Abstract: This paper reports the results of a computational nanochemistry study of the chemical reactivities and bioactivity properties of two antimicrobial peptides using a CDFT-based computational peptidology (CDFT-CP) methodology, which is derived from the combination of the chemical reactivity descriptors derived from conceptual density functional theory (CDFT) and some cheminformatics tools useful in the design of therapeutic drugs. This is complemented by an examination of the bioactivity and pharmacokinetics indices of the peptides in relation to the ADMET (absorption, distribution, metabolism, excretion, and toxicity) features. These findings provide further evidence of the superiority of the MN12SX density functional in fulfilling the Janak and ionization energy theorems using an earlier proposed KID methodology for validation. This has proven to be beneficial in accurately predicting CDFT indices, which is of help in the understanding of the chemical reactivity. The computational pharmacokinetics study revealed the potential ability of both cyclopeptides as therapeutic drugs through the interaction with different target receptors. The ADMET indices confirmed this assertion through the absence of toxicity and good absorption and distribution properties.

Resumen: Este artículo reporta los resultados de un estudio de nanoquímica computacional de las reactividades químicas y propiedades de bioactividad de dos péptidos antimicrobianos usando la metodología de peptidología computacional basada en DFT conceptual (CDFT-CP, por sus siglas en inglés), la cual se ha obtenido mediante la combinación de los descriptores de reactividad química derivados de la teoría DFT conceptual (CDFT) y algunas herramientas quimioinformáticas de utilidad en el diseño de drogas terapéuticas. Esto ha sido complementado mediante un examen de los índices de bioactividad y farmacocinéticos de los péptidos en relación con sus características ADMET (absorción, distribución, metabolismo, excreción y toxicidad). Estos resultados constituyen una evidencia adicional de la superioridad del funcional de la densidad MN12SX en el cumplimiento de los teoremas de Janak y de la energía de ionización considerando la metodología KID propuesta anteriormente como validación. Este procedimiento se ha probado como benéfico en la predicción certera de los índices CFDT, lo cual es de gran ayuda en la interpretación de la reactividad química. El estudio de farmacocinética computacional ha revelado la capacidad potencial de ambos ciclopéptidos como drogas terapéuticas a través de la interacción con diferentes receptores. Los índices ADMET confirmaron este hecho a través de la ausencia de toxicidad y las buenas propiedades de absorción y distribución.

The Minnesota family of density functionals has been assessed for the calculation of the molecular structure and electronic properties of a Mg(II)-porphyrin, namely Magnesium Octaethylporphyrin (MgOEP). Several global descriptors arising from Conceptual DFT have been calculated through a ΔSCF procedure, and by means of the HOMO and LUMO frontier orbitals. On the basis of the obtained Conceptual DFT indices, a series of descriptors have been devised in order to verify the fulfillment of the "Koopmans' theorem in DFT" procedure. It is shown that the density functionals that verify this approximation with a certain degree of accuracy are only those denoted as range-separated hybrids (RSH), while the usual GGA-hybrids and the local density functionals fail completely.

Nanoparticles (NPs) of new fluoride (SrF2 and MgF2) nanocompounds were synthesized by the simple chemical method of precipitation in ethanol. Synthesis of the strontium fluoride (SrF2)-magnesium oxide (MgO) nanocomposite was achieved through the ultrasonic method. These prepared nanopowders were characterized through Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Powder X-ray Diffraction (PXRD) and Scanning Electron Microscopy (SEM). FT-IR confirmed the purity of the synthesized fluoride NPs by evaluation of the vibrations, and UV-Visible showed the intense absorption peaks of NPs. PXRD analysis indicated the average of particle size, and SEM demonstrated a nearly spherical morphology of the NPs. The antibacterical properties of the nanopowders on Staphylococcus Aureus, Bacillus Subtilis and E. Aklay bacteria were studied, with the strongest effect by the magnesium fluoride (MgF2) NPs and the SrF2-MgO nanocomposite.

The Minnesota family of density functionals (M06, M06L, M06-2X and M06-HF) has been used to calculate the UV-Vis spectra of the thioindigo molecule in solvents of different polarities using time-dependent density functional theory (TD-DFT) and the polarized continuum model (PCM). The maximum absorbance wavelengths predicted for each functional were compared with the known experimental results.

Los funcionales de la densidad de la familia Minnesota (M06, M06L, M06-2X y M06-HF) han sido considerados para calcular el espectro UV-Vis, de la molécula tioíndigo en solventes de diferentes polaridades, usando la teoría de funcionales de la densidad dependiente del tiempo (TD-DFT) y el modelo del continuo polarizado (PCM). Las longitudes de onda de máxima absorción, predicha para cada funcional fueron comparadas con resultados experimentales conocidos.