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image of Metformin Protects Human Insulin from Fructosylation: An In Vitro Biochemical Study

Abstract

Introduction

Fructose, like other sugars and sugar metabolites, is capable of glycating protein. Insulin's fructosylation leads to the generation of Advanced Glycation End Products (AGEs). Reducing sugars reaction with proteins to form Schiff’s bases, which are characterized by the presence of an imine (C=N) bond. The Schiff bases then undergo irreversible rearrangements, followed by the production of much more stable compounds called Amadori products. These Amadori products can further undergo oxidation, dehydration, cyclization, and condensation to form highly toxic advanced glycation end-products (AGEs). These processes are accompanied by oxidative stress, secondary structural perturbations, and altered morphology, progressing toward amyloidogenesis. Metformin, a biguanide, is the most common drug used to treat type 2 Diabetes Mellitus (T2DM).

Aim

The aim of this study was to evaluate the protective effect of metformin against fructosylation-induced cross-β structures and amyloid aggregations of human insulin.

Methods

UV-absorbance and fluorescence spectroscopy, determination of carbonyl content, free lysine and arginine residues, determination of fructosamine content, SDS-PAGE, circular dichroism (CD) spectroscopy, dynamic light scattering, and scanning and transmission electron microscopy.

Results

Physicochemical studies in the presence or absence of metformin revealed a concentration-dependent structural restoration of fructosylated insulin. Results from the thioflavin-T fluorescence assay suggested that metformin limited the transition of insulin from native to fibrillar state, which was validated by scanning and transmission electron microscopy. Metformin lowered the ThT fluorescence intensity in a concentration-dependent manner. The ThT-specific fluorescence intensity was reduced to 114 and 112.5%. The fluorescence intensity at 2.5 mM metformin was close to native insulin. Electron microscopy revealed that insulin fructosylated by 25 mM fructose in the presence of 2.5 mM metformin suppressed the formation of fibrillar structures. Dynamic light scattering data revealed the potential of metformin to conserve and reinstate the increased hydrodynamic radii (R) of fructosylated insulin close to the native conformer. The R values of native, fructosylated insulin and insulin incubated with fructose and metformin were found to be 2.65 ± 0.28, 307.6 ± 24.19 nm, and 110.1 ± 4.08 nm, respectively. This study also identified metformin as an antioxidant by protecting critical amino acid residues of the insulin domain.

Discussion

The study reports the protective effects of metformin on insulin structure, conformation, and function. The findings suggest a potential role for metformin in improving the risk profile associated with insulin resistance due to altered structure or the accumulation of protein aggregates. Interaction studies between insulin and metformin presented here are due to the chemical effect; hence, further in-depth studies are required to identify the molecular mechanism of insulin sensitivity and changes in cellular processes and pathways.

Conclusion

The results suggest that metformin safeguards against fructosylation-induced structural, conformational, morphological, and amyloidogenic aggregating tendencies of insulin. Protein aggregation has been linked to several neurological and metabolic diseases. Hence, metformin may be crucial in preserving the biological activity of insulin by maintaining and protecting its structural integrity and minimizing the associated comorbidities. The study may further be extended to identify the role of metformin in controlling the gradual insulin resistance in T2DM at the molecular level.

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2025-06-02
2025-09-11
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References

