Z-Ligustilide, a major phthalide isolated from a widely used traditional Chinese medicine Ligusticum chuanxiong, possesses various pharmacological activities including neuroprotective, anti-inflammatory, antiproliferative and vasorelaxing effects. However, it is unstable and inclined to degrade in natural conditions, which limits its study and application greatly. In this study, degradation behavior of Z-ligustilide and its degradation products stored at room temperature under direct sunlight were investigated and structure elucidated by HPLC-UV, UPLC-QTOF-MS and NMR. Z-ligustilide degradation and total five degradation products were generated and detected. Two degradation products were unequivocally identified as senkyunolide I and senkyunolide H by comparison with reference compounds. Another two degradation products were further isolated by semi-preparative HPLC and structure elucidated as (E)-6, 7-trans-dihydroxyligustilide and (Z)-6, 7-epoxyligustilide by 1H and 13C NMR, respectively. The degradation pathways of Z-ligustilide were finally proposed. Oxidation, hydrolysis and isomerization are the major degradation reactions.

Objective:To explore the microRNA profile changes in the development of NKT cells.Methods: Differently developmental stage of NKT cells in mouse thymus were sorted by flow cytometry.Total RNA were extracted,reversely transcribed and pre-amplified.TaqMan low density microRNA assay and single real-time PCR were applied to detect the expression changes of microRNAs in the developmental process of NKT cells.Results: There were total 92 microRNAs whose expression changed significantly during the development and maturation of NKT cells.Among them,increasly expressed microRNAs were 71,including 36 microRNAs whose expression continuously increased;decreasly expressed microRNAs were 21,including 12 microRNAs whose expression continuously decreased.In addition,single real-time PCR analysis showed that the expression of Let-7f,miR-150,miR-24,miR-29 increased,while the expression of miR-223 and miR-155 decreased during the development and maturation of NKT cells.Conclusion: NKT development and maturation is accompanied by expression changes of large amount of microRNAs,indicating that specific microRNA regulates NKT development and function.