Effect and mechanism of salt-processed Alpinia oxyphylla extracts on amino acid metabolism in kidney-yang deficiency polyuria rats

HAN Min; WU Shanshan; HE Xicheng; LEI Yan; WANG Ruonan

doi:10.3969/j.issn.1002-266X.2025.01.011

Abstract：Objective To investigate the effect and mechanism of intragastric administration of salt-processed Alpin-ia oxyphylla extracts liquid on amino acid metabolism in kidney-yang deficiency polyuria rats.Methods The salt-pro-cessed Alpinia oxyphylla extracts were prepared and identified by gas chromatography-mass spectrometry(GC-MS).Eigh-teen male SD rats were randomly divided into the control,model and intervention groups,with 6 rats in each group.Rats in both the model and intervention groups were given prednisone acetate solution 15 mg/kg and hydrochlorothiazide solu-tion 25 mg/kg by gavage to establish the models of kidney-yang deficiency polyuria.After successful preparation of the models,rats in the intervention group were given 1.04 g/kg salt-processed Alpinia oxyphylla extracts,and rats in the mod-el and control groups were given 0.6%Tween-80 by gavage,continuously for 1 week.The daily diet,drinking water,ex-cretion,activity and mental status of the rats were observed,and 24-h urine output was recorded.Urine was collected 6 h after the last gavage,and the differential metabolites of amino acids in urine were analyzed by GC-MS,and UREA was de-tected by UV glutamate dehydrogenase method.Blood was collected from the abdominal aorta,blood routine was detected by automatic blood cell analyser,and differential amino acid metabolites in blood were analysed by GC-MS.Serum creati-nine(CREA),AST and ALT were determined by automated biochemical analyser.Metabolic pathways were analyzed by MetaboAnalyst 6.0 online website,and metabolic pathways closely related to amino acid metabolism were screened.The correlation between amino acid metabolites and pharmacodynamic indexes was analyzed by Pearson partial least squares re-gression method.Results Six main chemical components were identified in the extracts of salt-processed Alpinia oxy-phylla,which were(-)-α-copaene,β-selinene,aristolochene,valencene,α-Copaen-15-ol and nootkatone.Compared with the control group,rats in the model group drank more water and ate less,with worse spirit,less activity and more urine in 24 h.Compared with the model group,rats in the intervention group drank less water with recovered diet,in-creased activity,decreased urine volume at 24 h and improved mental state.Compared with the control group,the model group had higher urinary UREA(P<0.05),lower serum AST(P<0.05),higher serum ALT and CREA(P<0.05),lower white blood cells(WBC)count(P<0.05),and lower urinary and serum amino acid metabolite levels(P<0.05).Com-pared with the model group,the intervention group had lower urinary UREA(P<0.05),higher serum AST(P<0.05),lower serum ALT and CREA(P<0.05),higher WBC count(P<0.05)and higher levels of urinary and serum amino acid metabolites(all P<0.05).Seventeen different amino acid metabolites were found in the urine and serum of the three groups.Five metabolic pathways were identified in the 17 different amino acid metabolites:glycine,serine and threonine metabolism,alanine,aspartate and glutamate metabolism,cysteine and methionine metabolism,histidine metabolism,glyoxylic acid and dicarboxylic acid metabolism.The 17 different amino acid metabolites were negatively correlated with 24 h urine output and serum ALT and CREA levels(all P<0.05),but were positively correlated with WBC count,UREA and serum AST levels(all P<0.05).Conclusions The salt-processed Alpinia oxyphylla can improve amino acid metab-olism and liver and kidney function in kidney-yang deficiency polyuria rats,and the difference metabolites of amino acids in urine and serum are closely related to pharmacodynamic indexes.The mechanism of action of salt-processed Alpinia oxy-phylla may regulate amino acid metabolism mainly through five metabolic pathways such as glycine,serine and threonine metabolism,alanine,aspartate and glutamate metabolism,cysteine and methionine metabolism,histidine metabolism,glyoxylic acid and dicarboxylic acid metabolism.