  1. Cho N.H. Shaw J.E. Karuranga S. Huang Y. da Rocha Fernandes J.D. Ohlrogge A.W. Malanda B. IDF Diabetes Atlas: Global estimates of diabetes prevalence for 2017 and projections for 2045. Diabetes Res. Clin. Pract. 2018 138 271 281 10.1016/j.diabres.2018.02.023 29496507
    [Google Scholar]
  2. Nowotny K. Jung T. Höhn A. Weber D. Grune T. Advanced glycation end products and oxidative stress in type 2 diabetes mellitus. Biomolecules 2015 5 1 194 222 10.3390/biom5010194 25786107
    [Google Scholar]
  3. Darenskaya M.A. Kolesnikova L.I. Kolesnikov S.I. Oxidative stress: Pathogenetic role in diabetes mellitus and its complications and therapeutic approaches to correction. Bull. Exp. Biol. Med. 2021 171 2 179 189 10.1007/s10517‑021‑05191‑7 34173093
    [Google Scholar]
  4. Jakas A. Katić A. Bionda N. Horvat Š. Glycation of a lysine-containing tetrapeptide by d-glucose and d-fructose—influence of different reaction conditions on the formation of Amadori/Heyns products. Carbohydr. Res. 2008 343 14 2475 2480 10.1016/j.carres.2008.07.003 18656854
    [Google Scholar]
  5. Takeuchi M. Iwaki M. Takino J. Shirai H. Kawakami M. Bucala R. Yamagishi S. Immunological detection of fructose-derived advanced glycation end-products. Lab. Invest. 2010 90 7 1117 1127 10.1038/labinvest.2010.62 20212455
    [Google Scholar]
  6. Gugliucci A. Formation of fructose-mediated advanced glycation end products and their roles in metabolic and inflammatory diseases. Adv. Nutr. 2017 8 1 54 62 10.3945/an.116.013912 28096127
    [Google Scholar]
  7. Bray G.A. Nielsen S.J. Popkin B.M. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. Am. J. Clin. Nutr. 2004 79 4 537 543 10.1093/ajcn/79.4.537 15051594
    [Google Scholar]
  8. Zaman A. Arif Z. Moinuddin Alam K. Fructose-human serum albumin interaction undergoes numerous biophysical and biochemical changes before forming AGEs and aggregates. Int. J. Biol. Macromol. 2018 109 896 906 10.1016/j.ijbiomac.2017.11.069 29133088
    [Google Scholar]
  9. Gugliucci A. Formation of fructose-mediated advanced glycation end products and their roles in metabolic and inflammatory diseases. Adv. Nutr. 2017 8 1 54 62 10.3945/an.116.013912 28096127
    [Google Scholar]
  10. Zhao H.R. Smith J.B. Jiang X.Y. Abraham E.C. Sites of glycation of β B2-crystallin by glucose and fructose. Biochem. Biophys. Res. Commun. 1996 229 1 128 133 10.1006/bbrc.1996.1768 8954094
    [Google Scholar]
  11. Gabbay K.H. Kinoshita J.H. Mechanism of development and possible prevention of sugar cataracts. Isr. J. Med. Sci. 1972 8 8 1557 1561 4647820
    [Google Scholar]
  12. Hinton D.J.S. Ames J.M. Site specificity of glycation and carboxymethylation of bovine serum albumin by fructose. Amino Acids 2006 30 4 425 434 10.1007/s00726‑006‑0269‑2 16583308
    [Google Scholar]
  13. Scivittaro V. Ganz M.B. Weiss M.F. AGEs induce oxidative stress and activate protein kinase C-β II in neonatal mesangial cells. Am. J. Physiol. Renal Physiol. 2000 278 4 F676 F683 10.1152/ajprenal.2000.278.4.F676 10751230
    [Google Scholar]
  14. Gracia K.C. Llanas-Cornejo D. Husi H. CVD and oxidative stress. J. Clin. Med. 2017 6 2 22 10.3390/jcm6020022 28230726
    [Google Scholar]
  15. Chellan P. Nagaraj R.H. Protein crosslinking by the Maillard reaction: dicarbonyl-derived imidazolium crosslinks in aging and diabetes. Arch. Biochem. Biophys. 1999 368 1 98 104 10.1006/abbi.1999.1291 10415116
    [Google Scholar]
