Aß dissociation by pectolinarin may counteract against Aß-induced synaptic dysfunction and memory impairment.

Alzheimer's disease (AD) is a degenerative brain disorder characterised by various neurological symptoms, including memory impairment and mood disorders, associated with the abnormal accumulation of amyloid b(Aß) and tau proteins in the brain. There is still no definitive treatment available for AD, and the Aß antibody drugs, which are expected to be approved by the FDA, have many limitations. Therefore, there is an urgent need to develop low-molecular-weight therapeutic agents for the management of AD. In this study, we investigated whether pectolinarin, a flavonoid, regulates Aß aggregation and Aß-induced toxicity. Pectolinarin demonstrated concentration-dependent inhibition of Aß aggregation and had the ability to break down pre-formed Aß aggregates, thereby reducing their neurotoxicity. Furthermore, pectolinarin suppressed Aß aggregates-induced reduction in long-term potentiation (LTP) in the hippocampus. Oral administration of pectolinarin in experimental animals inhibited memory impairment and LTP deficits induced by Aß injection in the hippocampus. These results indicate that pectolinarin may reduce toxic Aß species and Aß-induced memory impairments and synaptic dysfunction.

2,3-Dihydrosorbicillin and chrysopanol stimulate insulin secretion in INS-1 cells.

Pancreatic ß-cell function and insulin secretion are important in antidiabetic drug development. In an effort to discover small molecules to regulate insulin secretion, an endophytic fungus, Penicillium sp. SSP-1CLG, was selected for chemical investigation. Large scale cultures of the strain followed by extraction and chromatographic analysis led to the isolation of 10 anthraquinone and alkaloid-type compounds. The isolated compounds were identified by comprehensive analysis of NMR, MS, and ECD data. The effect of compounds 1-10 on insulin secretion in INS-1 cells was investigated. 2,3-Dihydrosorbicillin (1), chrysophanol (2), and glandicolin B (10) at non-cytotoxic concentrations resulted in an increase of glucose-stimulated insulin secretion (GSIS) in rat INS-1 pancreatic ß-cells. Furthermore, we investigated the signaling pathway involved in 2,3-dihydrosorbicillin (1) and chrysophanol (2) action in the activation of peroxisome proliferator-activated receptor γ (PPARγ), pancreatic and duodenal homeobox-1 (PDX-1), insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), and Akt. Treatment of INS-1 cells with 2,3-dihydrosorbicillin (1) and chrysophanol (2) increased the expression of these proteins. Our findings indicate that 2,3-dihydrosorbicillin and chrysophanol may play roles in the regulation of insulin secretion in pancreatic ß-cells, at least in part, by targeting PPARγ and PDX-1 via the IRS-2/PI3K/Akt signaling pathway.