In addition, tanshinone IIA inhibits the transcription and expression of genes encoding inducible nitric oxide synthase (iNOS), metalloproteinase (MMP)-2, and human nuclear factor (NF-κBp65) pathway, thereby inhibiting the occurrence of neuroinflammation and reducing AD risk (Jiang P. et al., 2014). Here, NOS2 is linked to Alzheimer disease.