Apocynin, also known as acetovanillone, is a natural organic compound related to vanillin. It has been isolated from a variety of plant sources. Metabolites of apocynin are able to block the activity of NADPH oxidase, thus giving apocynin antioxidant and anti-inflammatory capabilities. Effects of apocynin on the concentration of reactive oxygen and nitrogen species in patients with asthma and chronic obstructive pulmonary disease were investigated in phase I clinical trials. In preclinical models, it was found that apocynin provides neuroprotective effects in models of stroke and Parkinson's disease.

ON-123300 is a potent and multi-targeted kinase inhibitor with potential application for brain tumor chemotherapy. ON123300 strongly inhibits Ark5 and CDK4, as well as growth factor receptor tyrosine kinases such as β-type platelet-derived growth factor receptor (PDGFRβ). ON123300 inhibited U87 glioma cell proliferation and reduced phosphorylation of Akt, yet it also unexpectedly induced Erk activation, both in a dose- and time-dependent manner that subsequently was attributed to relieving Akt-mediated C-Raf S259 inactivation and activating a p70S6K-initiated PI3K-negative feedback loop. ON123300 demonstrated high brain and brain tumor accumulation and favorable pharmacokinetic characteristics.