Background: Inhibiting α-glucosidase and α-amylase is a well-established strategy for managing postprandial hyperglycemia in type 2 diabetes mellitus. However, the adverse effects of current α-glucosidase inhibitors (α-GIs) underscore the need for safer alternatives. Methods: This study introduces an efficient, metal-free, and environmentally friendly protocol for the selective, high-yield synthesis of 1,2-disubstituted benzimidazoles. The reaction between o-phenylenediamine and various aromatic aldehydes proceeds smoothly in water at room temperature, using cost-effective and eco-friendly catalysts such as acetylsalicylic acid (ASA) or salicylic acid (SA). The methodology exhibits broad versatility, enabled by the use of different o-phenylenediamines and a wide range of aromatic and heteroaromatic aldehydes. Results: Selected compounds were assessed for their inhibitory activity against α-glucosidase and α-amylase. While all exhibited low α-amylase inhibition, several showed significant α-glucosidase inhibition, with compounds 8s (IC₅₀ = 0.39 ± 0.04 μM), 8k (IC₅₀ = 7.4 ± 1.6 μM) and 8r (IC₅₀ = 13.8 ± 2.7 μM) emerging as the most promising candidates. Notably, none of these compounds affected Caco-2 cell viability at concentrations up to 30 μM. Additionally, compounds 8r and 8s exhibited antioxidant properties, which may be relevant in counteracting the excessive production of free radicals associated with diabetes. Preliminary molecular docking and 500 ns molecular dynamics (MD) simulations were carried out on compounds 3k, 8i, 8k, and 8p–8s to support and interpret the experimental biological findings qualitatively.

The spread of Human Immunodeficiency Virus (HIV) still represents a global public health issue of major concern, and would benefit from unveiling unique viral features as targets for drug design. In this respect, HIV-1 integrase (IN), due to the absence of homologs in human cells, is a popular target for the synthesis of novel selective compounds. Moreover, as drug-resistant viral strains are rapidly evolving, the development of novel allosteric inhibitors is acutely required. Recently, we have observed that Kuwanon-L, quinazolinones and thienopyrimidinones containing at least one polyphenol unit, effectively inhibited HIV-1 IN activity. Thus, in the present research, novel dihydroxyphenyl-based thienopyrimidinone derivatives were investigated for their LEDGF/p75-dependent IN inhibitory activity. Our findings indicated a close correlation between the position of the OH group on the phenyl moiety and IN inhibitory activity of these compounds. As catechol may be involved in cytotoxicity, its replacement by other aromatic scaffolds was also exploited. As a result, compounds 21–23, 25 and 26 with enhanced IN inhibitory activity provided good lead candidates, with 25 being the most selective for IN. Lastly, UV spectrometric experiments suggested a plausible allosteric mode of action, as none of the thienopirimidinones showed Mg²⁺ chelation properties otherwise typical of IN strand transfer inhibitors (INSTIs).

A promising novel class of 2-(trihydroxyphenyl)thieno[2,3-d]pyrimidin-4(3H)-ones as HIV-1 integrase (IN) allosteric inhibitors is reported. All compounds were considerably more effective than the control compound LEDGIN-6, showing an inhibitory activity in the low micromolar range in both the HIV-1 integrase LEDGF/p75-dependent and independent activity assays. Selected compounds 6, 9, 10, and 12 were also able to affect the exchange of the HIV-1 IN-IN subunit and the interaction between IN and LEDGF/p75. Differently from LEDGINs, small-molecule inhibitors were able to interact with the IN binding domain (IBD) of Lens-Epithelium-derived Growth Factor/p75 (LEDGF/p75) and HIV-1 IN, and none of these compounds was able to induce multimerization, suggesting a different mechanism of action. In silico experiments carried out on compounds 6 and 10 suggest that a region adjacent to the sucrose binding site (SBS), together with a second nearby cavity, may represent relevant allosteric regions for their interaction with IN. In vitro experiments performed in the presence and absence of sucrose on selected IN mutants are qualitatively consistent with this model, although further structural and biophysical studies will be required to define the exact binding mode.