Berberine is well known for its ability to reduce the blood glucose level, but its high effective dose and poor bioavailability limits its use. In this work we synthesized a new derivative of berberine, 9-(hexylamino)-2,3-methylenedioxy-10-methoxyprotoberberine chloride (SHE-196), and analyzed the profile of its hypoglycemic effects. Biological tests have shown that the substance has a very pronounced hypoglycemic activity due to increased insulin sensitivity after single and multiple dosing. In obese type 2 diabetes mellitus (T2DM) mice, it was characterized by improved glucose tolerance, decreased fasting insulin levels and sensitivity, decreased total body weight and interscapular fat mass, and increased interscapular brown fat activity. All these effects were also confirmed histologically, where a decrease in fatty degeneration of the liver, an improvement in the condition of the islets of Langerhans and a decrease in the size of fat droplets in brown adipose tissue were found. Our results indicate that 9-(hexylamino)-2,3-methylenedioxy-10-methoxyprotoberberine chloride could be the first in a new series of therapeutic agents for the treatment of diabetes mellitus.

Although the COVID-19 pandemic caused by SARS-CoV-2 viruses is officially over, the search for new effective agents with activity against a wide range of coronaviruses is still an important task for medical chemists and virologists. We synthesized a series of thiazolo-thiophenes based on (+)- and (−)-usnic acid and studied their ability to inhibit the main protease of SARS-CoV-2. Substances containing unsubstituted thiophene groups or methyl- or bromo-substituted thiophene moieties showed moderate activity. Derivatives containing nitro substituents in the thiophene heterocycle—just as pure (+)- and (−)-usnic acids—showed no anti-3CL^pro activity. Kinetic parameters of the most active compound, (+)-3e, were investigated, and molecular modeling of the possible interaction of the new thiazolo-thiophenes with the active site of the main protease was carried out. We evaluated the binding energies of the ligand and protein in a ligand–protein complex. Active compound (+)-3e was found to bind with minimum free energy; the binding of inactive compound (+)-3g is characterized by higher values of minimum free energy; the positioning of pure (+)-usnic acid proved to be unstable and is accompanied by the formation of intermolecular contacts with many amino acids of the catalytic binding site. Thus, the molecular dynamics results were consistent with the experimental data. In an in vitro antiviral assay against six strains (Wuhan, Delta, and four Omicron sublineages) of SARS-CoV-2, (+)-3e demonstrated pronounced antiviral activity against all the strains.

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide. Several classes of hypoglycemic drugs are used to treat it, but various side effects limit their clinical use. Consequently, the search for new anti-diabetic agents remains an urgent task for modern pharmacology. In this investigation, we examined the hypoglycemic effects of bornyl-containing benzyloxyphenylpropanoic acid derivatives (QS-528 and QS-619) in a diet-induced model of T2DM. Animals were given the tested compounds per os at a dose of 30 mg/kg for 4 weeks. At the end of the experiment, compound QS-619 demonstrated a hypoglycemic effect, while QS-528 showed hepatoprotection. In addition, we performed a number of in vitro and in vivo experiments to study the presumed mechanism of action of the tested agents. Compound QS-619 was determined to activate the free fatty acid receptor-1 (FFAR1) similarly to the reference agonist GW9508 and its structural analogue QS-528. Both agents also increased insulin and glucose-dependent insulinotropic polypeptide concentrations in CD-1 mice. Our results indicate that QS-619 and QS-528 are probably full FFAR1 agonists.

Free fatty acid receptor-1 (FFAR1) is one of the possible therapeutic targets in the search for new hepatoprotective drugs. FFAR1 agonists were found to have hypolipidemic, antifibrotic, anti-inflammatory, antiproliferative and antioxidant effects in addition to hypoglycemic action. In this work, we conducted a study of the hepatoprotective effect of the compound QS-528 (previously discovered as an agonist of FFAR1) at doses of 60, 90, 120 and 150 mg/kg on carbon tetrachloride (CCl₄)-induced liver injury. At the end of the experiment, a biochemical blood assay demonstrated that the introduction of QS-528 dose-dependently reduces the levels of liver enzymes (AST, ALT and ALKP). Histological and morphometric studies of animals’ livers treated with QS-528 at doses of 120 and 150 mg/kg showed a decrease in degenerative/necrotic changes in hepatocytes and an increase in the regenerative activity of the liver. In addition, no toxicity at a single oral dose of 1000 mg/kg and an increase in HepG2 cell viability in vitro were found. Thus, the compound QS-528 was found to exhibit a hepatoprotective effect against CCl₄-induced toxic liver damage.

Dual PPARα/γ agonists can normalize both glucose and lipid metabolism in patients with type 2 diabetes mellitus. The development of such drugs faced the detection of various toxic effects in phase III clinical trials. However, two drugs of this class managed to pass all stages of clinical trials, which makes the search for new dual PPARα/γ agonists promising. In the present study, a series of dihydrobetulonic acid amides differing in the length of the amino-alcohol linker and incorporating a pharmacophore fragment of (S)-2-ethoxy-3-phenylpropanoic acid were synthesized. The in vitro study showed that the length of the aminoalcohol linker dramatically affects the level of activation of PPAR-α and γ receptors. The synthesized compounds were tested for their ability to improve glycemic control and to counter lipid abnormalities in C57Bl/6 Ay/a mice at a dose of 30 mg/kg. Of all the compounds tested, the dihydrobetulonic acid derivative with an aminoethanol linker (15a) had the most pronounced effect in improving insulin sensitivity and glucose tolerance, and in reducing blood triglyceride levels. In addition, 15a dramatically counteracted the pathological changes in the liver, pancreas, kidney, and brown fat tissue that are characteristic of type 2 diabetes.

Several novel 9-N-n-alkyl derivatives of berberine (C5, C7, C10, C12) were synthesized. They were analyzed in vitro and in vivo for their hypoglycemic activity. In vitro studies showed that the derivatives with shorter alkyl substitutes at concentrations ranging from 2.5 to 10 μM were able to stimulate glucose consumption by HepG2 cells more prominently than the derivatives with longer substitutes (C10 and C12). All compounds demonstrated a better effect compared to berberine. Their impact on cells’ viability also depended on the alkyl substitutes length, but in this case, C10 and C12 derivatives demonstrated the best results. A similar correlation was also found in the OGTT, where the C5 derivative demonstrated a pronounced hypoglycemic effect at a dose of 15 mg/kg and C12 was less effective. This compound was further investigated in C57BL/6^Ay mice for four weeks and was administered at a dose of 15 mg/kg. Pronounced effect of C12 on carbohydrate metabolism in mice was discovered: there was a decrease in fasting glucose levels and an increase in glucose tolerance in OGTT on the 14th and 28th days of the experiment. However, at the end of the experiment, signs of hepatosis exacerbation and an increase in the content of hepatic aminotransferases in blood were found.