Synthesis, anti-α-glucosidase activity, inhibition interaction, and anti-diabetic activity of novel cryptolepine derivatives

Design and evaluation of curcumin-derived aldopentose compounds: Unlocking their antidiabetic potential through integrative in vitro, in vivo, and in silico studies on carbohydrate-degrading enzymes

Natural polyphenol compounds such as curcumin can inhibit carbohydrate-hydrolyzing enzymes, which may offer an alternative to expensive and potentially side-effect-inducing α-glucosidase inhibitors like acarbose. Hence, this study carried out the synthesis of curcumin aldopentose derivatives, examining their capacity to inhibit the α-glucosidase and α-amylase enzymes with the aim to alleviate hyperglycemia. Initially, the aldopentose derivatives from curcumin were synthesized and confirmed by spectroscopic methods such as MS, 13CNMR, 1HNMR, and FTIR. Afterward, we investigated the inhibitory effects of all derivatives on the α-amylase and α-glucosidase enzymes spectroscopically and determined their inhibition mechanism. We assessed the antioxidant activity and the stability of the synthetic derivatives in the simulated intestinal environment. Finally, we measured the postprandial blood glucose level after administering saturated starch in vivo. The modified compounds showed improved inhibitory effects compared to curcumin alone, with compound C3 demonstrating particularly strong enzyme inhibition. However, when compared with acarbose, a known commercial antidiabetic drug, the synthetic compounds showed lower inhibitory activity against both enzymes, resulting in fewer side effects related to undigested polysaccharides in the gut. Molecular docking studies show introducing a pentose moiety to the curcumin backbone enhanced docking affinities toward both enzymes and subsequently altered the associated IC50 and Ki values. Overall, compound C3 has the potential to be an inhibitor of carbohydrate-degrading enzymes and can effectively reduce glucose absorption in vivo. Given its antioxidant capabilities and reasonable stability, the compound in question shows promises as a potent derivative for the development of new anti-hyperglycemic drugs in future research endeavours.

Inhibition effects of Eucalyptus globules Labill. essential oil against tyrosinase

Essential oils derived from Eucalyptus globules Labill. (EGEOs) represent a significant class of bioactive metabolites with broad applications in medicinal and pharmaceutical industries. Despite their various biological activities, the potential of EGEOs to inhibit tyrosinase, a key enzyme in melanin biosynthesis, remains unexplored. Then, this study delineates the inhibitory effects of EGEOs on tyrosinase. Our findings indicated that EGEOs acted as one reversible and non-competitive inhibitor toward tyrosinase, presenting an inhibition rate of 59.6% (10 mg/ml). Circular dichroism (CD) spectral analysis suggested that EGEOs induced conformational changes in tyrosinase, potentially disrupting its catalytic function. The binding of EGEOs to tyrosinase, as evidenced by ANS binding assays, led to the exposure of hydrophobic regions within the enzyme, further impairing its activity. Molecular docking studies illustrated the specific interactions between the major metabolite of EGEOs, 1,8-cineole, and tyrosinase. Moreover, the impact of EGEOs on melanin production was assessed in B16F10 melanoma cells, demonstrating a significant reduction in intracellular melanin content upon EGEOs treatment. Collectively, these results suggested EGEOs as one promising natural tyrosinase inhibitor with potential applications in treating hyperpigmentation and associated skin disorders.

Inhibition effects of xanthohumol on α-amylase and α-glucosidase: Kinetics, multi-spectral and molecular docking

α-Amylase and α-glucosidase, two therapeutic targets for diabetes management, play crucial roles in carbohydrate metabolism and glucose absorption. Xanthohumol, one chalcone derived from hops, has demonstrated potential as a natural healthy phytonutrient. But its inhibition effects against α-amylase and α-glucosidase were still unclear. This study employs a comprehensive analytical strategy, including kinetics, multi-spectral, and molecular docking methods, to dissect the inhibition effects of xanthohumol against α-amylase and α-glucosidase. Our findings indicated that xanthohumol exerted a reversible mixed-type inhibition on both enzymes, with IC50 values of 71.07 ± 5.82 μM for α-amylase and 32.58 ± 3.11 μM for α-glucosidase. Multi-spectral analyses (fluorescence quenching, synchronous fluorescence, 3D fluorescence, ANS-binding fluorescence, and CD) revealed that xanthohumol binding induced conformation changes and microenvironment alterations in the enzymes, thereby inhibiting their activities. Molecular docking and dynamics studies further substantiated the interaction forces between xanthohumol and the enzymes. This research provided insights into the effects of xanthohumol as an inhibitor of α-amylase and α-glucosidase, offering valuable data to support the development of xanthohumol as a natural therapeutic for diabetes management.

