The Essential Oils of Litsea cubeba (Lour.) Pers. Fruit Extracted from Different Temperature Ranges Exhibit Distinct Chemical Compositions and Biologic Activities

Abstract

Objective: This study presents a stepwise-heating hydrodistillation to collect the fruit of Litsea cubeba essential oil (EO) from different temperature ranges. The differences between the qualitative and quantitative properties of these EOs and the effects of these differences on the antioxidant and antibacterial activity of the EOs were investigated. Methods: The chemical composition of EOs was analysed by means of Gas Chromatography-Mass Spectroscopy analysis (GC-MS); moreover, 2,2-diphenyl-1-picrylhydrazyl (DPPH) was made to evaluate the antioxidant activity. In addition, disk diffusion method and minimum inhibitory concentration (MIC) were employed to evaluate the antimicrobial activities against Staphylococcus aureus and Escherichia coli. Results: The total yield of EO was 4.95% (v/w), with the EO collected at 95 °C to 98 °C (LCF-1), 98 °C to 99 °C (LCF-2), and 99 °C to 100 °C (LCF-3) accounting for 8.60%, 84.83%, and 6.53% of this yield, respectively. A total of 14, 17, and 19 compounds were identified, representing 98.17%, 98.69%, and 97.52% of the total oil content of LCF-1, LCF-2, and LCF-3, respectively. These fractions primarily contained limonene (11.46%−31.57%), neral (19.75%−33.57%), and geranial (24.63%−40.38%). LCF-3 had the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, LCF-2 had the strongest inhibitory effect on S. aureus growth, and LCF-1 and LCF-2 had a stronger ability to inhibit E. coli than did LCF-3. In addition to the 3 main ingredients aforementioned, some minor components, such as verbenol, β-caryophyllene, and α-pinene that may also affect the antibacterial and antioxidant activities of these EO fractions. Conclusion: The study demonstrated that the different in the qualitative and quantitative components of EOs of Litsea cubeba fruit extracted from three temperature ranges, resulting in exhibiting the distinct expression of antioxidative and antibacterial activities of three EO fractions. Therefore, this paper provides an innovative extraction strategy for EOs to recover the EO in specific temperature range according to the biological activity required.