OBJECTIVE： To prepare Zingiber officinale oil microcapsules and to evaluate its quality. METHODS： Z. officinale oil microcapsules were prepared by spray drying method with sodium starch octenyl succinate as capsule material. The preparation technology was optimized by orthogonal test with mixing temperature of capsule material and capsule core， mass ratio of capsule material and capsule core， stirring speed as factors， using encapsulation efficiency as index. The drug loading， encapsulation efficiency， appearance， particle size distribution and stability of light， heat and humidity （using iodine value and peroxide value as indexes） were evaluated. RESULTS： The optimal preparation technology of Z. officinale oil microcapsules was that the mixing temperature of capsule material and core was 60 ℃； mass ratio of capsule material and capsule core was 10 ∶ 1； stirring speed was 12 000 r/min. Average drug-loading amount and encapsulation efficiency of Z. officinale oil microcapsules prepared by optimal technology were 17.97％ and 73.57％ （n＝3）. The morphology of Z. officinale oil microcapsules was round， smooth， non-sticky and uniform in size distribution. The average diameter of microcapsules was （6.30±0.27） μm. Under light， heat and humidity conditions， the iodine value and peroxide value of Z. officinale oil microcapsules changed slightly. CONCLUSIONS： The optimal preparation technology of Z. officinale oil microcapsules is simple and reproducible. The prepared microcapsules have good encapsulation efficiency， high drug loading amount and good stability.

OBJECTIVE To investigate the effects and potential mechanism of paeoniflorin on oxidative stress of ulcerative colitis （UC） mice based on adenosine monophosphate-activated protein kinase （AMPK）/nuclear factor-erythroid 2-related factor 2 （Nrf2） pathway. METHODS Male BALB/c mice were randomly divided into control group， model group， inhibitor group （AMPK inhibitor Compound C 20 mg/kg）， paeoniflorin low-， medium- and high-dose groups （paeoniflorin 12.5， 25， 50 mg/kg）， high- dose of paeoniflorin+inhibitor group （paeoniflorin 50 mg/kg+Compound C 20 mg/kg）， with 8 mice in each group. Except for the control group， mice in all other groups were given 4% dextran sulfate sodium solution for 5 days to establish the UC model. Subsequently， mice in each drug group were given the corresponding drug solution intragastrically or intraperitoneally， once a day， for 7 consecutive days. The changes in body weight of mice were recorded during the experiment. Twenty-four hours after the last administration， colon length， malondialdehyde （MDA） content， and activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） in colon tissues were measured； histopathological morphology of colon tissues， tight junctions between intestinal epithelial cells， and histopathological scoring were all observed and evaluated； the mRNA expressions of AMPK and Nrf2， as well as the protein expressions of heme oxygenase-1（HO-1）， occludin and claudin-1， were all determined in colon tissue. RESULTS Compared with model group， paeoniflorin groups exhibited recovery from pathological changes such as inflammatory cell infiltration and crypt damage in the colon tissue， as well as improved tight junction damage between intestinal epithelial cells. Additionally， significant increases or upregulations were observed in body weight， colon length， activities of SOD and GSH-Px， phosphorylation level of AMPK， and protein expression of Nrf2， HO-1， occludin， claudin-1， and mRNA expressions of AMPK and Nrf2； concurrently， MDA content and histopathological scores were significantly reduced （P＜ 0.05 or P＜0.01）. In contrast， the inhibitor group showed comparable （P＞0.05） or worse （P＜0.05 or P＜0.01） indicators compared to the model group. Conversely， the addition of AMPK inhibitor could significantly reverse the improvement of high- dose paconiflorin （P＜0.01）. CONCLUSIONS Paeoniflorin can repair intestinal epithelial cell damage in mice， improve tight junctions between epithelial cells， upregulate the expression of related proteins， and promote the expression and secretion of antioxidant-promoting molecules， thereby ameliorating UC； its mechanism may be associated with activating AMPK/Nrf2 antioxidant pathway.