Effects Of Non-emodin Anthraquinones On The Pharmacokinetics Of Emodin In Zhiheshouwu

Background:In recent years,Chinese medicines have played potential role in the treatment of various tumors.Our previous studies found that Zhiheshouwu（Polygoni multiflori radix praeparata）had anti-cancer and lowering lipid.By screening the active ingredients we found that the anthraquinones were the substance basis for the anti-cancer,including emodin,rhein,chrysophanol,physcion,aloe-emodin,emodin-8-O-β-D-glycoside,physcion-1-O-β-D-glycoside,chrysophanol-8-O-β-D-glycoside,etc.The further studies found that the inhibitory of these anthraquinones on hepatocellular carcinoma cells are various.Among them,emodin,rhein,aloe-emodin and physcion have an IC₅₀ value of less than 400μM;And the IC₅₀ value of emodin and rhein is less than or equal to 100μM.According to the quality control of Zhiheshouwu in the Chinese Pharmacopoeia（Version 2020）,the concentration of free anthraquinones（calculated as the total amount of emodin and physcion）in the ethanol extract is more than 0.1%.Due to the low content of physcion,if the content is calculated as emodin,the concentration of emodin in Zhiheshouwu would be only about 1.48μM,much smaller than the IC₅₀ value of emodin.However,Zhiheshouwu has similar effects as the emodin alone.Therefore,we speculate that anthraquinones in Zhiheshouwu might exert interacttions each other,thereby affecting the in vivo process of emodin.However,it is still unkonw how the non-emodin anthraquinones affect the process of emodin in vivo.Objective:In this research,we aimed to study the effects of rhein,chrysophanol,physcion,aloe-emodin,emodin-8-O-β-D-glycoside,physcion-1-O-β-D-glycoside and chrysophanol-8-O-β-D-glycoside in Zhiheshouwu on the pharmacokinetic of emodin.Methods:Based on the quality control of the Chiese Pharmacopoeia,high performance liquid chromatography（HPLC）was used to determine the content of 2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glycoside,emodin and physcion in Zhiheshouwu samples from different source and batches.By establishing appropriate methodologies,the linearity,precision,stability,repeatability and sample recovery rate were investigated.Moreover,determinat the content ratio of emodin and rhein,chrysophanol,physcion,aloe-emodin,emodin-8-O-β-D-glycoside,physcion-1-O-β-D-glycoside and chrysophanol-8-O-β-D-glycoside in Zhiheshouwu through HPLC-tandem mass spectrometry（HPLC-MS/MS）.Ultra-High performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）was used to determine the plasma concentration of emodin in rats over time.Results:The quality of Zhiheshouwu met the quality standars of the Chinese Pharmacopoeia（Version 2020）.The content ratios of emodin and physcion,chrysophanol,emodin-8-O-β-D-glucoside,physcion-1-O-β-D-glucoside and chrysophanol-8-O-β-D-glucoside in Zhiheshouwu were 1:1,1400:1,2:1,7:6,and 140:1,respectively.Rhein and aloe-emodin were below the limit of detection and were not detected.The pharmacokinetic results showed that physcion promote the absorption of emodin.Aloe-emodin slow down the metabolism of emodin.Emodin-8-O-β-D-glycoside decrease the absorption of emodin.The other ingredients in Zhiheshouwu promote the absorption and excretion of emodin.Conclusion:Physcion shortens the T_max of emodin,increases the V_d and CL,and promotes the absorption,distribution and excretion of emodin.Aloe-emodin increases T_1/2 and slows down the metabolism of emodin.Emodin-8-O-β-D-glycoside decrease the C_max and AUC_0-t of emodin,reduce the absorption of emodin.In short,compared with emodin alone,the other components in Zhiheshouwu shorten the T_max of emodin,increase the V_d,T_1/2 and CL,and promote the absorption and excretion of emodin.