姜黄素无水乙醇溶液的光稳定性研究

Study on Light Stability of Curcumin in Absolute Alcohol

目的采用UV-VIS、HPLC-UV、HPLC-MS等研究方法对姜黄素无水乙醇溶液光稳定性进行考察,研究姜黄素无水乙醇溶液的光降解动力学以及光解产物。方法姜黄素的无水乙醇溶液采用254nm紫外光照射。采用反相高效液相色谱法,以乙腈-四氢呋喃-冰醋酸-水(39∶12∶2∶47)为流动相,425nm为检测波长研究姜黄素的光降解动力学;以甲醇-冰醋酸-水(30∶3∶67)为流动相,310nm为检测波长研究姜黄素的无水乙醇溶液光降解产物动力学;HPLC-MS采用电喷雾离子源(ESI)和离子阱分析器,50-500m/z内扫描研究姜黄素无水乙醇溶液光解产物。结果UV-VIS法检测姜黄素的最大吸收峰位随着光照时间的延长向短波长移动。254nm紫外光照射24h,500,50,5mg·L-1样品的浓度越低其降解速率越快;LC-MS检测光解产物中含有香草醛。结论姜黄素无水乙醇溶液对光不稳定,在光照作用下发生降解。

OBJECTIVE To investigate light stability of curcumin in absolute alcohol solution by UV-VIS, HPLC-UV and LC-MS, and to study the photodegradation kinetics of curcumin and the degradation products. METHODS The samples were processed by ultraviolet radiation at 254 nm. The processed samples were separated on a Cl8 column. Mobile phase was acetonitrile-tetrahydrofuran- acetic acid - water （39 ： 12 ： 2 ： 47）. The contents of curcunin were determined at 425 nm. While the separation was performed with the mobile phase consisting of methanol- acetic acid- water （30 ： 3 ： 67）. The contents of photodegradation products of curcumin were investigated at 310 nm. The products of photodegradation of curcumin were characterized by LC- MS, using an electrospray ionization source （ESI） and an ion trap analyzer. RESULTS The light exposure resulted in significant changes of the UV-VIS spectral absorption of the curcumin solutions. Exposed to ultraviolet light at 254 nm （500, 50, 5 mg·L^-1）, the concentration was decreased. The lower the concentration, the faster the degradation rate. Vanillin was the main photodegradation product. CONCLUSION Curcumin in absolute alcohol exposed to light is instability.