Novel sulfonyl hydrazide based β-carboline derivatives as potential α-glucosidase inhibitors: design, synthesis, and biological evaluation

A series of novel sulfonyl hydrazide based β-carboline derivatives (SX1-SX32) were designed and synthesized, and their structures were characterized on NMR and HRMS. Their α-glucosidase inhibitory screening results found that compounds (SX1-SX32) presented potential α-glucosidase inhibitory: IC50 values being 2.12 ± 0.33-19.37 ± 1.49 μM. Compound SX29 with a para-phenyl (IC50: 2.12 ± 0.33 μM) presented the strongest activity and was confirmed as a noncompetitive inhibitor. Fluorescence spectra, CD spectra and molecular docking were conducted to describe the inhibition mechanism of SX29 against α-glucosidase. Cells cytotoxicity indicated SX29 (0-32 μM) had no cytotoxicity on 293T cells. In particular, in vivo experiments revealed that oral administration of SX29 could regulate hyperglycemia and glucose tolerance of diabetic mice. These achieved findings indicated that sulfonyl hydrazide based β-carboline derivatives bore promising potential for discovering new α-glucosidase inhibitors with hypoglycemic activity.

Synthesis and biological assessment of benzimidazole-acrylonitrile-1,2,3-triazole derivatives as α-glucosidase inhibitors

In the pursuit of developing potent α-glucosidase inhibitors for managing diabetes, a series of novel benzimidazole-acrylonitrile-1,2,3-triazole derivatives were designed. Sixteen derivatives (12a-p) were synthesized by varying substituents on the phenyl ring of the N-phenylacetamide moiety. Among these, compound 12m emerged as highly effective against α-glucosidase, displaying an IC50 value of 6.0 ± 0.2 μM, significantly outperforming the positive control acarbose (IC50 = 752.0 ± 2.0 μM). The kinetic evaluation revealed that 12m acts as a reversible competitive inhibitor with a Ki value of 4.5 µM. Molecular modeling and dynamics simulations underscored favorable binding energies, highlighting interactions of these compounds with critical amino acids within the α-glucosidase active site. These findings position 12m as a promising candidate for the development of α-glucosidase inhibitors with potent anti-diabetic potential.

New benzimidazole-indole-amide derivatives as potent α-glucosidase and acetylcholinesterase inhibitors

New derivatives 6a-m with benzimidazole-indole-amide scaffold were developed, synthesized, and assessed for potential inhibitory effects on α-glucosidase and acetylcholinesterase (AChE). These compounds were synthesized by various amine derivatives. With the exception of two compounds, the α-glucosidase inhibitory activities of the title derivatives were more than that of the positive control acarbose. Moreover, the anti-AChE activity of these compounds, with the exception of one compound, was better than that of tacrine (standard inhibitor). The most potent compound against α-glucosidase was 3-methylphenyl derivative 6i and the most potent compound against AChE was 3,4-dimethoxyphenethyl derivative 6m. All the synthesized compounds were placed in the active sites of α-glucosidase and AChE by in silico docking method and the obtained binding energies were approximately in agreement with the in vitro observed data. Interaction modes of the most potent compounds 6i and 6m demonstrated that these compounds interacted with important residues of their target enzymes. Molecular dynamics simulation was conducted specifically on compound 6i in complex with α-glucosidase to obtain deeper insights into the behavior of this molecule. Furthermore, in silico pharmacokinetic and toxicity studies on the most potent compound predicted that these compounds have good profiles in terms of oral absorption and toxicity.

Design, synthesis, biological evaluations and in silico studies of (Z)-2-(2,4-dioxothiazolidin-5-ylidene)methyl)-2-ethoxyphenyl-alkyl/arylsulfonates as potential α-glucosidase inhibitors

Diabetes mellitus is considered one of the major worldwide health emergencies of the twenty-first century. This work described development, synthesis, and characterization of new (Z)-2-(2,4-dioxothiazolidin-5-ylidene)methyl)-2-ethoxyphenyl-alkyl/aryl-sulfonates. Compounds 7j and 7m were shown to be the most potent among the newly developed (Z)-2-(2,4-dioxothiazolidin-5-ylidene)methyl)-2-ethoxyphenyl-alkyl/aryl-sulfonates after in vitro testing for α-glucosidase inhibitory activity. Following that, an in-vivo disaccharide loading test was performed on these compounds. From the cytotoxicity studies, the most potent substance (7m) was also founded non-toxic. To investigate the binding mechanism and important interactions of α-glucosidase's amino acid residues, docking analyses were completed and binding affinities of the synthesised compounds were observed from -7.1 to 9.6 kcal/mol. To determine the binding stability of the α-glucosidase protein with chemicals 7j and 7m, molecular dynamic simulations were employed. In silico research and prediction studies for absorption, distribution, metabolism, and excretion (ADME) were used to identify the "druggable" pharmacokinetic profiles. In this instance, we developed unique (Z)-2-(2,4-dioxothiazolidin-5-ylidene)methyl)-2-ethoxyphenyl-alkyl/aryl-sulfonates as α-glucosidase inhibitors.

