Protective Effects of 2-Dodecyl-6-Methoxycyclohexa-2,5 -Diene-1,4-Dione Isolated from Averrhoa Carambola L. (Oxalidaceae) Roots on Neuron Apoptosis and Memory Deficits in Alzheimer's Disease

AbstractBackground/Aims: The roots of Averrhoa carambola L. ( Oxalidaceae ) have long been used as a traditional Chinese medicine for the treatment of headaches, vomiting, coughing and hangovers. 2-dodecyl-6-methoxycyclohexa-2, 5-1, 4-dione (DMDD) has been isolated from A. carambola L. roots, and this study was carried out to investigate the potential beneficial effects of DMDD on neuron apoptosis and memory deficits in Alzheimer's disease. Methods: The effects of a DMDD on learning and memory in APP/PS1 transgenic AD mice in vivo were investigated via Morris water maze and Y-type electric maze tests. In vitro , Cell viability was assessed by CCK-8. Apoptosis was assessed by Annexin V-FITC/PI flow cytometry assay, and transmission electron microscopy assay. Relative quantitative real-time PCR and Western blot were used to determine the expressions of genes and proteins. Results: The spatial learning and memory deficit, fear memory deficit, as well as apoptosis and loss of neuron in hippocampal area of APP/PS1 mice were reversed by DMDD in APP/PS1 transgenic AD mice. DMDD protected against the Aβ1-42-induced apoptosis, loss of mitochondria membrane potential, induction of pro-apoptotic Bcl-2 family protein Bax, reduction of anti-apoptotic Bcl-2 family proteins Bcl-2, and activation of Caspase-3, and -9 in PC-12 cells. The Bcl-2/Bax ratio was also increased in DMDD-pretreated PC-12 cells in vitro and APP/PS1 mice in vivo . Conclusion: DMDD has potential benefit on treating learning and memory deficit in APP/PS1 transgenic AD mice, and its effects may be associated with reversing the apoptosis of neuron via inhibiting Bax/Bcl-2 mediated mitochondrial membrane potential loss.