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Biomolecular interaction of a platelet aggregation inhibitor, 3,4-methylenedioxy-β-nitrostyrene with human serum albumin: multi-spectral and computational characterization

Kabir MZ, Roslan AA, Ridzwan NFW, Mohamad SB, Tayyab S

J Biomol Struct Dyn, 2020 Jun;38(9):2693-2703.
PMID: 31271347 DOI: 10.1080/07391102.2019.1640133

Molecular interaction of the 3,4-methylenedioxy-β-nitrostyrene (MNS), an inhibitor of platelet aggregation with the main transport protein, albumin from human serum (HSA) was explored using absorption, fluorescence and circular dichroism (CD) spectroscopy in combination with in silico analyses. The MNS-HSA complexation was corroborated from the fluorescence and absorption spectral results. Implication of static quenching mechanism for MNS-HSA system was predicted from the Stern-Volmer constant, KSV-temperature relationship as well as the bimolecular quenching rate constant, kq values. Stabilization of the complex was affirmed by the value of the binding constant (Ka = 0.56-1.48 × 104 M-1). Thermodynamic data revealed that the MNS-HSA association was spontaneously driven mainly through hydrophobic interactions along with van der Waal's interaction and H-bonds. These results were well supported by in silico interpretations. Far-UV and near-UV CD spectral results manifested small variations in the protein's secondary and tertiary structures, respectively, while three-dimensional fluorescence spectra displayed microenvironmental fluctuations around protein's fluorophores, upon MNS binding. Significant improvement in the protein's thermostability was evident from the temperature-stability results of MNS-bound HSA. Binding locus of MNS, as identified by competitive drug displacement findings as well as in silico analysis, was found to be located in subdomain IIA (Sudlow's site I) of the protein.Communicated by Ramaswamy H. Sarma.
Biophysical and computational characterization of vandetanib-lysozyme interaction

Kabir MZ, Hamzah NAB, Ghani H, Mohamad SB, Alias Z, Tayyab S

Spectrochim Acta A Mol Biomol Spectrosc, 2018 Jan 15;189:485-494.
PMID: 28843881 DOI: 10.1016/j.saa.2017.08.051

Interaction of an anticancer drug, vandetanib (VDB) with a ligand transporter, lysozyme (LYZ) was explored using multispectroscopic techniques, such as fluorescence, absorption and circular dichroism along with computational analysis. Fluorescence data and absorption results confirmed VDB-LYZ complexation. VDB-induced quenching was characterized as static quenching based on inverse correlation of KSV with temperature as well as kq values. The complex was characterized by the weak binding constant (Ka=4.96-3.14×103M-1). Thermodynamic data (ΔS=+12.82Jmol-1K-1; ΔH=-16.73kJmol-1) of VDB-LYZ interaction revealed participation of hydrophobic and van der Waals forces along with hydrogen bonds in VDB-LYZ complexation. Microenvironmental perturbations around tryptophan and tyrosine residues as well as secondary and tertiary structural alterations in LYZ upon addition of VDB were evident from the 3-D fluorescence, far- and near-UV CD spectral analyses, respectively. Interestingly, addition of VDB to LYZ significantly increased protein's thermostability. Molecular docking results suggested the location of VDB binding site near the LYZ active site while molecular dynamics simulation results suggested stability of VDB-LYZ complex. Presence of Mg2+, Ba2+ and Zn2+ was found to interfere with VDB-LYZ interaction.
Biomolecular interaction mechanism of an anticancer drug, pazopanib with human serum albumin: a multi-spectroscopic and computational approach

Kandandapani S, Kabir MZ, Ridzwan NFW, Mohamad SB, Tayyab S

J Biomol Struct Dyn, 2022 Nov;40(18):8312-8323.
PMID: 33870854 DOI: 10.1080/07391102.2021.1911850

Pazopanib (PZP) is a multi-targeting tyrosine kinase inhibitor and is currently approved by FDA for the treatment of soft tissue sarcoma and renal cancer. Molecular interaction mechanism of PZP with human serum albumin (HSA) was explored under simulated physiological conditions (pH = 7.4), using fluorescence and UV absorption spectroscopy along with computational methods. Based on the inverse correlation between the Stern-Volmer constant (Ksv) and temperature, it was concluded that PZP quenched the protein fluorescence through static quenching mechanism. This was also confirmed from the UV-vis absorption spectral results. Moderate binding affinity between PZP and HSA was evident from the Ka values (5.51 - 1.05 × 105 M-1) while PZP-HSA complex formation was driven by hydrophobic and van der Waals interactions as well as hydrogen bonds, as revealed by positive entropy change (ΔS = +98.37 J mol-1 K-1) and negative enthalpy change (ΔH = -60.31 kJ mol-1). Three-dimensional fluorescence spectral results disclosed microenvironmental perturbations around Trp and Tyr residues of the protein upon PZP binding. Interestingly, the addition of PZP to HSA significantly protected the protein against thermal stress. Competitive drug displacement results obtained with warfarin, phenylbutazone and diazepam elucidated Sudlow's Site I, positioned in subdomain IIA of HSA, as the preferred binding site of PZP which was well supported by molecular docking analysis, while molecular dynamics simulation results suggested the stability of the PZP-HSA complex.Communicated by Vsevolod Makeev.
Supramolecular interaction of 6-shogaol, a therapeutic agent of Zingiber officinale with human serum albumin as elucidated by spectroscopic, calorimetric and molecular docking methods

