以丹参茎叶总酚酸为底物的丹酚酸A化学转化研究及其抗氧化活性

Chemical Transformation of Salvianolic Acid A from the Total Phenolic Acid of Salvia miltiorrhiza Stems and Leaves and Its Antioxidant Activity

目的:优选丹参茎叶总酚酸为底物转化丹酚酸A的工艺参数,并进一步评价其转化前后的抗氧化活性。方法:以丹酚酸A转化率为指标,考察不同酸、pH值、反应时间、反应温度、底物浓度(以丹酚酸B计)等因素对转化率的影响,结合正交试验结果,优选丹参茎叶酚酸部位化学转化工艺,对转化前后总酚酸的抗氧化活性进行评价。结果:优选的转化工艺为:盐酸调节pH值为3,底物浓度(以丹酚酸B计)15 mg/mL,反应温度135℃,反应时间2 h,转化率可达89%,转化后其化学构成发生改变,丹酚酸A、丹参素、原儿茶醛含量显著提高。丹参茎叶总酚酸转化后对DPPH·和ABTS自由基的IC_(50)值分别为(3.00±0.16)mg/mL、(16.88±0.32)mg/mL,FRAP法为(1.15±0.03)mmol FeSO_(4),较转化前表现出更优的抗氧化能力。结论:采用化学转化方法可有效实现丹参茎叶总酚酸高效转化为高附加值的丹酚酸A,提升其资源利用价值。

Objective:To optimize the technological parameters of salvianolic acid A transformation from total phenolic acids in stems and leaves of Salvia miltiorrhiza,and to further evaluate the antioxidant activity of salvianolic acid A before and after transformation.Methods:Taking the conversion rate of salvianolic acid A as the index,the effects of different acids,pH value,reaction time,reaction temperature and substrate concentration(calculated by salvianolic acid B)on the conversion rate were investigated.Combined with the results of orthogonal test,the chemical transformation process of salvianolic acid in the stems and leaves of Salvia miltiorrhiza was optimized,and the antioxidant activity of total phenolic acid before and after transformation was evaluated.Results:The optimal transformation process was that pH value was adjusted to 3 by hydrochloric acid,substrate concentration(salvianolic acid B)was 15 mg/mL,135℃,2 h,and the transformation rate was 89%,the contents of salvianolic acid A,danshensu and protocatechuic aldehyde were significantly increased.The total phenolic acids after transformation showed moderate antioxidant activities in DPPH·assay(IC50 value of 3.00±0.16 mg/mL),ABTS test(IC_(50)value of 16.88±0.32 mg/mL)and FRAP method(1.15±0.03 mmol FeSO_(4)).Conclusion:Chemical transformation can effectively realize the efficient transformation of total phenolic acids in stems and leaves of Salvia miltiorrhiza into salvianolic acid A with high added value,and improve its resource utilization value.