Study on the targeted regulation of Scutellaria baicalensis leaf on glutamine–glutamate metabolism and glutathione synthesis in the liver of d-gal ageing rats

Abstract Objectives Scutellaria baicalensis leaf (SLE), the above-ground part of the traditional Chinese medicine Scutellaria baicalensis Georgi, is rich in resources and contains a large number of flavonoids with anti-inflammatory, antioxidant and neuroprotective functions. The present study evaluated the ameliorative effects and related mechanisms of SLE on d-gal-induced ageing rats, providing a theoretical basis for the exploitation of SLE. Methods This experiment investigated the mechanism of SLE for anti-ageing by non-targeted metabonomics technology combined with targeted quantitative analysis and molecular biology technology. Key findings Non-targeted metabonomics analysis showed that 39 different metabolites were screened out. Among them, 38 metabolites were regulated by SLE (0.4 g/kg), and 33 metabolites were regulated by SLE (0.8 g/kg). Through enrichment analysis, glutamine–glutamate metabolic pathway was identified as the key metabolic pathway. Subsequently, the results of targeted quantitative and biochemical analysis displayed that the contents of key metabolites and the activities of enzymes in glutamine-glutamate metabolic pathway and glutathione synthesis could be regulated by SLE. Furthermore, the results of Western blotting indicated that SLE significantly modulated the expression of Nrf2, GCLC, GCLM, HO-1, and NQO1 proteins. Conclusion To sum up, the anti-ageing mechanism of SLE was related to glutamine-glutamate metabolism pathway and Nrf2 signalling pathway.