姜黄素降解产物的分离鉴定及姜黄素的稳定性考察

Isolation and identification of degradation products of curcumin and study of stability of curcumin

目的更好地开发利用姜黄素,并对其降解产物进行质量控制。方法利用NMR谱对姜黄素在丙酮溶液中、碱溶液中的降解产物进行鉴定;利用紫外分光光度法检测不同条件下姜黄素的稳定性。结果从姜黄素的日光照射降解产物中分得7个化合物,分别鉴定为香草醛(vanillin,1)、香草酸(vanillic acid,2)、2-羟基-香荚兰乙酮(2-hydroxyacetovanillone,3)、原儿茶醛(protocatechualde-hyde,4)、乙酰阿魏酮(acetoferulone,5)、反式阿魏酸(trans-ferulic acid,6)、顺式阿魏酸(cis-ferulicacid,7);从姜黄素的碱溶液降解产物中分得3个化合物,分别鉴定为香草醛、香草酸、反式阿魏酸。姜黄素在pH10以上的碱性溶液中、光照条件下、在路易斯碱溶液中吸光度减小速度明显加快。结论共分得7个已知的降解产物;姜黄素在酸性溶液中较稳定,在碱性溶液中稳定性下降。

Objective To study the stability and degradation products of curcumin. Methods The stabilities of curcumin in different conditions were examined by using UV spectrophotometer. The degradation products were isolated by open ODS and HPLC. Their structures were determined on the basis of physicochemical properties and spectroscopic methods such as ^1H-NMR, ^3C-NMR, and UV spectrum. Results It was found that when pH value was higher than 10, the speed of degradation was increased;and when water was added to the solution or the solution was Lewis base, the stability of curcumin was decreased. The isolated compounds from photodecomposition were identified as vanillin （ 1 ）, vanillic acid （2）, 2-hydroxyacetovanillone （3）, protocatechualdehyde （4）, acetoferulone （ 5 ）, trans-ferulic acid （6）, cis-ferulic acid （ 7 ） ; the compounds from alkaline solution were identified as vanillin（ 1 ）, vanillic acid（2 ）, trans-ferulic acid（ 6 ）. Conclusions A total of seven known compounds are isolated. Curcumin in acidic solution is more stable than in alkaline solution.