Mulberry, the fruit of white mulberry tree (Morus alba L., Moraceae), is commonly used in traditional Chinese medicines as a sedative, tonic, laxative, and emetic. In our continuing research of the bioactive metabolites from mulberry, chemical analysis of the fruits led to the isolation of five compounds, 1-5. The compounds were identified as butyl pyroglutamate (1), quercetin 3-O-β-d-glucoside (2), kaempferol 3-O-β-d-rutinoside (3), rutin (4), and 2-phenylethyl d-rutinoside (5) by spectroscopic data analysis, comparing their nuclear magnetic resonance (NMR) data with those in published literature, and liquid chromatography-mass spectrometry analysis. The isolated compounds 1-5 were evaluated for their effects on anticancer drug-induced side effects by cell-based assays. Compound 1 exerted the highest protective effect against cisplatin-induced kidney cell damage. This effect was found to be mediated through the attenuation of phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, p38, mitogen-activated protein kinase, and caspase-3 in cisplatin-induced kidney cell damage.
Keywords: Morus alba; caspase-3; cisplatin; mitogen-activated protein kinases; mulberry; nephrotoxicity.