Improving the solubility of pseudo-hydrophobic Alzheimer's Disease medicinal chemicals through co-crystal formulation

Natural products are ligands and potential inhibitors of Alzheimer's disease (AD) tau. Dihydromyricetin (DHM) is a CNS active natural product. Despite having signature polyphenolic character, DHM is ostensibly hydrophobic owing to intermolecular hydrogen bonds that shield hydrophilic phenols. Our research shows DHM becomes ionized at near-neutral pH allowing formulation of salts with transformed solubility. The MicroED co-crystal structure with trolamine reveals DHM salts as metastable solids with unlocked hydrogen bonding and a thermodynamic bent to solubilize in water. All salt formulations show better inhibitory activity against AD tau than the non-salt form, with efficacies correlating to enhanced solubilities. These results underscore the role of structural chemistry in guiding selection of solubilizing agents for chemical formulation. We propose DHM salts are appropriate formulations for research as dietary supplements to promote healthy aging by combating protein misfolding. Additionally, DHM is a suitable lead for medicinal chemistry and possible development of CNS pharmaceuticals.

A hitherto undescribed benign mesenchymal polyp of the gallbladder: edematous angiomyolipoma-like polyp

We report a case of two peculiar gallbladder polyps in a sixty-four year old male who presented with symptomatic cholelithiasis. Cholecystectomy was performed, which revealed two polyps measuring 0.6 cm and 1.9 cm, located in the body of the gallbladder. Microscopic examination of the polyps showed composite mesenchymal lesions with vascular proliferation of small-to-medium sized arterioles, myoid stroma, and lipomatous periphery. The myoid component was characterized by wisps of bland smooth muscle fibers loosely separated by proteinaceous and focally myxoid matrix. The surface of the polyps was lined by a single layer of bland epithelial cells. The unique histomorphologic features differentiate the lesions from other known mesenchymal polyps of the gallbladder. We propose the name "edematous angiomyolipoma-like polyp" for these rare lesions given their histomorphologic similarity to angiomyolipoma. (Acta gastroenterol. belg., 2016, 79, 371-374).

KpnBI is the prototype of a new family (IE) of bacterial type I restriction-modification system

KpnBI is a restriction-modification (R-M) system recognized in the GM236 strain of Klebsiella pneumoniae. Here, the KpnBI modification genes were cloned into a plasmid using a modification expression screening method. The modification genes that consist of both hsdM (2631 bp) and hsdS (1344 bp) genes were identified on an 8.2 kb EcoRI chromosomal fragment. These two genes overlap by one base and share the same promoter located upstream of the hsdM gene. Using recently developed plasmid R-M tests and a computer program RM Search, the DNA recognition sequence for the KpnBI enzymes was identified as a new 8 nt sequence containing one degenerate base with a 6 nt spacer, CAAANNNNNNRTCA. From Dam methylation and HindIII sensitivity tests, the methylation loci were predicted to be the italicized third adenine in the 5' specific region and the adenine opposite the italicized thymine in the 3' specific region. Combined with previous sequence data for hsdR, we concluded that the KpnBI system is a typical type I R-M system. The deduced amino acid sequences of the three subunits of the KpnBI system show only limited homologies (25 to 33% identity) at best, to the four previously categorized type I families (IA, IB, IC, and ID). Furthermore, their identity scores to other uncharacterized putative genome type I sequences were 53% at maximum. Therefore, we propose that KpnBI is the prototype of a new 'type IE' family.