Solvent-free microwave extraction of essential oil and hydrosol from fresh leaves of Cinnamomum burmannii (Nees et T. Nees) Blume after screw extrusion treatment and evaluation of pancreatic lipase inhibitory activities in vitro compared to its main components

One of the most significant sources of commercial camphor oil is the essential oil of Cinnamomum burmannii (Nees et T. Nees) Blume leaves, which has been manufactured using a variety of distillation techniques, including hydrodistillation and microwave-assisted hydrodistillation. In this study, we employed solvent-free microwave extraction (SFME) to recover hydrosol and essential oil from fresh C. burmannii leaves that had undergone screw extrusion. An optimum yield of 12.35 ± 0.62 mL/kg DW of essential oil was obtained by optimizing the major SFME contributing parameters using a face-centered central composite design (FCCCD). By using SFME, the influence of microwave irradiation power on the yield and quality of the essential oil of fresh leaves of C. burmannii was examined. With the aid of first- and second-order kinetic equations, SFME was contrasted with hydrodistillation and dry distillation. A total of 32 components were detected in the essential oil, and 22 components were detected in the hydrosol obtained by SFME under the optimized conditions. The main components of the essential oil were 1,8-cineole (21.67%), borneol (17.37%) and α-terpineol (7.45%), in descending order, and the main components of the hydrosol were trans-2-hydroxycinnamic acid (21.45%), borneol (22.07%), 1,8-cineole (13.65%) and α-terpineol (11.93%). 1,8-Cineole and borneol were the two components with the highest influence on hierarchical clustering, according to principal component analysis and heatmap analysis. Moreover, box-whisker plots were used to determine and compare the inhibitory activities of the essential oil and its three primary constituents against pancreatic lipase. The outcomes demonstrated that 1,8-cineole played a critical role in the essential oil's ability to inhibit pancreatic lipase, and they also demonstrated a positive correlation between the concentration and the amount of inhibition activity.