Favipiravir: Insight into the Crystal Structure, Hirshfeld Surface Analysis and Computational Study

In this work we report structural and computational studies of favipiravir, which is now used as a drug for COVID-19 treatment. The molecule is completely flat and stabilized by an intramolecular O–H···O hydrogen bond, yielding a six-membered pseudo-aromatic ring. The aromaticity index of this pseudo-aromatic ring was found to be 0.748, while the same indix for the pyrazine ring in favipiravir was found to be 0.954. The crystal packing of favipiravir is mainly constructed through intermolecular N–H···O, N–H···N and C–H···O hydrogen bonds, yielding a 3D supramolecular framework with a zst topology defined by the point symbol of (65·8). The crystal structure of favipiravir is further stabilized by weak C–F···F–C intermolecular type II dihalogen interactions, yielding a 1D supramolecular polymeric chain. More than 80% of the total Hirshfeld surface area for favipiravir is occupied by H···H/C/N/O/F and C···N/O contacts. Energy frameworks have been calculated to additionally analyze the overall crystal packing. It was established that the structure of favipiravir is mainly characterized by the dispersion energy framework followed by the less significant electrostatic energy framework contribution. Finally, by using density functional theory (DFT) calculations and the quantum theory of atoms in molecules, we have assigned the interaction energy of each hydrogen bond, which can be helpful to develop scoring functions to be used in force fields/docking calculations. © 2021, Iranian Chemical Society.A. Frontera thanks the MICIU/AEI of Spain (project CTQ2017-85821-R FEDER funds) for financial support

Time- and Dose-Dependent Induction of HSP70 in Lemna minor Exposed to Different Environmental Stressors

The objective of this study was to examine the influence of different stressors, including cadmium (heavy metal), anthracene (polycyclic aromatic hydrocarbon—PAH) and chloridazon (herbicide), on population growth and biosynthesis of cytoplasmic HSP70 in Lemna minor (duckweed) in short (4 h)- and long (7 days)-term tests. A heat shock response was confirmed in Lemna exposed to high temperature: 35, 37.5, 40, or 42.5°C in short-term (4 h) treatments. The chemicals tested stimulated the biosynthesis of the cytoplasmic HSP70 protein in a concentration-dependent way (0.5–5 μM), higher in fronds exposed to lower doses of stressors. Additionally, production of HSP70 was greater after 4 h of incubation than after 7 days. The results suggest that HSP70 could be applied as a non-specific and sensitive detector of stress induced by different chemicals at concentrations below those that produce the type of response observed in classical cytotoxicity tests, such as growth inhibition

The effect of Aldicarb on the amount of chlorophyll and protein of Cladophora glomerata (Chlorophyceae) [Aldikarp'in cladophora glomerata 'da (Chlorophyceae) clorofil ve protein miktarina etkileri]

The effects of Aldicarb on the amounts of chlorophyll, protein and carbohydrates are investigated in Cladophora glomerata. Cladophora glomerata was subjected to Aldicarb concentrations of 1, 2.5, 5, 10, 25, 50, 75, and 100 ppm. The amunts of chlorophyll, protein and carbohydrate, were, however, singificantly reduced at high concentrations. Our microscopic investigations show that the cellular integrity began to be affected at the concentrations higher than 10 ppm

Sorption of cadmium and their effects on growth, protein contents, and photosynthetic pigment composition of veronica anagallis-aquatica L. and Ranunculus aquatilis L.

PubMedID: 10960136[No abstract available