2β-Acetoxyferruginol derivatives as α-glucosidase inhibitors: Synthesis and biological evaluation

To find potential α-glucosidase inhibitors, a series of 2β-acetoxyferuginol derivatives containing cinnamic acid (WXC-1 ∼ 25) were synthesized and investigated their biological activity. All derivatives (WXC-1 ∼ 25) displayed better inhibitory activity (IC50 values: 7.56 ± 1.35 ∼ 25.63 ± 1.72 μM) compared to acarbose (IC50 vaule: 564.28 ± 48.68 μM). In particularly, WXC-25 with 4-hydroxycinnamic acid section showed the best inhibitory activity (IC50 vaule: 2.02 ± 0.14 μM), ∼75-fold stronger than acarbose. Kinetics results suggested WXC-25 being one reversible non-competition inhibitors. Fluorescence quenching results indicated that WXC-25 quenched the fluorescence of α-glucosidase in a static manner. 3D fluorescence spectra results indicated that WXC-25 treatment could cause the conformation changes of α-glucosidase. Moreover, molecular docking simulated the detailed interaction of WXC25 with α-glucosidase.

Insights into inhibitory action and interaction of bisdemethoxycurcumin on tyrosinase: Spectroscopic and docking analysis

Bisdemethoxycurcumin (BDMC), a demethoxy derivative of curcumin, has garnered interest for its potential anti-tyrosinase properties, which are crucial for applications in food preservation and cosmetic industries. Despite its recognized bioactive effects, the detailed inhibitory action and interaction of BDMC on tyrosinase and its application in anti-browning processes remain unclear. This study aims to dissect the molecular interactions of BDMC with tyrosinase, elucidate its inhibition mechanism, and assess its efficacy in preventing browning, thereby underpinning its potential as a natural anti-browning agent. Employing a battery of spectroscopic techniques, we characterized the interaction of BDMC with tyrosinase. The anti-browning properties of BDMC were evaluated on fresh-cut apples, and its effect on enzymatic activities related to browning was also investigated. The results indicate that BDMC interacts with tyrosinase in a reversible mixed-type inhibition manner with an IC50 value of 12.5 ± 0.2 μM. Surface Plasmon Resonance (SPR) results indicated that BDMC presented good binding affinity toward tyrosinase. Fluorescence quenching results showed that BDMC could quench the fluorescence of tyrosinase in a static process. Synchronous fluorescence, circular dichroism spectra, and three-dimensional fluorescence results indicated that interaction of BDMC against tyrosinase resulted in changes of tyrosinase on microenvironment and conformation, thus causing decrease of tyrosinase activity. Copper-chelating results presented that BDMC could chelate to copper with stoichiometric ratio of 1: 2. Molecular docking provided intricate details of how BDMC interacted with tyrosinase. Moreover, BDMC exhibited anti-browning capability on fresh cut apples, and could regulate PPO, POD, and APX activities. The comprehensive analysis proposed in this study consolidated the theoretical basis of BDMC as a tyrosinase inhibitor and supported its potential anti-browning application.

Design, synthesis, biological evaluation, kinetic studies and molecular modeling of imidazo-isoxazole derivatives targeting both α-amylase and α-glucosidase inhibitors

Herein, a novel set of imidazo-isoxazole derivatives containing thiourea and urea scaffolds were synthesized, characterized (1H NMR, 13C NMR, and elemental analysis). These compounds were biologically evaluated for their α-amylase and α-glucosidase inhibitory activity, identifying 5f as the most active (IC50 26.67 ± 1.25 μM and 39.12 ± 1.83 μM against α-amylase α-glucosidase, respectively), better than the standard, acarbose. Enzymatic kinetic results showed that 5f and acarbose complete competitive type inhibitors. The structure-activity relationship (SAR) demonstrated that undergoing substitutions on R1 and R2 groups attached to the thiourea/urea moiety chains controlled the activity. Besides, in-silico ADMET study showed that almost title compounds exhibited satisfactory pharmacokinetic properties. In molecular docking study, the top performing compound (5f) exhibited higher binding energies (-5.501 and -6.414 kcal/mol, respectively) showing crucial interactions and that snuggly fit in their active site. To shed light on their mechanism of action, molecular dynamic (MD) simulations approach executed at 100 ns duration authenticated the high stability of 5f-1B2Y and 5f-3A4A complexes. The results of this investigation disclosed that compound 5f may serve as a potential lead, accomplished with in vivo studies, for the management of diabetes.

