1HNMR测定辽宁紫草（Lithospermum erythrorhizon Sieb. et Zucc）中紫草素对映体纯度

Shikonin and alkannin, a pair of chiral enantiomer, have been found to demonstrate a wide range of significant biological activity. Many studies have also shown that the enantiomeric excess (e.e.) of shikonin or alkannin from the roots of boraginaceae varied significantly, however, the current qualitative and quantitative determination of the e.e. mainly came to the aid of the optical spectrophotometry and liquid chromatography, which there are many disadvantages to influence their accuracy. In the paper, we first introduced S-(-)-α- methoxy-α- (trifluoromethyl)- phenyl -acetic acid to hydroxyl group in the side chain of shikonin isolated form Lithospermum erythrorhizon Sieb. et Zucc to form Mosher esters, and then used 1HNMR to determine the relative intensity of the resulting peak of H-1' as a result of chemical shift non-equivalence, and thereby to acquire the e.e of shikonin prepared, and finally the accuracy of e.e. was to verify by chiral liquid chromatography.