Natural Xanthones from Garcinia mangostana with Multifunctional Activities for the Therapy of Alzheimer's Disease

Natural xanthones have diversity pharmacological activities. Here, a series of xanthones isolated from the pericarps of Garcinia mangostana Linn, named alpha-Mangostin, 8-Deoxygartanin, Gartanin, Garciniafuran, Garcinone C, Garcinone D, and gamma-Mangostin were investigated. Biological screening performed in vitro and in Escherichia coli cells indicated that most of the xanthones exhibited significant inhibition of self-induced beta-amyloid (A beta) aggregation and also beta-site amyloid precursor protein-cleaving enzyme 1, acted as potential antioxidants and biometal chelators. Among these compounds, alpha-Mangostin, Gartanin, Garcinone C and gamma-Mangostin showed better antioxidant properties to scavenge Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) free radical th can Trolox, and potent neuroprotective effects against glutamate-induced HT22ell death partly by up-regulating HO-1 protein level and then scavenging reactive oxygen species. Moreover, Gartanin, Garcinone C and gamma-Mangostin could be able to penetrate the blood-brain barrier (BBB) in vitro. These findings suggest that the natural xanthones have multifunctional activities against Alzheimer's disease (AD) and could be promising compounds for the therapy of AD.