Current Medicinal Chemistry - Volume 32, Issue 9, 2025

Metformin, a biguanide on the WHO’s list of essential medicines has a long history of 50 years or more in treating hyperglycemia, and its therapeutic saga continues beyond diabetes treatment. Glucoregulatory actions are central to the physiological effects of metformin; surprisingly, the precise mechanism with which metformin regulates glucose metabolism is not thoroughly understood yet.

The main aim of this review is to explore the recent implications of metformin in hepatic gluconeogenesis, AMPKs, and SHIP2 and subsequently to elucidate the metformin action across intestine and gut microbiota. We have searched PubMed, Google scholar, Medline, eMedicine, National Library of Medicine (NLM), clinicaltrials.gov (registry), and ReleMed for the implications of metformin with its updated role in AMPKs, SHIP2, and hepatic gluoconeogenesis, and gut microbiota. In this review, we have described the efficacy of metformin as a drug repurposing strategy in modulating the role of AMPKs lysosomal-AMPKs, and also, the controversies associated with metformin.

Research suggests that biguanide exhibits hormetic effects depending on the concentrations used (micromolar to millimolar). The primary mechanism attributed to metformin action is the inhibition of mitochondrial complex I, and subsequent reduction of cellular energy state, as observed with increased AMP or ADP ratio, thereby metformin can also activate the cellular energy sensor AMPK to inhibit hepatic gluconeogenesis. However, new mechanistic models have been proposed lately to explain the pleiotropic actions of metformin; at low dose, metformin can activate lysosomal-AMPK via the AXIN-LKB1 pathway. Conversely, in an AMPK-independent mechanism, metformin-induced elevation of AMP suppresses adenylate cyclase and glucagon-activated cAMP production to inhibit hepatic glucose output by glucagon. Metformin inhibits mitochondrial glycerophosphate dehydrogenase; mGPDH, and increases the cytosolic NADH/NAD⁺, affecting the availability of lactate and glycerol for gluconeogenesis. Metformin can inhibit Src homology 2 domain-containing inositol 5-phosphatase 2; SHIP2 to increase the insulin sensitivity and glucose uptake by peripheral tissues. In addition, new exciting mechanisms suggest the role of metformin in promoting beneficial gut microbiome and gut health. Metformin regulates duodenal AMPK activation, incretin harmone secretion and bile acid homeostasis to improve intestinal glucose absorption and utilization.

The proper understanding of the key regulators of metformin actions is of utmost importance to enhance its pleotropic benefits on diabetes and beyond.

The relationship between the cellular pro-inflammatory response and intracellular lipid accumulation in atherosclerosis is not sufficiently studied. Transcriptomic analysis is one way to establish such a relationship. Previously, we identified 10 potential key genes (IL-15, CXCL8, PERK, IL-7, IL-7R, DUSP1, TIGIT, F2RL1, TSPYL2, and ANXA1) involved in cholesterol accumulation in macrophages. It should be noted that all these genes do not directly participate in cholesterol metabolism, but encode molecules related to inflammation.

In this study, we conducted a knock-down of the 10 identified key genes using siRNA to determine their possible role in cholesterol accumulation in macrophages. To assess cholesterol accumulation, human monocyte-derived macrophages (MDM) were incubated with atherogenic LDL from patients with atherosclerosis. Cholesterol content was assessed by the enzymatic method. Differentially expressed genes were identified with DESeq2 analysis. Master genes were determined by the functional analysis.

We found that only 5 out of 10 genes (IL-15, PERK, IL-7, IL-7R, ANXA1) can affect intracellular lipid accumulation. Knock-down of the IL-15, PERK, and ANXA1 genes prevented lipid accumulation, while knock-down of the IL-7 and IL-7R genes led to increased intracellular lipid accumulation during incubation of MDM with atherogenic LDL. Seventeen overexpressed genes and 189 underexpressed genes were obtained in the DGE analysis, which allowed us to discover 20 upregulated and 86 downregulated metabolic pathways, a number of which are associated with chronic inflammation and insulin signaling. We also elucidated 13 master regulators of cholesterol accumulation that are immune response-associated genes.

Thus, it was discovered that 5 inflammation-related master regulators may be involved in lipid accumulation in macrophages. Therefore, the pro-inflammatory response of macrophages may trigger foam cell formation rather than the other way around, where intracellular lipid accumulation causes an inflammatory response, as previously assumed.

