WS-5 Extract of Curcuma longa, Chaenomeles sinensis, and Zingiber officinale Contains Anti-AChE Compounds and Improves ß-Amyloid-Induced Memory Impairment in Mice.

Alzheimer's disease (AD) is linked to an extensive neuron loss via accumulation of amyloid-beta (Aß) as senile plaques associated with reactive astrocytes and microglial activation in the brain. The objective of this study was to assess the therapeutic effect of WS-5 ethanol extract in vitro and in vivo against Aß-induced AD in mice and to identify the extract's active constituents. In the present study, WS-5 exerted a significant inhibitory effect on acetylcholinesterase (AChE). Analysis by transmission electron microscopy (TEM) revealed that WS-5 prevented Aß oligomerization via inhibition of Aß 1-42 aggregation. Evaluation of antioxidant activities using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) demonstrated that WS-5 possessed a high antioxidant activity, which was confirmed by measuring the total antioxidant status (TAS). Furthermore, the anti-inflammatory properties of WS-5 were examined using lipopolysaccharide-stimulated BV-2 microglial cells. WS-5 significantly inhibited the lipopolysaccharide-induced production of nitric oxide and two proinflammatory cytokines, TNF-α and IL-6. The memory impairment in mice with Aß-induced AD was studied using the Morris water maze and passive avoidance test. Immunohistochemistry was performed to monitor pathological changes in the hippocampus and cortex region of the mouse brain. The animal study showed that WS-5 (250 mg/kg) treatment improved learning and suppressed memory impairment as well as reduced Aß plaque accumulation in Aß-induced AD. HPLC analysis identified the extract's active compounds that exert anti-AChE activity. In summary, our findings suggest that WS-5 could be applied as a natural product therapy with a focus on neuroinflammation-related neurodegenerative disorders.

Inhibition of ß-site amyloid precursor protein cleaving enzyme 1 and cholinesterases by pterosins via a specific structure-activity relationship with a strong BBB permeability.

We extracted 15 pterosin derivatives from Pteridium aquilinum that inhibited ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) and cholinesterases involved in the pathogenesis of Alzheimer's disease (AD). (2R)-Pterosin B inhibited BACE1, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with an IC50 of 29.6, 16.2 and 48.1 µM, respectively. The Ki values and binding energies (kcal/mol) between pterosins and BACE1, AChE, and BChE corresponded to the respective IC50 values. (2R)-Pterosin B was a noncompetitive inhibitor against human BACE1 and BChE as well as a mixed-type inhibitor against AChE, binding to the active sites of the corresponding enzymes. Molecular docking simulation of mixed-type and noncompetitive inhibitors for BACE1, AChE, and BChE indicated novel binding site-directed inhibition of the enzymes by pterosins and the structure-activity relationship. (2R)-Pterosin B exhibited a strong BBB permeability with an effective permeability (Pe) of 60.3×10-6 cm/s on PAMPA-BBB. (2R)-Pterosin B and (2R,3 R)-pteroside C significantly decreased the secretion of Aß peptides from neuroblastoma cells that overexpressed human ß-amyloid precursor protein at 500 µM. Conclusively, our study suggested that several pterosins are potential scaffolds for multitarget-directed ligands (MTDLs) for AD therapeutics.

Longevity and Stress Resistant Property of 6-Gingerol from Zingiber officinale Roscoe in Caenorhabditis elegans.

In order to discover lifespan-extending compounds made from natural resources, activity-guided fractionation of Zingiber officinale Roscoe (Zingiberaceae) ethanol extract was performed using the Caenorhabditis elegans (C. elegans) model system. The compound 6-gingerol was isolated from the most active ethyl acetate soluble fraction, and showed potent longevity-promoting activity. It also elevated the survival rate of worms against stressful environment including thermal, osmotic, and oxidative conditions. Additionally, 6-gingerol elevated the antioxidant enzyme activities of C. elegans, and showed a dose-depend reduction of intracellular reactive oxygen species (ROS) accumulation in worms. Further studies demonstrated that the increased stress tolerance of 6-gingerol-mediated worms could result from the promotion of stress resistance proteins such as heat shock protein (HSP-16.2) and superoxide dismutase (SOD-3). The lipofuscin levels in 6-gingerol treated intestinal worms were decreased in comparison to the control group. No significant 6-gingerol-related changes, including growth, food intake, reproduction, and movement were noted. These results suggest that 6-gingerol exerted longevity-promoting activities independently of these factors and could extend the human lifespan.