  16. Verzijl N. DeGroot J. Zaken C.B. Braun-Benjamin O. Maroudas A. Bank R.A. Mizrahi J. Schalkwijk C.G. Thorpe S.R. Baynes J.W. Bijlsma J.W.J. Lafeber F.P.J.G. TeKoppele J.M. Crosslinking by advanced glycation end products increases the stiffness of the collagen network in human articular cartilage: A possible mechanism through which age is a risk factor for osteoarthritis. Arthritis Rheum. 2002 46 1 114 123 10.1002/1529‑0131(200201)46:1<114::AID‑ART10025>3.0.CO;2‑P 11822407
    [Google Scholar]
  17. Ighodaro O.M. Molecular pathways associated with oxidative stress in diabetes mellitus. Biomed. Pharmacother. 2018 108 656 662 10.1016/j.biopha.2018.09.058 30245465
    [Google Scholar]
  18. Caughey B. Lansbury P.T. Jr. Protofibrils, pores, fibrils, and neurodegeneration: Separating the responsible protein aggregates from the innocent bystanders. Annu. Rev. Neurosci. 2003 26 1 267 298 10.1146/annurev.neuro.26.010302.081142 12704221
    [Google Scholar]
  19. Laurén J. Gimbel D.A. Nygaard H.B. Gilbert J.W. Strittmatter S.M. Cellular prion protein mediates impairment of synaptic plasticity by amyloid-β oligomers. Nature 2009 457 7233 1128 1132 10.1038/nature07761 19242475
    [Google Scholar]
  20. Li S. Leblanc R.M. Aggregation of insulin at the interface. J. Phys. Chem. B 2014 118 5 1181 1188 10.1021/jp4101202 24328184
    [Google Scholar]
  21. Schofield C.J. Sutherland C. Disordered insulin secretion in the development of insulin resistance and Type 2 diabetes. Diabet. Med. 2012 29 8 972 979 10.1111/j.1464‑5491.2012.03655.x 22443306
    [Google Scholar]
  22. Raza A. Mahmood R. Habib S. Talha M. Khan S. Hashmi M.A. Mohammad T. Ali A. Fructosylation of human insulin causes AGEs formation, structural perturbations and morphological changes: An in silico and multispectroscopic study. J. Biomol. Struct. Dyn. 2023 41 12 5850 5862 10.1080/07391102.2022.2098820 35869652
    [Google Scholar]
  23. Hunter R.W. Hughey C.C. Lantier L. Sundelin E.I. Peggie M. Zeqiraj E. Sicheri F. Jessen N. Wasserman D.H. Sakamoto K. Metformin reduces liver glucose production by inhibition of fructose-1-6-bisphosphatase. Nat. Med. 2018 24 9 1395 1406 10.1038/s41591‑018‑0159‑7 30150719
    [Google Scholar]
  24. Bailey C.J. Metformin: Effects on micro and macrovascular complications in type 2 diabetes. Cardiovasc. Drugs Ther. 2008 22 3 215 224 10.1007/s10557‑008‑6092‑0 18288595
    [Google Scholar]
  25. Regan T.J. Jyothirmayi G.N. Laham C. Jain A. Left ventricular diastolic dysfunction in diabetic or hypertensive subjects: Role of collagen alterations. Adv. Exp. Med. Biol. 2001 498 127 132 10.1007/978‑1‑4615‑1321‑6_17 11900360
    [Google Scholar]
  26. Tanaka Y. Uchino H. Shimizu T. Yoshii H. Niwa M. Ohmura C. Mitsuhashi N. Onuma T. Kawamori R. Effect of metformin on advanced glycation endproduct formation and peripheral nerve function in streptozotocin-induced diabetic rats. Eur. J. Pharmacol. 1999 376 1-2 17 22 10.1016/S0014‑2999(99)00342‑8 10440084
    [Google Scholar]
  27. Twarda-Clapa A. Olczak A. Białkowska A.M. Koziołkiewicz M. Advanced glycation end-products (AGEs): Formation, chemistry, classification, receptors, and diseases related to AGEs. Cells 2022 11 8 1312 10.3390/cells11081312 35455991
    [Google Scholar]
  28. Alenazi F. Saleem M. Khaja A.S.S. Zafar M. Alharbi M.S. Hagbani T.A. Ashraf J.M. Qamar M. Rafi Z. Ahmad S. Metformin encapsulated gold nanoparticles (MTF-GNPs): A promising antiglycation agent. Cell Biochem. Funct. 2022 40 7 729 741 10.1002/cbf.3738 36098489