Triple-negative breast cancer (TNBC), an aggressive type of breast cancer, remains difficult to treat. Isoliquiritigenin (ISL) is a bioactive compound that is insoluble in water and exhibits significant anti-TNBC activity.

We previously prepared oral aqueous ISL@ZLH NPs; however, they were less stable in a freezing environment. Hence, the present study aimed to improve the stability of ISL@ZLH NPs using cryoprotectants that can withstand long storage times and are effective in TNBC treatment by creating an efficient oral drug delivery system. Freeze-dried ISL@ZLH NP powder was prepared by solvent evaporation, followed by the addition of trehalose and sucrose. The freeze-dried ISL@ZLH NP pow was optimized and characterized. The anti-TNBC efficacy and pharmacokinetics of the ISL@ZLH NP-pow were examined in plasma and organs, compared with those of aqueous ISL@ZLH NPs.

The ideal particle size of the ISL@ZLH NP pow was 118 nm, which was not filtered out by the glomerulus and allowed the drug to be delivered to the lesions more effectively. Cellular uptake and biodistribution of the ISL@ZLH NP-pow in vivo and in vitro showed prolonged storage in the organs. In addition, cryopreserved ISL@ZLH NP-treated tumors showed significant anti-proliferative and anti-migratory effects through the downregulation of the PI3K-Akt-mToR and MMP2/9 signaling pathways.

These results suggest that oral ingestion of cryopreserved ISL@ZLH NP has the potential for long-term storage and can be employed as a clinical therapeutic approach to treat TNBC.

In this study, a neoteric and expedient oxidation method is applied for a variety of Hantzsch 1,4-dihydropyridine derivatives such as 1,4-dihydro-2,6-dimethyl-3,5-diacetylpyridine, 3,5-bis-hydrazono--2,6-dimethyl-1,4-dihydropyridine, and 3,5-bis-thiazoly-2,6-dimethyl-1,4-dihydro pyridines.

This simple oxidation is based upon the in situ generation of nitrous acid from an aqueous sodium nitrite and acetic acid mixture and could be used to downgrade costs, sustain resources, and minimize chemical wastes. Also, a molecular modeling strategy was used to study the mechanism of action for various derivatives of bis-hydrazinylidene-thiazole as the protein Vascular Endothelial Growth Factor Receptor Tyrosine Kinase (VEGFR TK) inhibitor through evaluating their binding scores and modes compared with Sorafenib as a reference standard.

The results revealed that the interaction of hydrazinylidene and thiazole as an anticancer Tyrosine Kinase inhibitor has been improved.

Additionally, the compounds exhibiting the highest activity were assessed for their potential anticancer effects against HepG-2, MCF-7, and WI-38 cells, and the outcomes demonstrated encouraging activity against cancer.

Long COVID is characterized by the persistence of symptoms among individuals who are infected with the SARS-CoV-2 virus. The enduring impact of these long-term effects on the health and well-being of those affected cannot be denied.

470 patients with SARS-CoV-2 were consecutively recruited in this longitudinal study. The participants were entered into moderate, severe, and critical groups. 235 out of 470 participants were female. The levels of fasting blood sugar (FBS), alanine transaminase (SGPT), aspartate aminotransferase (SGOT), alkaline phosphatase (ALP), creatinine (Cr), urea, uric acid (UA), and total protein (TP) were measured during hospitalization and again at one and three months after infection. The levels of Zn and hemoglobin A1c (HbA1c) were also measured only during hospitalization.

COVID-19 severity was associated with high levels of glucose, urea, Cr, ALT, AST, ALP, and HbA1c, and low levels of Zn, UA, and TP. There were significant sex differences for these markers at all three-time points. Glucose, urea, Cr, ALT, AST, and ALP all decreased three months after infection, whereas the levels of UA and TP returned towards normal.

COVID-19 infection affects the levels of multiple biochemical factors in a gender-dependent manner. The biochemical changes become more tangible with increasing disease severity, and several of these predict mortality. Levels begin to return to normal after the acute phase of the disease, but in some individuals, at three months, several markers were still not within the normal range. Whether the trajectory of these changes can predict long COVID requires further testing.

The pandemic caused by SARS-CoV-2 significantly impacted human life around the globe. Numerous unexpected modifications of the SARS-CoV-2 genome have resulted in the emergence of new types and have caused great concern globally.

Inhibitory effects of bioactive phytochemicals derived from natural and synthetic sources are promising for pathogenic viruses. In vitro and in silico techniques were used in the current study to identify novel inhibitors of coumarin clubbed thiazolo[3,2-b][1,2,4]triazoles against the SARS-CoV-2 spike protein.

