Quantum chemical, experimental exploration of biological activity and inhibitory potential of new cytotoxic kochiosides fromKochia prostrata(L.) Schrad

New cytotoxic steroidal glycoside of methanol extract from Kochia prostrata ([Formula: see text]) Schrad was investigated in this study. Bio-guided isolation from ethylacetate fraction of whole plant afforded steroidal glycosides named as 5-ene-dimethylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 1A1), 5-ene-methylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 2A1) and 4-ene-dimethylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 3A1). Their structures were assigned by physical and spectroscopic methods. Kochiosides 1A1–3A1showed inhibitory potential against brine shrimp lethality bioassay with etoposide standard drug. The new steroidal glycoside kochiosides 1A1–3A1showed inhibition values of 8.3201, 8.8205 and 8.2310[Formula: see text][Formula: see text]g/mL, respectively with [Formula: see text] compared to standard etoposide [Formula: see text] (7.4625[Formula: see text][Formula: see text]g/mL) drug. Moreover, six new derivatives were designed by substituting the –NH2and –OCH3at R1, R2 and R3 positions in the isolated compounds. Herein, various molecular descriptors, frontier molecular orbitals (FMO), electron affinity, ionization potential and molecular electrostatic potential (MEP) were carried out to understand the active sites and biological active nature of the new cytotoxic steroidal glycoside kochiosides. The effect of electron donating groups (–NH2and –OCH3) was also investigated on the structural parameters and electronic properties in gas and solvent (DMSO) phases. The energy gap, MEP and reactivity descriptors values demonstrate that the kochioside 3A1retains good reactivity, which is in good agreement with current experimental studies.

Benzimidazole derivatives as anticancer drugs: A theoretical investigation

In this study the anticancer properties of a series of benzimidazole drugs 1–9 and their interactions with DNA base pairs were investigated. The obtained theoretical results for anticancer activity of synthesized drugs 1–5 were compared to corresponding published experimental results. Based on theoretical and published experimental anticancer scales, drugs 2 and 4 have higher anticancer activity among drugs 1–5. Obtained results reveal that interactions of studied drugs with DNA base pairs are energetically favorable and solvent and electric field (EF) increase the binding energies in comparison to gas phase. The binding energies of drugs 2, 5 and 4 with DNA base pairs are more negative than corresponding values for drug 1. We propose the novel drugs 6–9 to synthesize with higher anticancer activity. Results show that binding energies of novel drugs 6–9 were more negative than drugs 1–5. Finally, results show that chemical potential, electrophilicity and global hardness can be considered as admissible theoretical anticancer indexes for studied benzimidazole drugs 1–9.

3D-QSAR AND DOCKING STUDIES OF NOVEL QUINAZOLINE ANALOGUES AS ORAL INHIBITORS TOWARDS AP-1 AND NF-κB

Three-dimensional quantitative structure-activity relationship (3D-QSAR) and Docking studies of novel quinazoline analogues, which are oral potential inhibitors towards the activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB), have been carried out. The 3D-QSAR study based on the comparative molecular field analysis (CoMFA) shows the established model having a significant statistical quality and excellent predictive ability, in which the correlation coefficient R is 0.972 and cross-validation coefficient q2 is 0.619. The Docking results also show a considerable correlation (or trend) between the energy scores and the corresponding experimental values for these compounds at some sites. Meanwhile, it is very interesting to find the binding sites just fall on the joint regions between AP-1 (or NF-κB) and DNA. It may be the reason that the quinazoline analogues have inhibition function because their existence on these joint regions can effectively prevent free AP-1 and NF-κB from binding to DNA. Based on the established 3D-QSAR and Docking analyses, six new compounds of quinazoline analogues with higher inhibitory activities were theoretically designed and presented. The above results can offer some valuable theoretical references for the pharmaceutical molecular design as well as the action mechanism analysis.