    [Google Scholar]
  29. Talha M. Mir A.R. Habib S. Abidi M. Warsi M.S. Islam S. Moinuddin. Hydroxyl radical induced structural perturbations make insulin highly immunogenic and generate an auto-immune response in type 2 diabetes mellitus. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2021 255 119640 10.1016/j.saa.2021.119640 33744841
    [Google Scholar]
  30. Levine R.L. Garland D. Oliver C.N. Amici A. Climent I. Lenz A.G. Ahn B.W. Shaltiel S. Stadtman E.R. Determination of carbonyl content in oxidatively modified proteins. Methods Enzymol. 1990 186 464 478 10.1016/0076‑6879(90)86141‑H 1978225
    [Google Scholar]
  31. Khan M.Y. Alouffi S. Ahmad S. Immunochemical studies on native and glycated LDL – An approach to uncover the structural perturbations. Int. J. Biol. Macromol. 2018 115 287 299 10.1016/j.ijbiomac.2018.04.016 29634967
    [Google Scholar]
  32. Smith R.E. MacQuarrie R. A sensitive fluorometric method for the determination of arginine using 9,10-phenanthrenequinone. Anal. Biochem. 1978 90 1 246 255 10.1016/0003‑2697(78)90029‑5 727468
    [Google Scholar]
  33. Chayaratanasin P. Barbieri M.A. Suanpairintr N. Adisakwattana S. Inhibitory effect of Clitoria ternatea flower petal extract on fructose-induced protein glycation and oxidation-dependent damages to albumin in vitro. BMC Complement. Altern. Med. 2015 15 1 27 10.1186/s12906‑015‑0546‑2
    [Google Scholar]
  34. Tufail N. Abidi M. Warsi M.S. Kausar T. Nayeem S.M. Computational and physicochemical insight into 4-hydroxy-2-nonenal induced structural and functional perturbations in human low-density lipoprotein. J. Biomol. Struct. Dyn. 2024 42 5 2698 2713 10.1080/07391102.2023.2208234 37154523
    [Google Scholar]
  35. Ahmad R. Warsi M.S. Abidi M. Habib S. Siddiqui S. Khan H. Nabi F. Moinuddin. Structural perturbations induced by cumulative action of methylglyoxal and peroxynitrite on human fibrinogen: An in vitro and in silico approach. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2024 307 123500 10.1016/j.saa.2023.123500 37989033
    [Google Scholar]
  36. Warsi M.S. Habib S. Talha M. Khan S. Singh P. Mir A.R. Abidi M. Ali A. 4-chloro-1,2-phenylenediamine induced structural perturbation and genotoxic aggregation in human serum albumin. Front Chem 2022 10 1016354 10.3389/fchem.2022.1016354 36199663
    [Google Scholar]
  37. Ahmad S. Shahab U. Baig M.H. Khan M.S. Khan M.S. Srivastava A.K. Saeed M. Moinuddin. Inhibitory effect of metformin and pyridoxamine in the formation of early, intermediate and advanced glycation end-products. PLoS One 2013 8 9 e72128 10.1371/journal.pone.0072128 24023728
    [Google Scholar]
  38. Beisswenger P. Ruggiero-Lopez D. Metformin inhibition of glycation processes. Diabetes Metab 2003 29 4 Pt 2 6S95 103 10.1016/s1262‑3636(03)72793‑1 14502106
    [Google Scholar]
  39. Iannuzzi C. Irace G. Sirangelo I. Differential effects of glycation on protein aggregation and amyloid formation. Front. Mol. Biosci. 2014 1 9 10.3389/fmolb.2014.00009 25988150
    [Google Scholar]
  40. dos Santos M.M. Prestes A.S. de Macedo G.T. Ecker A. Barcelos R.P. Boligon A.A. Souza D. de Bem A.F. da Rocha J.B.T. Barbosa N.V. Syzygium cumini leaf extract inhibits LDL oxidation, but does not protect the liproprotein from glycation. J. Ethnopharmacol. 2018 210 69 79 10.1016/j.jep.2017.08.033 28844679
    [Google Scholar]