Interestingly, all the tested molecules demonstrated substantial inhibition of spike protein with 91.81-57.90% inhibition. The spike protein was remarkably inhibited by compounds 6k (91.83%), 6j (89.75%), 6m (87.69%),6i (86.60%), 6l (85.40%), 6h (84.70%), 6l (84.70%), 6g (83.40%), 6b (82.60%), 6f (81.90%), while compounds 6d 6a, 6c, and 6e exhibited significant activity against spike protein with 79.60%, 77.10%, 75.30%, and 57.90% inhibition, respectively. The binding mechanism of these novel inhibitors with spike protein was deduced in silico, which reflects that the active molecules firmly bind with the receptor binding domain (RBD) of spike protein, thereby inhibiting its function.

The combined in vitro and in silico investigations unfold the therapeutic potential of coumarin-thiazolotriazole scaffolds in the treatment of SARS-CoV-2 infection.

Traditional Oriental Medicines (TOMs) formulated using a variety of medicinal plants have a low risk of side effects. In previous studies, five TOMs, namely Dangguijakyaksan, Hwanglyeonhaedoktang, Ukgansan, Palmijihwanghwan, and Jowiseungchungtang have been commonly used to treat patients with Alzheimer’s disease (AD). However, only a few studies have investigated the effects of these five TOMs on tau pathology.

This study aimed to examine the effect of five TOMs on various tau pathologies, including post-translational modifications, aggregation and deposition, tau-induced neurotoxicity, and tau-induced neuroinflammation.

Immunocytochemistry was used to investigate the hyperphosphorylation of tau induced by okadaic acid. In addition, the thioflavin T assay was used to assess the effects of the TOMs on the inhibition of tau K18 aggregation and the dissociation of tau K18 aggregates. Moreover, a water-soluble tetrazolium-1 assay and a quantitative reverse transcription polymerase chain reaction were used to evaluate the effects of the TOMs on tau-induced neurotoxicity and inflammatory cytokines in HT22 and BV2 cells, respectively.

The five TOMs investigated in this study significantly reduced okadaic acid-induced tau hyperphosphorylation. Hwanglyeonhaedoktang inhibited the aggregation of tau and promoted the dissociation of tau aggregates. Dangguijakyaksan and Hwanglyeonhaedoktang attenuated tau-induced neurotoxicity in HT22 cells. In addition, Dangguijakyaksan, Hwanglyeonhaedoktang, Ukgansan, and Palmijihwanghwan reduced tau-induced pro-inflammatory cytokine levels in BV2 cells.

Our results suggest that five TOMs are potential therapeutic candidates for tau pathology. In particular, Hwanglyeonhaedoktang showed the greatest efficacy among the five TOMs in cell-free and cell-based screening approaches. These findings suggest that Hwanglyeonhaedoktang is suitable for treating AD patients with tau pathology.

The molecular mechanism of L-ascorbate (Vitamin C) in the treatment of Chronic Obstructive Pulmonary Disease (COPD) has not been fully explained. In this study, we aimed to explore the potential signaling pathways of L-ascorbate in the treatment of COPD.

The non-targeted metabolomics method was used to analyze the differential metabolites in the blood of healthy subjects and COPD patients. The COPD rat model was established by exposing them to Cigarette Smoke (CS). Network pharmacology, molecular docking, and molecular dynamics simulation analyses were performed to analyze the regulatory pathways of the differential metabolites.

A non-targeted metabolomics analysis revealed metabolic disorders and significantly reduced levels of L-ascorbate in COPD patients compared with healthy subjects. The L-ascorbate intervention reduced lung inflammation and histological damage in COPD rat models. Network pharmacology analysis revealed 280 common targets between L-ascorbate (drug) and COPD (disease), of which seven core targets were MMP3, MME, PCNA, GCLC, SOD2, EDN1, and EGF. According to molecular docking prediction, L-ascorbate had the highest affinity with EGF. Molecular dynamics simulation indicated relatively stable EGF and L-ascorbate complexes. The PI3K/AKT signaling pathway was significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analysis. In vivo and in vitro experiments confirmed that L-ascorbate affected COPD by regulating the EGF/PI3K/AKT pathway.

In summary, based on network pharmacology and molecular docking analyses, this study revealed that L-ascorbate affects COPD development by regulating the PI3K/AKT signaling pathway through EGF and thus contributes to the understanding and clinical application of L-ascorbate in the treatment of COPD.