Microwave-assisted natural deep eutectic solvent-based system for sustainable eritadenine extraction from shiitake mushroom (Lentinula edodes)

Shiitake (Lentinula edodes) mushrooms contain a significant level of eritadenine, a cholesterol-lowering compound. However, volatile organic solvents such as methanol are commonly used in the extraction of eritadenine. To overcome this disadvantage, in the present study, microwave-assisted natural deep eutectic solvents (NADESs) extraction was tested for the extraction of eritadenine. The efficiency of NADESs was compared with benchmark solvents (water, aqueous ethanol, aqueous methanol). NADES, composed of betaine and sorbitol, demonstrated superior efficiency in the extraction of eritadenine. Based on the results obtained from preliminary experiments, microwave-assisted extraction was optimized using a statistical optimization method. A microwave power of 300 W and an extraction time of 15 s were established as optimal conditions with an eritadenine content of 10.63 mg/g dry weight (DW). Further comparisons using NADES revealed the superiority of microwaves over homogenization and stirring methods. The highest level of eritadenine was measured with the microwave-assisted method (10.56 mg/g DW), followed by homogenization (7.22 mg/g DW) and stirring (1.03 mg/g DW). A similar trend was detected in the total phenolic content of the extracts (microwave: 8.27 mg GAE/g DW, homogenization: 2.32 mg GAE/g DW, and stirring: 0.46 mg GAE/g DW). The DPPH and ABTS antioxidant capacities of the extracts ranged from 1.18 to 29.40 mg TE/g DW and 2.42-34.69 mg TE/g DW, respectively. According to the sample preparation metric of sustainability tool, the microwave-assisted approach for the extraction of eritadenine was more sustainable due to the short extraction time. Overall, NADES combined with microwave technology represents an efficient approach for recovering eritadenine, enhancing extraction efficiency and sustainability from shiitake mushrooms.