The study investigated the effects of different processed products of Polygonati Rhizoma(black bean-processed Polygonati Rhizoma, BBPR; stewed Polygonati Rhizoma, SPR) on the urinary metabolites in a rat model of Alzheimer's disease(AD). Sixty SPF-grade male SD rats were randomized into a control group, a model group, a donepezil group, a BBPR group, and a SPR group, with twelve rats in each group. Other groups except the control group were administrated with D-galactose injection(100 mg·kg~(-1)) once a day for seven weeks. The control group was administrated with an equal volume of normal saline once a day for seven consecutive weeks. After three weeks of D-galactose injection, bilateral hippocampal Aβ_(25-35) injections were performed for modeling. The rats were administrated with corresponding drugs(10 mL·kg~(-1)) by gavage since week 2, and the rats in the model and control group with an equal volume of double distilled water once a day for 35 continuous days. The memory behaviour and pathological changes in the hippocampal tissue were observed. The untargeted metabolites in the urine were detected by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q/TOF-MS). Principal component analysis(PCA) and orthogonal partial least square-discriminant analysis(OPLS-DA) were employed to characterize and screen differential metabolites and potential biomarkers, for which the metabolic pathway enrichment analysis was conducted. The results indicated that BBPR and SPR increased the new object recognition index, shortened the escape latency, and increased the times of crossing the platform of AD rats in the Morris water maze test. The results of hematoxylin-eosin(HE) staining showed that the cells in the hippocampal tissue of the drug administration groups were closely arranged. Moreover, the drugs reduced the content of interleukin-6(IL-6, P<0.01) and tumor necrosis factor-α(TNF-α) in the hippocampal tissue, which were more obvious in the BBPR group(P<0.05). After screening, 15 potential biomarkers were identified, involving two metabolic pathways: dicoumarol pathway and piroxicam pathway. BBPR and SPR may alleviate AD by regulating the metabolism of dicoumarol and piroxicam.
Keywords: Alzheimer′s disease(AD); UPLC-Q/TOF-MS; black bean-processed Polygonati Rhizoma(BBPR); metabolomics; stewed Polygonati Rhizoma(SPR).