Extraction, Chemical Composition, and Protective Effect of Essential Oil from Chimonanthus nitens Oliv. Leaves on Dextran Sodium Sulfate-Induced Colitis in Mice

Abstract

In this study, the essential oil (EO) was extracted by steam distillation from Chimonanthus nitens Oliv, and the extraction process was optimized by response surface methodology. The optimum process conditions are as follows: extraction time of 4.57 h, soaking time of 1.33 h, and solid-liquid ratio of 1 : 21.4. Under these conditions, the theoretical yield of EO is 1.5624%. The EO compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 52 chemical components were detected, among which the content of 3-(4,8-dimethylnona-3,7-dienyl)-furan was the highest, accounting for 21.43% of the total peak area. The EO showed good antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2 ${}^{\prime }$ -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and reducing power. In this study, we observed the protective effect of EO on ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) in mice. EO effectively delayed weight loss and reduced DAI score. Histological examination also observed a significant reduction in damage in the EO group. The colon length of mice in DSS group was the shortest, and the colon length of mice in EO treatment group was longer than that in model group, but shorter than that in normal group ( $\text{NOR}:8.17\pm 0.39\text{cm};\text{DSS}:5.57\pm 0.93\text{cm};\text{L}-\text{EO}:6.47\pm 0.78\text{cm};\text{M}-\text{EO}:5.98\pm 0.58\text{cm};\text{and}\text{H}-\text{EO}:6.1\pm 0.52\text{cm}$ ). The GSH activity in the L-EO and SASP groups was significantly higher than that in the DSS group ( $P<0.01$ ). SOD activity in L-EO and M-EO groups was also significantly higher than that in DSS treatment group ( $P<0.01$ ). MDA was decreased in the EO treatment groups and the SASP group (L-EO, H-EO, SASP: $P<0.01$ ; M-EO: $P<0.05$ ). MPO of EO treatment group was lower than that of model group (the L-EO group was not significant, M-EO: $P<0.05$ , H-EO: $P<0.05$ ). This study shows that EO can effectively improve the symptoms of colitis.