Mechanisms of inhibition of advanced glycation end-products (AGEs) and α-glucosidase by Heliotropium bacciferum: Spectroscopic and molecular docking analysis.

Diabetes mellitus is characterized by hyperglycemia that makes insulin more prone to glycation and form advanced glycation end products (AGEs). Here, we report the effect of glyoxal (GO) on the formation of AGEs using human insulin as model protein and their structural modifications. The present investigation also reports the anti-AGE potential of Heliotropium bacciferum (Leaf) extracts. The phytochemical analysis of H. bacciferum revealed that free phenolic extract contains higher amount of total phenolic (3901.58 ± 17.06 mg GAE/100 g) and total flavonoid content (30.41 ± 0.32 mg QE/100 g) when compared to bound phenolic extract. Naringin and caffeic acid were identified as the major phenolic ingredients by UPLC-PAD method. Furthermore, bound phenolics extract showed significantly higher DPPH and superoxide radicals scavenging activity (IC50 17.53 ± 0.36 µg/mL and 0.306 ± 0.038 mg/ mL, respectively) (p ≤ 0.05). Besides, the bound phenolics extract also showed significant (p ≤ 0.05) chelating power (IC50 0.063) compared to free phenolic extract. In addition, bound phenolic extract could efficiently trap GO under physiological conditions. Spectroscopic investigation of GO-modified insulin illustrated changes in the tertiary structure of insulin and formation of AGEs. On the other hand, no significant alteration in secondary structure was observed by far UV-CD measurement. Furthermore, H. bacciferum extract inhibited α-glucosidase activity and AGEs formation implicated in diabetes. Molecular docking analysis depicted that GO bind with human insulin in both chains and forms a stable complex with TYR A: 14, LEU A:13, ASN B:3, SER A:12 amino acid residues with binding energy of - 2.53 kcal/mol. However, caffeic acid binds to ASN A:18 and GLU A:17 residues of insulin with lower binding energy of -4.67 kcal/mol, suggesting its higher affinity towards human insulin compared to GO. Our finding showed promising activity of H. bacciferum against AGEs and its complications. The major phenolics like caffeic acid, naringin and their derivatives could be exploited for the drug development for management of AGEs in diabetes.

Structure-guided identification of potent inhibitors of ROS1 kinase for therapeutic development against non-small cell lung cancer.

Proto-oncogene tyrosine-protein kinase ROS (ROS1) is a member of the sevenless receptor, which affects epithelial cell differentiation and is highly expressed in a variety of tumor cells. The elevated expression and dysfunction of ROS1 have been involved in various malignancies, such as non-small cell lung cancer (NSCLC), stomach cancer, ovarian, breast cancer, cholangiocarcinoma, colorectal cancer, adenosarcoma, oesophageal cancer, etc. ROS1 has been postulated as a potential drug target in anticancer therapeutics. In this study, we carried out a virtual screening of phytochemicals against ROS1 to identify its potential inhibitors. The virtual screening process was performed on the ROS1 structure, where two phytochemicals, Helioscopinolide C and Taiwanin C, were identified. These compounds resulted from filters like Lipinski rule of five, PAINS filter, binding affinities values, and all-atom molecular dynamics (MD) simulations followed by principal component analysis (PCA) and essential dynamics. The findings of this study highlight the role of ROS1 in multiple physiological candidates and its therapeutic targeting using phytochemicals. This study suggests Helioscopinolide C and Taiwanin C as potential compounds for therapeutic development targeting ROS1-associated non-small cell lung cancer for clinical applications. Further in vitro and in vivo experiments are required to validate these findings.Communicated by Ramaswamy H. Sarma.

Effect of a polyherbal formulation on L-thyroxine induced hyperthyroidism in a rat model: In vitro and in vivo analysis and identification of bioactive phytochemicals.

An excess of thyroid hormones in the blood characterizes hyperthyroidism. Long-term use of prescription medications to treat hyperthyroidism has substantial adverse effects and when discontinued, the symptoms frequently recur. Several plant species have been utilized to cure hyperthyroidism. In the present work, we investigated the impact of polyherbal extract (POH) of four medicinal plants to treat hyperthyroidism. Biochemical analysis revealed the presence of a high concentration of phytochemicals in the POHs. The in vitro antioxidant study revealed their antioxidant and free radical scavenging capacity. The gas chromatography coupled mass spectrometry analysis of the POHs showed the presence of 13 bioactive phytochemical compounds. The effect of various concentrations of POHs on L-thyroxine-induced hyperthyroidism in Wistar albino rats was evaluated for 18 days. The TSH, T3 and T4 levels increased significantly and reduced the increase of liver enzymes caused by hyperthyroidism in POH-treated rats. The data showed that POH therapy could restore thyroid function to normal. The injection of POH increased the size comprising vacuolated cells, columnar follicular cells and highly coloured nuclei with increasing POH content and the number of normal thyroid follicles rose. The findings indicate that polyherbal formulations of these medicinal plants include credible antithyroid compounds that may offer a protective and an effective alternative treatment to synthetic thyroid medications.

Modification of chickpea cystatin by reactive dicarbonyl species: Glycation, oxidation and aggregation.

Reactive dicarbonyl species such as methylglyoxal (MGO) and glyoxal (GO) have recently received extensive attention due to their high reactivity and ability to modify biological substances such as proteins, phospholipids, and DNA. In case of proteins these reactive species mainly react with lysine and arginine residues to form AGEs, oxidative products, and aggregates. Chickpea cystatin (CPC) was incubated with varying concentrations of glyoxal and methylglyoxal which caused, along with altered secondary and tertiary structures, glycation, functional inactivation, altered redox state, cross-linking and high-molecular-mass aggregation. All these processes were examined and characterized by UV-Vis, fluorescence, and CD spectroscopies. Further characterization of CPC modified by reactive dicarbonyls was done by polyacrylamide gel electrophoresis which also showed alterations in the CPC molecules. Thus, in addition to describing the effects of GO and MGO on structure, conformation and function of CPC, this study also shows the relatively superior modifying effect of methylglyoxal for CPC in terms of glycation, oxidation and aggregation. This model system could shed some more light on the role of the reactive dicarbonyls in the specific alterations of proteins with different biological consequences having implications to ageing and disease such as diabetes.