Development of Activity Rules and Chemical Fragment Design for In Silico Discovery of AChE and BACE1 Dual Inhibitors against Alzheimer's Disease.

Multi-target drug development has become an attractive strategy in the discovery of drugs to treat of Alzheimer's disease (AzD). In this study, for the first time, a rule-based machine learning (ML) approach with classification trees (CT) was applied for the rational design of novel dual-target acetylcholinesterase (AChE) and ß-site amyloid-protein precursor cleaving enzyme 1 (BACE1) inhibitors. Updated data from 3524 compounds with AChE and BACE1 measurements were curated from the ChEMBL database. The best global accuracies of training/external validation for AChE and BACE1 were 0.85/0.80 and 0.83/0.81, respectively. The rules were then applied to screen dual inhibitors from the original databases. Based on the best rules obtained from each classification tree, a set of potential AChE and BACE1 inhibitors were identified, and active fragments were extracted using Murcko-type decomposition analysis. More than 250 novel inhibitors were designed in silico based on active fragments and predicted AChE and BACE1 inhibitory activity using consensus QSAR models and docking validations. The rule-based and ML approach applied in this study may be useful for the in silico design and screening of new AChE and BACE1 dual inhibitors against AzD.

Efficacy of marine bioactive compound fucoidan for bone regeneration and implant fixation in sheep.

The need for a substitute for allograft and autograft is rising as bone graft surgeries exceed available supplies. We investigated the efficacy of the low-molecular weight marine bioactive compound fucoidan (FUC) on bone regeneration and implant fixation in seven female sheep, as FUC has shown great promise as a bone substitute. Titanium implants were inserted bilaterally in the distal femurs to test three hydroxyapatite/fucoidan (HA/FUC) groups and compared to allograft. The HA was coated with either 500 or 1500 µg of FUC, obtained by microwave-assisted chemical extraction, or 500 µg of FUC obtained by an enzyme-assisted extraction method. The concentric 2-mm gap around the implant was filled with either one of the HA/FUCs or allograft from the donor sheep. After 12 weeks, implant-bone blocks were harvested and divided into three parts for mechanical push-out testing, immunohistochemistry, and micro-CT and histomorphometry. Pronounced bone formations were observed by micro-CT and histomorphometry in all groups, but higher bone volume fractions were seen in the allograft group compared to the three HA/FUC groups. The trabecular thickness, trabecular separation, and architectural anisotropy were all significantly higher in the allograft group compared to the three HA/FUC groups. In conclusion, adequate bone formation was observed in all groups, although the bone formation was significantly greater in the allograft group. Also, no significant differences existed in the shear mechanical properties between groups, suggesting that the combination of HA and FUC can achieve a similar fixation strength to allograft in this model.

Effects of a Newly Developed Enzyme-Assisted Extraction Method on the Biological Activities of Fucoidans in Ocular Cells.

Fucoidans from brown seaweeds are promising substances as potential drugs against age-related macular degeneration (AMD). The heterogeneity of fucoidans requires intensive research in order to find suitable species and extraction methods. Ten different fucoidan samples extracted enzymatically from Laminaria digitata (LD), Saccharina latissima (SL) and Fucus distichus subsp. evanescens (FE) were tested for toxicity, oxidative stress protection and VEGF (vascular endothelial growth factor) inhibition. For this study crude fucoidans were extracted from seaweeds using different enzymes and SL fucoidans were further separated into three fractions (SL_F1-F3) by ion-exchange chromatography (IEX). Fucoidan composition was analyzed by high performance anion exchange chromatography (HPAEC) after acid hydrolysis. The crude extracts contained alginate, while two of the fractionated SL fucoidans SL_F2 and SL_F3 were highly pure. Cell viability was assessed with an 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay in OMM-1 and ARPE-19. Protective effects were investigated after 24 h of stress insult in OMM-1 and ARPE-19. Secreted VEGF was analyzed via ELISA (enzyme-linked immunosorbent assay) in ARPE-19 cells. Fucoidans showed no toxic effects. In OMM-1 SL_F2 and several FE fucoidans were protective. LD_SiAT2 (Cellic®CTec2 + Sigma-Aldrich alginate lyase), FE_SiAT3 (Cellic® CTec3 + Sigma-Aldrich alginate lyase), SL_F2 and SL_F3 inhibited VEGF with the latter two as the most effective. We could show that enzyme treated fucoidans in general and the fractionated SL fucoidans SL_F2 and SL_F3 are very promising for beneficial AMD relevant biological activities.

Immediate-released pelletized solid dispersion containing fenofibrate: Formulation, in vitro characterization, and bioequivalence studies in experimental beagle dogs.

There have been many strategies to increase solubility, dissolution rates, and oral bioavailability of fenofibrate such as micronization, nanonization, solid dispersion, and emulsion so far. To our knowledge, only first three technologies have been applied in producing marketed products, and no combination of solid dispersion and pellet has been found even in laboratory-based reports. Therefore, the aim of this study was to develop novel solid dispersion-based pellets via an one-step process directly from fenofibrate powder using layering method. Developed fenofibrate pellets were in vitro characterized on size distribution, dissolution rates, sensory evaluation and stability. In addition, the transformation from crystalline fenofibrate to amorphous fenofibrate, and intermolecular interactions of fenofibrate in solid dispersion were confirmed using physico-chemical methods. The dissolution rate of pellets containing fenofibrate was significantly higher than that of the reference, Lipanthyl® 160 mg tablets at early stage, satisfying the criteria in USP 38. The pellets, then, were packed in hard capsules for bioequivalence studies in experimental beagle dogs using a validated HPLC assay. Final findings of the present study should be beneficial for further development of new fenofibrate formulations containing solid dispersion-based pellets which were bioequivalent to Lipanthyl® 160 mg tablets.