Current Medicinal Chemistry - Volume 30, Issue 35, 2023

Alpha-lipoic acid (ALA) is a potent antioxidant used in the management of diabetic neuropathy due to its ability to prevent neuronal lipid peroxidation. ALA also chelates transition metals, which can be beneficial in some diseases related to metal overload. Due to its unique antioxidant properties, ALA has potential novel applications in other diseases related to oxidative stress and inflammation. This review summarizes aspects of recent clinical trials and describes the uses of ALA in managing neuropathies. The unique pharmacological actions of ALA, coupled with relatively low toxicity, have led to several trials on the potential therapeutic uses of ALA in the management of diseases associated with increased oxidative stress, inflammation, and metal overload.

Metformin has been used as an oral anti-hyperglycaemic drug since the late 1950s; however, following the release in 1998 of the findings of the 20-year United Kingdom Prospective Diabetes Study (UKPDS), metformin use rapidly increased and today is the first-choice anti-hyperglycaemic drug for patients with type 2 diabetes (T2D). Metformin is in daily use by an estimated 150 million people worldwide. Historically, the benefits of metformin as an anti-diabetic and cardiovascular-protective drug have been linked to effects in the liver, where it acts to inhibit gluconeogenesis and lipogenesis, as well as reduce insulin resistance and enhance peripheral glucose utilization. However, direct protective effects on the endothelium and effects in the gut prior to metformin absorption are now recognized as important. In the gut, metformin modulates the glucagon-like peptide- 1 (GLP-1) - gut-brain axis and impacts the intestinal microbiota. As the apparent number of putative tissue and cellular targets for metformin has increased, so has the interest in re-purposing metformin to treat other diseases that include polycystic ovary syndrome (PCOS), cancer, neurodegenerative diseases, and COVID-19. Metformin is also being investigated as an anti-ageing drug. Of particular interest is whether metformin provides the same level of vascular protection in individuals other than those with T2D, including obese individuals with metabolic syndrome, or in the setting of vascular thromboinflammation caused by SARS-CoV-2. In this review, we critically evaluate the literature to highlight clinical settings in which metformin might be therapeutically repurposed for the prevention and treatment of vascular disease.

Obesity, as an unfavorable consequence of our modern lifestyle, can promote the emergence of other disorders, like diabetes and cardiovascular disease, that negatively impact quality of life. Therefore, prevention and treatment of obesity and its related comorbidities are critical. Lifestyle modification is the first and most important step but, in practical terms, presents a major challenge to many patients. So, the development of new strategies and therapies is critical for these patients. Although herbal bioactive compounds have recently gained attention for their ability to prevent and treat conditions related to obesity, no ideal pharmacological treatment has been found to treat obesity. Curcumin, one of the compounds extracted from turmeric, is a well-studied active herbal extract; however, its poor bioavailability and solubility in water, instability against temperature, light and pH fluctuations and rapid excretion limit its therapeutic application. Curcumin modification can, however, provide novel analogues with better performance and fewer disadvantages in comparison to the original structure. In the past few years, the positive effects of synthetic analogues of curcumin for the treatment of obesity, diabetes and cardiovascular disorders have been reported. In this review, we evaluate the strengths and weaknesses of the reported artificial derivatives and assess their practicality as therapeutic agents.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by marked cognitive decline, memory loss, and spatio-temporal troubles and, in severe cases, lack of recognition of family members. Neurological symptoms, cognitive disturbances, and the inflammatory frame due to COVID-19, together with long-term effects, have fueled renewed interest in AD based on similar damage. COVID-19 also caused the acceleration of AD symptom onset. In this regard, the morbidity and mortality of COVID-19 were reported to be increased in patients with AD due to multiple pathological changes such as excessive expression of the viral receptor angiotensin-converting enzyme 2 (ACE2), comorbidities such as diabetes, hypertension, or drug-drug interactions in patients receiving polypharmacy and the high presence of proinflammatory molecules. Furthermore, the release of cytokines, neuroinflammation, oxidative stress, and ferroptosis in both diseases showed common underlying mechanisms, which together worsen the clinical picture and prognosis of these patients.

Alzheimer’s Disease (AD) is a successive neurodegenerative disorder in the aged population. Many chemicals and phytochemicals are used to treat AD. Polyphenols which occur widely in various fruits, vegetables, beverages, and some other plant sources are gaining importance in AD treatment. Polyphenols comprise various subcategories, such as phenolic acids, lignans, tannins, stilbenes, hydroxybenzoic acid, hydroxycinnamic acid, and flavonoids. These compounds, as sole entities or in combination, can be used for treating AD because they have an abundance of antioxidants that are reported to be effective in free radical scavenging, metal ion chelating, and anti-inflammatory activities. Polyphenols of various plant origins have been studied, and these have been supported by in vitro assays and in vivo studies in rodents. These molecules protect neurons against oxidative stress and deposition of amyloid-β (Aβ) and tau proteins which play a vital role in the pathogenesis of AD. Consumption of wine and other foods rich in polyphenols has a beneficial effect on the neuronal signaling pathways, playing a vital role in shielding neuronal cells from neurodegeneration. Their ability to reduce free radicals and chelate metals are of great advantage. In this review, we highlight the various polyphenols that inhibit neuronal damage and progression of AD while also providing a cure. Some of the polyphenols covered are hesperidin, resveratrol, curcumin, catechin, kaempferol, and quercetin. The mechanisms of the actions of three polyphenols are also elaborated.