Analgesic Activity of Jin Ling Zi Powder and Its Single Herbs: A Serum Metabonomics Study

To compare the analgesic effect of Jin Ling Zi Powder (JLZ) and its two single herbs.

The hot plate method was used to induce pain. Totally 36 mice were randomly divided into 6 groups by a complete random design, including control, model, aspirin (ASP, 0.14 g/kg body weight), JLZ (14 g/kg body weight), Corydalis yanhusuo (YHS, 14 g/kg body weight), and Toosendan Fructus (TF, 14 g/kg body weight) groups, 6 mice in each group. The mice in the control and model groups were given the same volume of saline, daily for 2 consecutive weeks. At 30, 60, 90, and 120 min after the last administration, the pain threshold of mice in each group was measured, and the improvement rate of pain threshold was calculated. Serum endogenous metabolites were analyzed by gas chromatography-mass spectrometry (GC-MS).

There was no statistical difference in pain threshold among groups before administration (P>0.05). After 2 weeks of administration, compared with the model group, the pain threshold in JLZ, YHS, TF and ASP groups were increased to varying degrees (P<0.05). JLZ had the best analgesic effect and was superior to YHS and TF groups. A total of 14 potential biomarkers were screened in serum data analysis and potential biomarkers levels were all reversed to different degrees after the treatment with JLZ and its single herbs. These potential biomarkers were mainly related to glyoxylate and dicarboxylate metabolism, glycine, serine and threonine metabolism, valine, leucine and isoleucine biosynthesis, aminoacyl-tRNA biosynthesis and inositol phosphate metabolism.

The analgesic mechanism of JLZ and YHS was mainly due to the combination of glycine and its receptor, producing post-synaptic potential, reducing the excitability of neurons, and weakening the afferent effect of painful information.