*2.2. Isolation of the Essential Oils*

The essential oil was extracted through steam distillation by referring to the Chinese Pharmacopoeia 2020 edition (part 4) volatile oil determination method (General Principle 2204) for determination. We added 500 g of dried turmeric with an appropriate amount of water and a few glass beads into a 1000 mL round-bottom flask, treating the solution by slowly heating it to a boil, followed by keeping it slightly boiling for 6 h. The upper oil phase (the crude essential oil of turmeric) was gathered and sealed and stored away from light at 4 ◦C for further use.

### *2.3. Extraction Yield*

After extraction, the extraction rate of volatile oil is calculated according to the following formula:

$$\text{Extraction yield (\%)}=\text{m}\_1/\text{m}\_0 \times 100\tag{1}$$

where m1 is the total mass of the extracted oil, and m0 is the initial mass of the turmeric used in each extraction.
