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Ammi majus, a well-established member of the Umbelliferae (Apiaceae) family, is endogenous to Egypt. The main parts of this plant that are used are the fruits, which contain coumarins and flavonoids as major active constituents. The roots are usually considered by-products that are discarded and not fed to cattle because of coumarins’ potential toxicity. The goal of this study was to ensure the sustainability of the plant, investigate the active metabolites present in the roots using UPLC/MS-MS, isolate and elucidate the major coumarin Xanthotoxin, and predict its oral bioavailability and its potential biological impact on tongue papillae. The results revealed coumarins as the dominant chemical class in a positive acquisition mode, with bergaptol-O-hexoside 5%, Xanthotoxin 5.5%, and isoarnoittinin 6% being the major compounds. However, phenolics ruled in the negative mode, with p-coumaroyl tartaric acid 7%, 3,7-dimethyl quercetin 6%, and hesperidin 5% being the most prominent metabolites. Fractionation and purification of the chloroform fraction yielded Xanthotoxin as one of the main compounds, which appeared as white needle crystals (20 mg). ADME studies for oral bioavailability were performed to predict the potential properties of the compound if used orally. It was noted that it followed Lipinski’s rule of five, had just one parameter outside of the pink area in the radar plot, and was detected inside the threshold area using the boiled egg approach. In vivo, histopathological studies performed on rats showed a notable decrease in the tongue’s keratin thickness from an average of 51.1 µm to 9.1 µm and an average of 51.8 µm to 9.8 µm in fungiform and filiform cells, respectively. The results indicated that although Xanthotoxin is a well-known medical agent with several potential therapeutic activities in oral therapy, it may cause a destructive effect on the structure of the specialized mucosa of the tongue. Full article

We report synthesis of a novel 1,2,3,4-tetrahydroquinazoline derivative, named 2-(6,8-dibromo-3-(4-hydroxycyclohexyl)-1,2,3,4-tetrahydroquinazolin-2-yl)phenol (1), which was obtained from the hydrochloride of 4-((2-amino-3,5-dibromobenzyl)amino)cyclohexan-1-ol (ambroxol hydrochloride) and salicylaldehyde in EtOH. The resulting compound was produced in the form of colorless crystals of the composition 1∙0.5EtOH. The formation of the single product was confirmed by the IR and ¹H spectroscopy, single-crystal and powder X-ray diffraction, and elemental analysis. The molecule of 1 contains a chiral tertiary carbon of the 1,2,3,4-tetrahydropyrimidine fragment and the crystal structure of 1∙0.5EtOH is a racemate. Optical properties of 1∙0.5EtOH were revealed by UV-vis spectroscopy in MeOH and it was established that the compound absorbs exclusively in the UV region up to about 350 nm. 1∙0.5EtOH in MeOH exhibits dual emission and the emission spectra contains bands at about 340 and 446 nm upon excitation at 300 and 360 nm, respectively. The DFT calculations were performed to verify the structure as well as electronic and optical properties of 1. ADMET properties of the R-isomer of 1 were evaluated using the SwissADME, BOILED-Egg, and ProTox-II tools. As evidenced from the blue dot position in the BOILED-Egg plot, both human blood–brain barrier penetration and gastrointestinal absorption properties are positive with the positive PGP effect on the molecule. Molecular docking was applied to examine the influence of the structures of both R-isomer and S-isomer of 1 on a series of the SARS-CoV-2 proteins. According to the docking analysis results, both isomers of 1 were found to be active against all the applied SARS-CoV-2 proteins with the best binding affinities with Papain-like protease (PLpro) and nonstructural protein 3 (Nsp3_range 207–379-AMP). Ligand efficiency scores for both isomers of 1 inside the binding sites of the applied proteins were also revealed and compared with the initial ligands. Molecular dynamics simulations were also applied to evaluate the stability of complexes of both isomers with Papain-like protease (PLpro) and nonstructural protein 3 (Nsp3_range 207–379-AMP). The complex of the S-isomer with Papain-like protease (PLpro) was found to be highly unstable, while the other complexes are stable. Full article

The use of computer-aided drug design (CADD) for the identification of lead compounds in radiotracer development is steadily increasing. Traditional CADD methods, such as structure-based and ligand-based virtual screening and optimization, have been successfully utilized in many drug discovery programs and are highlighted throughout this review. First, we discuss the use of virtual screening for hit identification at the beginning of drug discovery programs. This is followed by an analysis of how the hits derived from virtual screening can be filtered and culled to highly probable candidates to test in in vitro assays. We then illustrate how CADD can be used to optimize the potency of experimentally validated hit compounds from virtual screening for use in positron emission tomography (PET). Finally, we conclude with a survey of the newest techniques in CADD employing machine learning (ML). Full article