Feroz SR, Mohamad SB, Lee GS, Malek SN, Tayyab S

Phytomedicine, 2015 Jun 01;22(6):621-30.
PMID: 26055127 DOI: 10.1016/j.phymed.2015.03.016

BACKGROUND: 6-Shogaol, one of the main bioactive constituents of Zingiber officinale has been shown to possess various therapeutic properties. Interaction of a therapeutic compound with plasma proteins greatly affects its pharmacokinetic and pharmacodynamic properties.
PURPOSE: The present investigation was undertaken to characterize the interaction between 6-shogaol and the main in vivo transporter, human serum albumin (HSA).
METHODS: Various binding characteristics of 6-shogaol-HSA interaction were studied using fluorescence spectroscopy. Thermal stability of 6-shogaol-HSA system was determined by circular dichroism (CD) and differential scanning calorimetric (DSC) techniques. Identification of the 6-shogaol binding site on HSA was made by competitive drug displacement and molecular docking experiments.
RESULTS: Fluorescence quench titration results revealed the association constant, Ka of 6-shogaol-HSA interaction as 6.29 ± 0.33 × 10(4) M(-1) at 25 ºC. Values of the enthalpy change (-11.76 kJ mol(-1)) and the entropy change (52.52 J mol(-1) K(-1)), obtained for the binding reaction suggested involvement of hydrophobic and van der Waals forces along with hydrogen bonds in the complex formation. Higher thermal stability of HSA was noticed in the presence of 6-shogaol, as revealed by DSC and thermal denaturation profiles. Competitive ligand displacement experiments along with molecular docking results suggested the binding preference of 6-shogaol for Sudlow's site I of HSA.
CONCLUSION: All these results suggest that 6-shogaol binds to Sudlow's site I of HSA through moderate binding affinity and involves hydrophobic and van der Waals forces along with hydrogen bonds.
Deciphering the binding mode and structural perturbations in floxuridine-human serum albumin complexation with spectroscopic, microscopic, and computational techniques

Rehman F, Abubakar M, Ridzwan NFW, Mohamad SB, Abd Halim AA, Tayyab S

Spectrochim Acta A Mol Biomol Spectrosc, 2024 Mar 05;308:123641.
PMID: 38061108 DOI: 10.1016/j.saa.2023.123641

The binding mode of antineoplastic antimetabolite, floxuridine (FUDR), with human serum albumin (HSA), the leading carrier in blood circulation, was ascertained using multi-spectroscopic, microscopic, and computational techniques. A static fluorescence quenching was established due to decreased Ksv values with rising temperatures, suggesting FUDR-HSA complexation. UV-vis absorption spectral results also supported this conclusion. The binding constant, Ka values, were found within 9.7-7.9 × 103 M-1 at 290, 300, and 310 K, demonstrating a moderate binding affinity for the FUDR-HSA system. Thermodynamic data (ΔS = +46.35 J.mol-1.K-1 and ΔH = -8.77 kJ.mol-1) predicted the nature of stabilizing forces (hydrogen-bonds, hydrophobic, and van der Waals interactions) for the FUDR-HSA complex. Circular dichroism spectra displayed a minor disruption in the protein's 2° and 3° structures. At the same time, atomic force microscopy images proved variations in the FUDR-HSA surface morphology, confirming its complex formation. The protein's microenvironment around Trp/Tyr residues was also modified, as judged by 3-D fluorescence spectra. FUDR-bound HSA showed better resistance against thermal stress. As disclosed from ligand displacement studies, the FUDR binding site was placed in subdomain IIA (Site I). Further, the molecular docking analysis corroborated the competing displacement studies. Molecular dynamics evaluations revealed that the complex achieved equilibrium during simulations, confirming the FUDR-HSA complex's stability.
Fulltext Probing the interaction of a therapeutic flavonoid, pinostrobin with human serum albumin: multiple spectroscopic and molecular modeling investigations

