FN1 and diabetic kidney disease: This study demonstrated that combined treatment with MET and either LW or Val significantly ameliorated the renal levels of Col IV, FN, Lam, TGF-β1, and SMAD7 in DKD rats that were not fully responsive to MET monotherapy, which may be attributed to the contribution of active ingredients in Poria and Alismatis rhizome, such as PAA, PAB, PZC, PZD, PZE, PZG, PZH, PZI, PZM, PZP, and ABA presented reno-protective effect (Guo et al., 2025; Jiang et al., 2025).