Analysis of Constituents and Bacteriostatic Activity of Essential Oil Extracted from Sea Buckthorn Seeds by Different Methods

Sea buckthorn is a homologous plant listed in Chinese pharmacopoeia. The Essential Oils (EOs) of Sea Buckthorn Seeds (SBTS) are widely used in medicine and health products in China, Russia and other countries. The extraction methods of SBTS with advantages of low cost, high yield and high activity have attracted considerable attention. In this study, the extraction rate, chemical compositions and antibacterial activity of EOs from SBTS from Jilin Province extracted by Hydrodistillation (HD), Microwave-Assisted HD (MAHD) and Enzyme-Assisted HD (EAHD) were compared, so as to provide references for the preparation and application of EOs from SBTS. The results showed that the extraction rates of EOs from SBTS were (0.457±0.062%) when extracted by EAHD. The extraction rate of EAHD was significantly higher, with values reaching 2.3 and 1.4 times that of HD and MAHD, respectively. A total of 18,26 and 26 volatile compounds were identified by Gas chromatography-mass spectrometer analysis. The three EOs were mainly composed of acid, ester and alkane and the acid component accounted for more than 50% of total, with the highest acid proportion occupied by HD (63%). The minimum inhibitory concentration of the EOs from SBTS extracted by HD, MAHD and EAHD against Bacillus subtilis, Bacillus pumilus and Staphylococcus aureus was determined simultaneously. The minimum inhibitory concentration of EOs from SBTS extracted by HD against Bacillus subtilis was 0.78 mg/mL, which is better than EOs extracted by MAHD and EAHD and consistent with the positive control. The minimum inhibitory concentration of EOs extracted by the three extraction methods to Bacillus pumilus was 1.56 mg/mL, which was lower than the positive control. The minimum inhibitory concentration of EOs from SBTS against Staphylococcus aureus was 3.12 mg/mL, which was lower than that of the positive control but better than that of EOs extracted by MAHD and EAHD. Based on the experimental results, the different extraction methods have a great influence on the extraction rate, chemical composition and activity of EOs. Although the extraction rate of EOs from SBTS extracted by HD was lower, it had low cost, more active components and better activity. Thus, these EOs can be developed as a natural antibacterial agent in the future.