  41. Szwergold B. A hypothesis: Fructosamine-3-kinase-related-protein (fn3krp) catalyzes deglycation of maillard intermediates directly downstream from fructosamines. Rejuvenation Res. 2021 24 4 310 318 10.1089/rej.2021.0009 34314247
    [Google Scholar]
  42. Ali S.M. Nabi F. Furkan M. Hisamuddin M. Malik S. Zakariya S.M. Rizvi I. Uversky V.N. Khan R.H. Tuning the aggregation behavior of human insulin in the presence of luteolin: An in vitro and in silico approach. Int. J. Biol. Macromol. 2023 237 124219 10.1016/j.ijbiomac.2023.124219 36990415
    [Google Scholar]
  43. Yamagishi S. Matsui T. Role of hyperglycemia-induced advanced glycation end product (AGE) accumulation in atherosclerosis. Ann. Vasc. Dis. 2018 11 3 253 258 10.3400/avd.ra.18‑00070 30402172
    [Google Scholar]
  44. Adeshara K.A. Bangar N.S. Doshi P.R. Diwan A. Tupe R.S. Action of metformin therapy against advanced glycation, oxidative stress and inflammation in type 2 diabetes patients: 3 months follow-up study. Diabetes Metab. Syndr. 2020 14 5 1449 1458 10.1016/j.dsx.2020.07.036 32769032
    [Google Scholar]
  45. Szkudlarek A. Pentak D. Ploch A. Pożycka J. Maciążek-Jurczyk M. In vitro investigation of the interaction of tolbutamide and losartan with human serum albumin in hyperglycemia states. Molecules 2017 22 12 2249 10.3390/molecules22122249 29258218
    [Google Scholar]
  46. Lopes J.L.S. Miles A.J. Whitmore L. Wallace B.A. Distinct circular dichroism spectroscopic signatures of polyproline II and unordered secondary structures: Applications in secondary structure analyses. Protein Sci. 2014 23 12 1765 1772 10.1002/pro.2558 25262612
    [Google Scholar]
  47. Pereira Morais M.P. Marshall D. Flower S.E. Caunt C.J. James T.D. Williams R.J. Waterfield N.R. van den Elsen J.M.H. Analysis of protein glycation using fluorescent phenylboronate gel electrophoresis. Sci. Rep. 2013 3 1 1437 10.1038/srep01437 23531746
    [Google Scholar]
  48. Kang Y.J. Jeong H.C. Kim T.E. Shin K.H. Bioanalytical method using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPL-CHRMS) for the detection of metformin in human plasma. Molecules 2020 25 20 4625 10.3390/molecules25204625 33050662
    [Google Scholar]
  49. Roy H. Brahma C. Nandi S. Parida K. Formulation and design of sustained release matrix tablets of metformin hydrochloride: Influence of hypromellose and polyacrylate polymers. Int. J. Appl. Basic Med. Res. 2013 3 1 55 63 10.4103/2229‑516X.112242 23776841
    [Google Scholar]
  50. Mandal B.M. Conducting polyaniline: Dispersions, nanoparticles and nanocomposites. J. Indian Chem. Soc. 1997 75 121 129
    [Google Scholar]
  51. Roy T.T. Sarbadhikary S.B. Guha A.K. Mandal B.M. Bhattacharyya S.N. On the estimation of biological oxygen demand of collected water samples with special reference to that of the Ganges water. J. Indian Chem. Soc. 1996 73 472 475
    [Google Scholar]
  52. Bhattacharyya C. Bhattacharyya S.N. Mandal B.M. Poly (vinyl propionate) and Poly (ethyl acrylate)-A miscible polymer pairt. J. Indian Chem. Soc. 1986 63 157 160
    [Google Scholar]
  53. Flory P.J. Thermodynamics of high polymer solutions. J. Chem. Phys. 1942 10 1 51 61 10.1063/1.1723621
    [Google Scholar]
  54. Flory P.J. Principles of Polymer Chemistry. Cornell University Press Ithaca, NY 1953
    [Google Scholar]
  55. Klueppelberg J. Handge U.A. Thommes M. Winck J. Composition dependency of the flory–huggins interaction parameter in drug–Polymer phase behavior. Pharmaceutics 2023 15 12 2650 10.3390/pharmaceutics15122650 38139992
