Shevin Rizal Feroz

The prevalence of epilepsy, affecting millions across all age groups, has intensified the need for novel therapeutic interventions. Despite advances in antiseizure medications (ASMs), challenges persist, particularly drug resistance and significant psychiatric and behavioral adverse effects. Isoguvacine (IGV), a potent γ-aminobutyric acid type A receptor agonist, holds promise for epilepsy treatment but suffers from poor blood–brain barrier (BBB) permeability due to its zwitterionic nature. To address this limitation, two ester prodrugs: E7 (heptyl 1,2,3,6-tetrahydropyridine-4-carboxylate) and E14 (tetradecyl 1,2,3,6-tetrahydropyridine-4-carboxylate) were synthesized to enhance BBB penetration and central nervous system (CNS) delivery. This study investigates the interactions of IGV and its derivatives with human serum albumin (HSA), a key plasma transport protein, using a suite of biophysical and computational techniques. UV spectroscopic analysis confirmed protein–ligand complexation, with E7 and E14 exhibiting enhanced binding compared to IGV. Isothermal titration calorimetry revealed that E14 demonstrated superior binding affinity ( K _a = 2.42 × 10 ⁶ M⁻¹) compared to E7 ( K _a = 3.41 × 10 ⁴ M⁻¹), while IGV showed negligible interaction. Atomic force microscopy and circular dichroism spectroscopy indicated that the enhanced hydrophobicity of E7 and E14 promoted stable protein–ligand interactions without perturbing the secondary and tertiary structures of HSA. Molecular docking studies corroborated the superior binding affinity of E14 towards HSA, while molecular dynamics simulations confirmed the enhanced stability of the E14 –HSA complex. These results highlight the potential of E14 as a promising prodrug candidate for CNS-targeted epilepsy therapy and underscore the importance of albumin binding in modulating drug bioavailability and distribution.

Ar-turmerone, a major bioactive compound in Curcuma purpurascens, has been reported to exhibit anti-inflammatory, antiproliferative, antifungal, antioxidant, and anticancer properties. This study investigated its interaction with human serum albumin (HSA) using spectroscopic, microscopic, and computational approaches to characterize its binding properties, which are crucial for its distribution and transport in the bloodstream. Fluorescence spectroscopy showed a 34% decrease in HSA fluorescence intensity at 90 μM ar-turmerone, accompanied by a 2 nm blue shift, suggesting a transition of the protein's fluorophores' microenvironment to a slightly nonpolar state. Binding analysis indicated a moderate binding affinity (K_a = 1.79 ± 0.12 × 10⁴ M^-1) and a negative Gibbs free energy change (ΔG° = -6.03 ± 0.04 kcal/mol), indicating a spontaneous and energetically favorable binding process. Hypochromic effects near the Trp residue suggested a static interaction mechanism. Circular dichroism analysis confirmed that ar-turmerone did not induce major alterations in HSA's secondary and tertiary structures. Microscopic observations revealed slight modifications to the protein surface, suggesting the formation of protein aggregates. Both displacement studies and molecular docking results indicated that ar-turmerone primarily binds at the Site III (subdomain IB) of HSA. Molecular docking further suggested that this binding is stabilized through hydrogen bonding, hydrophobic interactions, and van der Waals forces. These findings provide insights into the binding dynamics of ar-turmerone with HSA, which may influence its transport, stability, and bioavailability. Understanding this interaction is essential for assessing its pharmacokinetic behavior, including transport, stability, bioavailability, which are critical for potential applications in drug delivery and therapeutic development.

Epilepsy is a neurological disorder affecting millions of people worldwide. Antiseizure medications (ASM) remain a critical therapeutic intervention for treating epilepsy, notwithstanding the rapid development of other therapies. There have been substantial advances in epilepsy medications over the past three decades, with over 20 ASMs now available commercially. Here we describe the conventional and unique mechanisms of action of ASMs, focusing on everolimus, cannabidiol, cenobamate, fenfluramine, and ganaxolone, the five most recently marketed ASMs. Major obstacles in the development of ASMs are also addressed, particularly drug-resistant epilepsy as well as psychiatric and behavioral adverse effects of ASMs. Moreover, we delve into the mechanisms and comparative efficacy of ASM polytherapy, with remarks on the benefits and challenges in their application in clinical practice. In addition, the characteristics of the ideal ASM are outlined in this review. The review also discusses the development of new potential ASMs, including modifying existing ASMs to improve efficacy and tolerability. Furthermore, we expound on the modulation of γ- aminobutyric acid type A receptor (GABAAR) as a strategy for the treatment of epilepsy and the identification of a GABAAR agonist, isoguvacine, as a potential ASM.

