Triptolide and tripchlorolide exert beneficial effects on synapses in Alzheimer’s disease mice, and the underlying mechanism may be related to DNA methylation, for the compounds can inhibit the DNA methylation of Nlgn1 promoter in the hippocampus, and thus increase the expression of gene Nlgn1 (Lu et al., 2019). Here, NLGN1 is linked to early-onset autosomal dominant Alzheimer disease.