Loureirin C, from Chinese Dragon's Blood (Dracaena cochinchinensis S.C. Chen), is a novel selective estrogen receptor α modulator with anti-Alzheimer's disease effects

As the incidence of Alzheimer's disease (AD) continues to rise in recent years, there are few therapeutic drugs for AD treatment with limited efficacy. AD occurs twice as often in women as that in men, partially due to the low estrogen level in women after menopause. Phytoestrogens (PEs), similar to endogenous estrogens in chemical structure with neuroprotection and fewer side effects, have good development and application prospects in AD-treatment. Loureirin C is an active ingredient isolated from Chinese Dragon's Blood (CDB) with a similar structure to 17β-E2. In our study, we found that loureirin C targeted to ERα and had partial-agonistic activity using molecular docking prediction and dual-luciferase reporter assay. However, it is still unclear whether loureirin C has estrogenic effects in body, and whether exerts anti-AD effect through ERα. In this paper, the ERα selective inhibitor MPP or ERα specific small interfering RNA (siERα) mediated gene silencing technology were used. Besides, E-SCREEN method were used to evaluate the estrogen effects of loureirin C in vivo and in vitro. MTT assay, Western blot, real-time PCR technology and behaver tests was used to investigate the neuroprotective effect, cognitive function and the underlying mechanism. We found that loureirin C possessed estrogenic activity, had neuroprotective effects in AD cells and improved cognitive impairment in AD mice via ERα. Loureirin C may be a potential candidate for AD.