    [Google Scholar]
  56. Rana D. Bag K. Bhattacharyya S.N. Mandal B.M. Miscibility of poly(styrene-co-butyl acrylate) with poly(ethyl methacrylate): Existence of both UCST and LCST. J. Polym. Sci., B, Polym. Phys. 2000 38 3 369 375 10.1002/(SICI)1099‑0488(20000201)38:3<369::AID‑POLB3>3.0.CO;2‑W
    [Google Scholar]
  57. Rana D. Mandal B.M. Bhattacharyya S.N. Analogue calorimetric studies of blends of poly (vinyl ester)s and polyacrylates. Macromolecules 1996 29 5 1579 1583 10.1021/ma950954n
    [Google Scholar]
  58. Rana D. Mandal B.M. Bhattacharyya S.N. Analogue calorimetry of polymer blends: poly(styrene-co-acrylonitrile) and poly(phenyl acrylate) or poly(vinyl benzoate). Polymer 1996 37 12 2439 2443 10.1016/0032‑3861(96)85356‑0
    [Google Scholar]
  59. Rana D. Mandal B.M. Bhattacharyya S.N. Miscibility and phase diagrams of poly(phenyl acrylate) and poly(styrene-co-acrylonitrile) blends. Polymer 1993 34 7 1454 1459 10.1016/0032‑3861(93)90861‑4
    [Google Scholar]
  60. Huang S.J. Gokulkumar K. Govindasamy M. Albaqami M.D. Wabaidur S.M. Nanoarchitectonics of europium vanadate nanoparticles decorated carbon nanofibers for electrochemical detection of fungicide in fruits. J. Taiwan Inst. Chem. Eng. 2024 161 105563
    [Google Scholar]
  61. Remila A. Shally V. Parvathiraja C. Darwin T. Dharshini M.P. Jayam T.G. Wabaidur S.M. Siddiqui M.R. Superior performance of nickel doped vanadium pentoxide nanoparticles and their photocatalytic, antibacterial and antioxidant activities. Res. Chem. Intermed. 2024 50 7 3009 3031 10.1007/s11164‑024‑05316‑3
    [Google Scholar]
  62. Li L. Dai X. Lu M. Guo C. Wabaidur S.M. Wu X.L. Lou Z. Zhong Y. Hu Y. Electron-enriched single-Pd-sites on g-C3N4 nanosheets achieved by in-situ anchoring twinned Pd nanoparticles for efficient CO2 photoreduction. Advanced Powder Materials 2024 3 2 100170 10.1016/j.apmate.2024.100170
    [Google Scholar]
  63. El-Baz Y.G. Moustafa A. Ali M.A. El-Desoky G.E. Wabaidur S.M. Iqbal A. Green synthesized silver nanoparticles for the treatment of diabetes and the related complications of hyperlipidemia and oxidative stress in diabetic rats. Exp. Biol. Med. (Maywood) 2023 248 23 2237 2248 10.1177/15353702231214258 38205769
    [Google Scholar]
  64. Mishra P. Faruqui T. Akhtar S. Nadeem I. Khan I. Wabaidur S.M. Kazi M. Rahim M. Rafi Z. Khan S. Antiproliferative activity of gold and silver nanoparticles fabricated using bark extract of Murraya koenigii. J. Drug Deliv. Sci. Technol. 2023 89 105014 10.1016/j.jddst.2023.105014
    [Google Scholar]
  65. El-Baz Y.G. Moustafa A. Ali M.A. El-Desoky G.E. Wabaidur S.M. Faisal M.M. An analysis of the toxicity, antioxidant, and anti-cancer activity of cinnamon silver nanoparticles in comparison with extracts and fractions of Cinnamomum cassia at normal and cancer cell levels. Nanomaterials 2023 13 5 945 10.3390/nano13050945 36903823
    [Google Scholar]
  66. Prabula S.S. Hentry C. Rose B.L. Parvathiraja C. Mani A. Wabaidur S.M. Eldesoky G.E. Islam M.A. Synthesis of silver nanoparticles by using Cassia auriculata flower extract and their photocatalytic behavior. Chem. Eng. Technol. 2022 45 11 1919 1925 10.1002/ceat.202200082
    [Google Scholar]
  67. Kučuk N. Primožič M. Knez Ž. Leitgeb M. Sustainable biodegradable biopolymer-based nanoparticles for healthcare applications. Int. J. Mol. Sci. 2023 24 4 3188 10.3390/ijms24043188 36834596
    [Google Scholar]
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