Study on the potential mechanism of Qingxin Lianzi Yin Decoction on renoprotection in db/db mice via network pharmacology and metabolomics

•This study established index component content determination method of QXLZY.•This study is the first time to elucidate that amino acid metabolism was disturbed in the kidney of db/db mice, which could be callback by QXLZY.•Untargeted metabolomics studies were preformed to investigate by UHPLC-LTQ-Orbitrap MS on urine, serum, and kidney samples.•The potential therapeutic targets of QXLZY in the treatment of DN were investigated by network pharmacological analysis.•Targeted metabolomics by UHPLC-QQQ-MS/MS was performed on urine, serum, and kidney samples for validation.