SDE were all proved to be the efficient method in extracting essential oil from the leaves of Perilla frutescens,and different methods made different extracting rates,chemical components,contents,as well as the different antioxidative ability of the essential oil,which provided a theoretical foundation for the further research.