Topological indices are numerical invariants derived from molecular graphs and play an important role in characterizing chemical compounds and predicting their properties. Among the earliest descriptors are the classical Zagreb indices introduced by Gutman and Trinajstić in 1972. A more recent development is the hyper-Zagreb index (HM), defined as HM(G)=∑_v_i v_j∈ E(G)(d_i+d_j)^2, where d_i denotes the degree of vertex v_i. In 2023, Hayat et al. posed an open problem concerning bounds on the HM index under fixed vertex-connectivity or edge-connectivity, along with the characterization of the corresponding extremal graphs. In this work, the problem is resolved by determining the extremal graphs that maximize HM index under these constraints. The investigation is further extended to several additional extremal problems, including graphs with a given number of leaves, chromatic number, and independence number. The associated extremal graphs are identified in each case. In addition, the chemical relevance of HM is examined through QSPR studies. Finally, the conclusion is presented.
High Mobility Group Box 1 (HMGB1) is a multifunctional nuclear protein which, extracellularly released, acts as a pro-inflammatory alarmin implicated in inflammatory, autoimmune and cancer-related pathologies. This review provides a detailed account on G-quadruplex (G4)-forming aptamers targeting HMGB1 and inhibiting HMGB1-induced cell migration. A SELEX-based approach allowed identifying a set G4-forming anti-HMGB1 aptamers, with L12 as the most promising one forming monomeric hybrid along with dimeric parallel G4 structures. The latter forms displayed higher affinity and activity towards HMGB1 but, upon annealing, were irreversibly converted into less active monomeric G4 structures. Covalently linked L12 dimers were designed to lock the most bioactive species, with L12d1T3 as the best candidate forming unimolecular parallel G4 structures featured by reversible folding/unfolding, marked affinity for HMGB1 and high serum resistance. These findings highlight the role of G4 structuring in anti-HMGB1 activity, showcasing covalently linked dimeric aptamers as tools for HMGB1-targeted therapy and diagnostics.
Grape pomace (GP), the solid residues remained after production of the continental and coastal Croatian red wines, has been studied by solid-state NMR and ATR-FTIR methods. After collection, drying and milling, GP samples have been analysed by IR spectroscopy and characteristic vibrational bands have been assigned. The observed differences in some functional group vibrations have been detected for continental and coastal GPs as well as for different vintages. 13C cross-polarization magic angle spinning (CP MAS) NMR experiments provided further information on chemical composition of GPs and percentages of different compounds present in the samples such as polysaccharides and phenolic compounds. 31P MAS spectra gave valuable quantitative information on the phosphorus content. The GPs from the continental varieties contain much larger portion of phosphorus compared to coastal ones, which is important for their potential use as an attractive raw material and value-added compounds for industrial applications.
A novel series of hybrid compounds N-(pyridine-2-yl) acetamide-substituted benzimidazole chalcones (9a-j) were synthesised in good yield. The structure of the compounds was confirmed by spectroscopic techniques. All the compounds were tested for their in vitro anticancer (MCF 7 cell line) and anti-Mycobacterial activity against M. tuberculosis (Vaccine strain, H37 RV strain); ATCC No-27294. Most of the compounds 9a, 9d, 9e, 9f, 9g, 9h, 9i, and 9j exhibited appreciable activity with GI50 ranging from 1.0 to 10.0 mu M against the MCF 7 cell line. On the other hand, compound 9h in the series exhibited substantial activity against the bacterial strain with a MICvalve of 12.5 mu g mL-1. Evaluation of the anticancer and anti-Mycobacterial activity showed that the compound (9h), being di-substituted with flouro group at the chalcone ring of the benzimidazole-chalcone skeleton, participate in improving the potency.
