Roots of Zea mays L.: As a Potential Source to Treat Sodium Oxalate-Induced Renal Cell Injury

Zea mays L. is an annual grass of the Gramineae family and is known as one of the cereal crops. Its by-products exhibited significant medicinal properties. In some regions of China, water extracts of Z. mays roots (RM) are utilized to treat kidney stones, but no research has been reported. In our present study, a bioassay-guided isolation method was used to yield five new lignans (1-5) as well as 15 known components, among which 8-15 and 17-20 were first identified from the genus. The fractions and all components were evaluated for their abilities to inhibit sodium oxalate-induced injury to human proximal tubular HK-2 cells. Fraction 50W and compounds 3, 4, and 11 exhibited the most potent activities. Further investigation indicated that these potential agents inhibited the LDH release, decreased the MDA and H₂O₂ concentrations, and increased the level of SOD2 in HK-2 cells. These results indicated that RM is a promising and valuable crop waste for further development and utilization in nephrolithiasis pharmaceutical research.