Arg-Phe-Asp-Ser is a cleavable ADC linker.

Syringaresinol is a lignan extracted from the sap of Lobelia longifolia with anti-inflammatory activity. syringaresinol causes vasodilation and enhances NO production through phosphorylation and dimerization of endothelial NO synthase.

Oxalic acid is a strong dicarboxylic acid occurring in many plants and vegetables. It is produced in the body by metabolism of glyoxylic acid or ascorbic acid. It is not metabolized but excreted in the urine. It is used as an analytical reagent and general reducing agent.