Preliminary Study On Anti-cadmium Toxicity Mechanisms Of Scutellaria Baicalensis Extract Based On Yeast Model

Cadmium does not have any biological function in higher organisms.It is generally ingested by the human body through digestion and respiratory system as well as accumulated in the body for a long period of time.Cadmium gradually causes body disorder and mainly manifests as liver and kidney dysfunction,reproductive damage,cardiovascular diseases,osteoporosis and cancer,etc.Finding effective drugs with cadmium detoxification ability and researching its mechanism has always been a research hotspot in this field.Traditional Chinese medicine used for preventing and treating cadmium toxicity is a new way due to its characteristics of short action time,good effect and less side effects.In the previous study,we investigated the recovery effect of three Chinese medicinal materials extract,Scutellaria baicalensis Georgi,Ginkgo Biloba L.,and Schisandrae chinensis?Turcz.?Baill.on the growth of yeast exposed to cadmium.As the results showed that all of the three extracts had the DPPH free radical scavenging activity with IC50 of 0.019,0.046,and 1.478 mg/m L,respectively.And only Scutellaria baicalensis Georgi and Ginkgo Biloba L.had the superoxide anion?O₂^-·?scavenging activities with IC50 of 0.137 and 2.526 mg/m L,respectively.Both three extracts had a certain antagonistic effect on tocicity of yeast exposed to 20/40?M Cd²⁺.Scutellaria baicalensis Georgi extract?SBGE?with the best results was chose to do further study.In this study,we investigated the recovery effect of SBGE on the yeast exposed to cadmium from the level of cellular processes.It was found that SBGE could reduce the intracellular reactive oxygen species?ROS?level of yeast by 71.5%and the mitochondrial membrane potential???m?by 2.3 folds under 20?M Cd²⁺condition.In addition,SBGE could reduce the intracellular reduced glutathione?GSH?level of yeast by 19.5%under 20?M Cd²⁺exposure conditions,but had no significant effect on the metabolism of superoxide dismutase?SOD?levels.Furthermore,flame atomic absorption spectrometry was used to determine the effect of SGBE on cadmium accumulation in yeast,it was found that SGBE can significantly reduce the cadmium absorption and accumulation of yeast by 68.01%.Transcriptome sequencing technology was used to analyze the anti-cadmium toxicity mechanism of SBGE on the yeast from molecular level.363 differentially expressed genes?DEGs?were found in the cadmium toxicity group and 250 DEGs were found in the cadmium added SBGE group,and the addition of SBGE contributed the expression of 248 DEGs back to normal levels.Those DEGs were defined with annotations based on the GO and KEGG classifications.We identified that these differentially expressed genes are mainly concentrated in metabolic pathways,antibiotic biosynthesis,secondary metabolite biosynthesis and amino acid synthesis and other channels,Further analysis on metabolic pathways found that cadmium exposure would lead to abnormal genes expression related to glutathione metabolism,oxidative stress,and cell-respiration in yeast.In summary,SGBE can antagonize the toxic effects of cadmium on yeast through a variety of mechanisms mainly including:reducing intracellular reactive oxygen species,maintaining normal expression of intracellular sulfur amino acid macromolecules such as glutathione,and inhibiting the destruction of mitochondrial respiratory chain caused by cadmium toxicity and reducing cadmium uptake and accumulation by yeast.The results showed that SGBE had a certain application value on anti-cadmium toxicity,and our study could provide reference for further mammals study about the anti-cadmium toxicity effect of SGBE.