SIRT1 and Alzheimer disease: Another recent study (Sun et al., 2019) done in an AD rat model induced by intracerebroventricular injection of Aβ1–42, found that DHM (100 and 200 mg/kg for 21 days) improves learning and memory, decreased hippocampal neuronal apoptosis, IL-1β, IL-6, and TNF-α in serum and hippocampus and changes in different proteins such as decreased pro-apoptotic Bax and NF-κB and increased anti-apoptotic Bcl-2, pAMPK, AMPK, and SIRT1, suggesting that beneficial effects of DHM are mediated by up-regulation of AMPK/SIRT1 pathway.