Microwave-assisted method for distillation and dual extraction in obtaining essential oil, proanthocyanidins and polysaccharides by one-pot process from Cinnamomi Cortex

In the present study, a novel microwave-assisted distillation and dual extraction by one-pot process (MDDE) method was developed successfully for preparation of essential oil (EO), oligomeric proanthocyanidins (OPC), polymeric proanthocyanidins (PPC) and polysaccharides (PS) from Cinnamomi Cortex. Compared with dichloromethane and petroleum ether (30–60 °C), ethyl ether was found to be most effective in the extraction of EO and was selected as the extraction agent. Under the optimum conditions (liquid–solid ratio of 18.0 mL/g, microwave irradiation time of 38 min and microwave irradiation power of 374 W) obtained by first order kinetic models and response surface analysis with Box–Behnken design, satisfactory yields of EO (4.26 ± 0.16%), OPC (3.01 ± 0.12%), PPC (1.60 ± 0.07%) and PS (9.78 ± 0.22%) were achieved. The developed MDDE technique produced higher yields of the four constituents in a shorter time than traditional hydrodistillation, microwave-assisted hydrodistillation and simultaneous distillation–extraction methods. In addition, EO compositions obtained by MDDE and other techniques exhibited no significant changes, according to GC–MS analysis. The mean degrees of polymerization of OPC and PPC were 2.67 ± 0.10 and 13.17 ± 0.45, respectively. The proposed method could be an alternative method for enhanced extraction of volatile EO and non-volatile constituents from Cinnamomi Cortex and other natural plant materials.