Abstract: The extraction of plamitoleic acid (POA) from sea buckthorn fruit oil (SBFO) by urea complexation followed by molecular distillation was optimized using a combination of one-factor-at-a-time method and response surface methodology, and the fatty acid composition of the product was analyzed by gas chromatography (GC). Then, an insulin resistance model was established in HepG2 cells treated with high concentration of insulin and was used to explore the ability of the extract to improve insulin resistance. The results showed that the optimal extraction conditions were as follows: ratio of urea to substrate 1.98:1 (g/g), ratio of solvent to urea 4.03:1 (mL/g), and reaction time 12.15 h for urea complexation; feeding rate 0.84 mL/min, scraping rate 116.02 r/min, and distillation temperature 99.75 ℃ for molecular distillation. The results of GC analysis showed that the plamitoleic acid content was significantly increased up to 72.19% (predicted value of 68.02%) under these optimal conditions, indicating that the established method could be used for the enrichment and purification of POA from SBFO. In vitro experiments showed that the palmitoleic acid at 100 mol/L could significantly improve the level of glycogen synthesis, and alleviate the decrease of glucose consumption caused by insulin resistance at 200 mol/L, proving that a certain dose of sea buckthorn plamitoleic acid could alleviate insulin resistance.

Key words: plamitoleic acid from sea buckthorn fruit oil, extraction, response surface methodology, insulin resistance