Objective

2

To analyze the effect of different fixation methods on the chemical quality characteristics and antioxidant activity of

Rehmannia glutinosa

leaves， so as to lay a foundation for the selection of processing technology and quality evaluation of this medicinal materials.

Method

2

R. glutinosa

leaves was dried at 55 ℃ after treating by three fixation methods （55 ℃， boiling water， 105 ℃）， and then the fingerprints of

R. glutinosa

leaves were collected by high performance liquid chromatography （HPLC） and near infrared spectroscopy （NIRS）， and their antioxidant activities were analyzed by the 2，2-biphenyl-1-picrylhydrazyl （DPPH） method. Finally， similarity analysis， principal component analysis （PCA）， orthogonal partial least squares-discriminant analysis （OPLS-DA） and Pearson correlation analysis were used to comprehensively evaluate the quality of

R. glutinosa

leaves with different fixation methods.

Result

2

The results of HPLC and NIRS fingerprint analysis indicated that there were differences in the quality characteristics of

R. glutinosa

leaves by different fixation treatments. The comprehensive score of chemical quality of

R. glutinosa

leaves by fixation at 55 ℃ was the highest， its average comprehensive score was 2.096， followed by fixation at 105 ℃， and the lowest was fixation with boiling water. The antioxidant activity of sample with fixation at 55 ℃ was the highest， followed by fixation with boiling water. The results of OPLS-DA showed that verbascoside， isoacteoside and catalpol were the main components causing the difference in chemical quality of the leaves from the three treatments， and the three components were positively correlated with the antioxidant activity of

R

.

glutinosa

leaves. Among them， the correlation between verbascoside and antioxidant activity was extremely significant， and the isoacteoside was significant.

Conclusion

2

The chemical quality and antioxidant activity of

R. glutinosa

leaves are affected by the method of fixation， and the fixation at low temperature is the best primary processing method of

R

.

glutinosa

leaves.