Mitragynine (MTG), the primary psychoactive alkaloid in Mitragyna speciosa (kratom), has garnered much attention for its therapeutic properties, which is attributed mainly to its selective action on opioid receptors. Despite its clinical potential, the molecular framework of its binding to plasma proteins remains incomplete. Specifically, no studies have thoroughly examined its interaction with α1-acid glycoprotein (AAG), a carrier protein in the circulatory system that influences drug disposition and bioavailability. Hence, this study aims to explore the binding dynamics between MTG and AAG using a combination of spectroscopic, calorimetric, microscopic, and computational methods. Based on isothermal titration calorimetric and fluorescence studies, an intermediate affinity for the MTG-AAG binding was determined (K_a ∼ 10⁵ M^-1). Despite evidence of microenvironmental changes around Trp residues, MTG binding did not disrupt the overall structural integrity of AAG. Thermodynamic analysis indicated that the MTG-AAG interaction was energetically favorable, and enthalpy driven mainly by hydrogen bonding and van der Waals forces, with negative entropy change suggesting a more ordered complex formation. Docking analysis showed MTG embedded more deeply within the central cavity of variant F1*S, enhancing complex stability, as opposed to binding near the cavity entrance in variant A. Molecular dynamics simulations supported the stable complexation of MTG with both AAG variants, with variant F1*S maintaining more structural compactness while variant A exhibited slight unfolding upon binding. These findings have clear significance on the potential therapeutic applications of kratom-derived drugs, especially those structurally related to MTG.

Curcumin, one of the major ingredients of turmeric (Curcuma longa), has been widely reported for its diverse bioactivities, including against malaria and inflammatory-related diseases. However, curcumin’s low bioavailability limits its potential as an antimalarial and anti-inflammatory agent. Therefore, research on the design and synthesis of novel curcumin derivatives is being actively pursued to improve the pharmacokinetic profile and efficacy of curcumin. This review discusses the antimalarial and anti-inflammatory activities and the structure–activity relationship (SAR), as well as the mechanisms of action of curcumin and its derivatives in malarial treatment. This review provides information on the identification of the methoxy phenyl group responsible for the antimalarial activity and the potential sites and functional groups of curcumin for structural modification to improve its antimalarial and anti-inflammatory actions, as well as potential molecular targets of curcumin derivatives in the context of malaria and inflammation.

Dienelactone hydrolase, an α/β hydrolase enzyme, catalyzes the hydrolysis of dienelactone to maleylacetate, an intermediate for the Krebs cycle. Genome sequencing of the psychrophilic yeast, Glaciozyma antarctica predicted a putative open reading frame (ORF) for dienelactone hydrolase (GaDlh) with 52% sequence similarity to that from Coniophora puteana. Phylogenetic tree analysis showed that GaDlh is closely related to other reported dienelactone hydrolases, and distantly related to other α/β hydrolases. Structural prediction using MODELLER 9.14 showed that GaDlh has the same α/β hydrolase fold as other dienelactone hydrolases and esterase/lipase enzymes, with a catalytic triad consisting of Cys–His–Asp and a G–x–C–x–G–G motif. Based on the predicted structure, GaDlh exhibits several characteristics of cold-adapted proteins such as glycine clustering in the binding pocket, reduced protein core hydrophobicity, and the absence of proline residues in loops. The putative ORF was amplified, cloned, and overexpressed in an Escherichia coli expression system. The recombinant protein was overexpressed as soluble proteins and was purified via Ni–NTA affinity chromatography. Biochemical characterization of GaDlh revealed that it has an optimal temperature at 10 °C and that it retained almost 90% of its residual activity when incubated for 90 min at 10 °C. The optimal pH was at pH 8.0 and it was stable between pH 5–9 when incubated for 60 min (more than 50% residual activity). Its K_m value was 256 μM and its catalytic efficiency was 81.7 s⁻¹. To our knowledge, this is the first report describing a novel cold-active dienelactone hydrolase-like protein.