Feroz SR, Mohamad SB, Bakri ZS, Malek SN, Tayyab S

PLoS One, 2013;8(10):e76067.
PMID: 24116089 DOI: 10.1371/journal.pone.0076067

Interaction of a pharmacologically important flavonoid, pinostrobin (PS) with the major transport protein of human blood circulation, human serum albumin (HSA) has been examined using a multitude of spectroscopic techniques and molecular docking studies. Analysis of the fluorescence quenching data showed a moderate binding affinity (1.03 × 10(5) M(-1) at 25°C) between PS and HSA with a 1∶1 stoichiometry. Thermodynamic analysis of the binding data (ΔS = +44.06 J mol(-1) K(-1) and ΔH = -15.48 kJ mol(-1)) and molecular simulation results suggested the involvement of hydrophobic and van der Waals forces, as well as hydrogen bonding in the complex formation. Both secondary and tertiary structural perturbations in HSA were observed upon PS binding, as revealed by intrinsic, synchronous, and three-dimensional fluorescence results. Far-UV circular dichroism data revealed increased thermal stability of the protein upon complexation with PS. Competitive drug displacement results suggested the binding site of PS on HSA as Sudlow's site I, located at subdomain IIA, and was well supported by the molecular modelling data.
Fulltext Spectrofluorometric and molecular docking studies on the binding of curcumenol and curcumenone to human serum albumin

Hamdi OA, Feroz SR, Shilpi JA, Anouar el H, Mukarram AK, Mohamad SB, et al.

Int J Mol Sci, 2015;16(3):5180-93.
PMID: 25756376 DOI: 10.3390/ijms16035180

Curcumenol and curcumenone are two major constituents of the plants of medicinally important genus of Curcuma, and often govern the pharmacological effect of these plant extracts. These two compounds, isolated from C. zedoaria rhizomes were studied for their binding to human serum albumin (HSA) using the fluorescence quench titration method. Molecular docking was also performed to get a more detailed insight into their interaction with HSA at the binding site. Additions of these sesquiterpenes to HSA produced significant fluorescence quenching and blue shifts in the emission spectra of HSA. Analysis of the fluorescence data pointed toward moderate binding affinity between the ligands and HSA, with curcumenone showing a relatively higher binding constant (2.46 × 105 M-1) in comparison to curcumenol (1.97 × 104 M-1). Cluster analyses revealed that site I is the preferred binding site for both molecules with a minimum binding energy of -6.77 kcal·mol-1. However, binding of these two molecules to site II cannot be ruled out as the binding energies were found to be -5.72 and -5.74 kcal·mol-1 for curcumenol and curcumenone, respectively. The interactions of both ligands with HSA involved hydrophobic interactions as well as hydrogen bonding.
Exploring nalbuphine loaded chitosan nanoparticles for effective pain management through intranasal administration: a comparative study

Khanna K, Sharma N, Karwasra R, Kumar A, Nishad DK, Janakiraman AK, et al.

J Drug Target, 2024 Sep 04.
PMID: 39229894 DOI: 10.1080/1061186X.2024.2397800

BACKGROUND: Intranasal drug delivery shows potential for brain access via olfactory and trigeminal routes.
PURPOSE: This work aimed to ensure brain availability of nalbuphine via the nasal route.
METHOD: Chitosan based nanoparticles loaded with nalbuphine were successfully prepared using ionic gelation method and characterised.
RESULT: SEM results revealed that the nanoparticles were spherical in shape, with an average size of 192.4 ± 11.6 nm. Zeta potential and entrapment efficiency was found 32.8 mV and 88.43 ± 7.75%, respectively. The X-ray diffractometry and DSC results unravel a profound understanding on the physical and thermal characteristics. The in-vitro release of nalbuphine from the nanoparticles was biphasic, with an initial burst release followed by a slow-release profile. In-vitro cell study on HEK-293 cells and microscopic images of brain tissue confirmed the safety profile of formulation. In-vivo efficacy studies on animal confirmed the effectiveness of developed intranasal formulation as compared to the standard therapy. The in-vivo pharmacokinetic studies showed that the prepared nanoparticles were able to efficiently deliver nalbuphine to the brain in comparison to the other body organs. Gamma scintigraphy images showed retention of the drug in the brain. Furthermore, the efficacy studies confirmed that the nanoparticles were found significantly more effective than the marketed formulation in pain management.
Diabetes and Ramadan: Practical guidelines 2021

Hassanein M, Afandi B, Yakoob Ahmedani M, Mohammad Alamoudi R, Alawadi F, Bajaj HS, et al.

Diabetes Res Clin Pract, 2022 Jan 08.
PMID: 35016991 DOI: 10.1016/j.diabres.2021.109185

Fasting during Ramadan is one of the five pillars of Islam and is obligatory for all healthy Muslims from the age of puberty. Though individuals with some illness and serious medical conditions, including some people with diabetes, can be exempted from fasting, many will fast anyway. It is of paramount importance that people with diabetes that fast are given the appropriate guidance and receive proper care. The International Diabetes Federation (IDF) and Diabetes and Ramadan (DaR) International Alliance have come together to provide a substantial update to the previous guidelines. This update includes key information on fasting during Ramadan with type 1 diabetes, the management of diabetes in people of elderly ages and pregnant women, the effects of Ramadan on one's mental wellbeing, changes to the risk of macrovascular and microvascular complications, and areas of future research. The IDF-DAR Diabetes and Ramadan Practical Guidelines 2021 seek to improve upon the awareness, knowledge and management of diabetes during Ramadan, and to provide real-world recommendations to health professionals and the people with diabetes who choose to fast.