**1. Introduction**

AGEs are a complex and highly reactive group of heterogeneous compounds produced by glycation of proteins by reducing sugars [1,2]. Protein glycation has been shown to increase the accumulation of AGEs, the production and release of reactive oxygen species (ROS), and the structural and functional alteration of proteins, as well as resulting in tissue damage [3,4]. AGEs interact with particular receptors or bind proteins, activating a number of signaling pathways implicated in diabetic complications such as nephropathy, cataracts, Alzheimer's disease, and atherosclerosis, among others [5,6]. Glycation, AGEs, and oxidative stress have all been linked to a variety of health problems [7]. The states of

**Citation:** Khan, M.W.A.; Otaibi, A.A.; Alsukaibi, A.K.D.; Alshammari, E.M.; Al-Zahrani, S.A.; Sherwani, S.; Khan, W.A.; Saha, R.; Verma, S.R.; Ahmed, N. Biophysical, Biochemical, and Molecular Docking Investigations of Anti-Glycating, Antioxidant, and Protein Structural Stability Potential of Garlic. *Molecules* **2022**, *27*, 1868. https://doi.org/10.3390/ molecules27061868

Academic Editors: Tanveer A. Wani, Seema Zargar and Afzal Hussain

Received: 8 February 2022 Accepted: 9 March 2022 Published: 14 March 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

total metabolic burden, chronic hyperglycemia, oxidative stress, and inflammation have been linked to an excessive buildup of AGEs [8].

In chronic inflammation, such as that observed in rheumatoid arthritis (RA), AGEs are produced and can accumulate in tissues [9]. Besides, AGEs build with age and promote pathologic stiffening of cartilage and extracellular matrix. Pentosidine is an AGE, and it is found in blood, synovial fluid, and articular cartilage of osteoarthritis patients [9]. AGEs are linked with endothelial activation and endothelial dysfunction [10]. As a result, AGEs have been suggested as an early biomarker for cardiovascular disease [11].

Intracellular ROS inhibit glucose consumption and cause oxidative alteration of intracellular proteins. Such exposure of protein can result in fragmentation, aggregation, oxidative phosphorylation, and unwanted interactions with ion channel-coupled receptors [12]. An excessive generation of free radicals/ROS leads to oxidative stress, which is involved in the development of inflammatory illnesses such as diabetes, cancer, cardiovascular disease, Parkinson's disease, Alzheimer's disease, and aging. Chronic inflammation is involved in tumor development. Tissue damage and endothelial dysfunction arise from increased ROS generation at the site of inflammation, leading to inflammatory diseases [13].

Inhibition of glycation has also been shown to be beneficial in the treatment of diabetic complications [14]. Synthetic chemicals are powerful anti-glycating agents, but they can also have serious side effects such as gastrointestinal problems, uncommon vasculitis, anemia, flu-like symptoms, nausea, and diarrhea. Thus, a lot of interest has been focused on finding natural plant phytochemicals that efficiently prevent glycation and produce fewer adverse side effects. Traditional medicine practitioners frequently employ medicinal plants and natural products in their everyday practice to treat a variety of illnesses because they are generally non-toxic, cheap, ingestible, and have fewer adverse effects. [4]. The medicinal properties of garlic (*Allium sativum*) were well documented in Sanskrit literature 5000 years ago, and its use in Chinese medicine was also reported as far back as 3000 years ago. The healing properties of garlic were well known in the ancient world and utilized by the Egyptians, Babylonians, Greeks, and Romans [15]. Louis Pasteur documented the antibacterial activity of garlic in 1858. Due to its healing potential and antiseptic properties, it was used to treat and prevent gangrene during the Second World War [16]. The overall benefits of garlic in maintaining good health and in preventing a range of health issues has shifted the focus of modern-day medicine back to a time-tested natural remedy. The therapeutic roles of garlic are supported by modern-day epidemiologic evidence, with studies indicating the benefits of garlic preparations in having antioxidant and antimicrobial effects and in reducing diabetes, cardiovascular disease, and cancer [17,18]. This study focused on investigating the anti-glycation and antioxidative stress activities of garlic extract, as well as conducting an in-depth study of the secondary structural alterations of HSA proteins and how garlic extract metabolites might inhibit the glycation reactions in addition to inhibiting secondary structure alterations. This study provides a platform for the future studies in this direction, which may potentially elucidate physiological and immunological imbalances.