Development, biological evaluation, and molecular modelling of some benzene-sulfonamide derivatives as protein tyrosine phosphatase-1B inhibitors for managing diabetes mellitus and associated metabolic disorders

Exploring new inhibitors with good bioavailability and high selectivity for managing type 2 diabetes mellitus (T2DM) and its associated complications is a major challenge for research, academia, and the pharmaceutical industry. Protein tyrosine phosphatase-1B (PTP1B) arose as an important negative regulator in insulin signaling pathways associated with metabolic disorders, including T2DM and obesity. Novel neutral compounds with a benzene-sulfonamide scaffold were designed and synthesized based on structural- and ligand-based drug design strategies for fragment growth. Promising hits against PTP1B were identified through in vitro enzymology inhibition assay. Mechanistic aspects of the compound's different inhibition activities were rigorously investigated through molecular docking coupled with explicit dynamics simulations. Four identified hits, 3c, 8, 10a, and 11, with sub-micromolar PTP-1B IC50 and significant predicted pharmacokinetic and pharmacodynamic parameters, were further biologically evaluated for their anti-diabetic, anti-obesity, anti-inflammatory, and anti-oxidant effects in a high-fat diet (HFD) + streptozotocin (STZ)-induced T2DM rat model. All these hit compounds exhibited a significant anti-diabetic and anti-obesity effect and a significant efficacy in reducing oxidative stress and increasing anti-oxidant enzymes while reducing inflammatory markers. Improving compound potency was further highlighted by improving the pharmacokinetic profile of the most active compound, 10a, through nano formulation. Compound 10a nano formulation showed the most promising anti-diabetic and anti-obesity effects and a remarkable histopathological improvement in all organs studied.

Breaking boundaries in diabetic nephropathy treatment: design and synthesis of novel steroidal SGLT2 inhibitors

The activity of sodium glucose co-transporter 2 (SGLT2) has always been an important parameter influencing chronic kidney disease in type-2 diabetic patients. Herein, we have meticulously designed, synthesized, and evaluated several novel steroidal pyrimidine molecules that possess the capability to successfully bind to the SGLT2 protein and inhibit its activity, thereby remedying kidney-related ailments in diabetic patients. The lead steroidal pyrimidine compounds were selected after virtually screening from a library of probable N-heterocyclic steroidal scaffolds. A nano-catalyzed synthetic route was also explored for the synthesis of the steroidal pyrimidine analogs demonstrating an environmentally benign protocol. Extensive in vitro investigations encompassing SGLT2 screening assays and cell viability assessments were conducted on the synthesized compounds. Among the steroidal pyrimidine derivatives evaluated, compound 9a exhibited the highest SGLT2 inhibition activity and underwent further scrutiny. Western blot analysis was employed to determine the impact of 9a on inflammatory and fibrotic proteins, aiming to elucidate its mechanism of action. Additionally, in silico analyses were performed to illuminate the structural dynamics and molecular interaction mechanism of 9a. The overall investigation is crucial for advancing the development of the next generation of anti-diabetic drugs.

Rosa × damascena Herrm. essential oil: anti-tyrosinase activity and phytochemical composition

Tyrosinase is a key enzyme in melanin synthesis, and its natural inhibitors are receiving increasing attention. Rosa × damascena Herrm. essential oil (RDEO), as important functional metabolites, was widely known due to its biological activities. But its tyrosinase inhibitory activity has not been detailed investigated. Therefore, in this paper, RDEO was comprehensively investigated the tyrosinase inhibitory, followed by the phytochemical composition analysis. Activity screening results showed that RDEO exhibited effective anti-tyrosinase activity and was a reversible and mixed-type inhibitor. CD assay results revealed that RDEO could affect the conformation of tyrosinase to reduce the activity. In B16F10 cells, RDEO (25-100 μg/mL) could inhibit intracellular tyrosinase activity and decrease melanin content. Finally, GC-MS analysis of RDEO found that citronellol (21.22%), geraniol (14.1%), eicosane (11.03%), heneicosane (6.65%) and 1-nonadecene (5.16%) were its main phytochemical compositions. This study provided data support for Rosa × damascena Herrm. essential oil as one potential natural tyrosinase inhibitor and its applications in cosmetics and medicine.

Novel thiosemicarbazide-based β-carboline derivatives as α-glucosidase inhibitors: Synthesis and biological evaluation

In the quest for potent α-glucosidase inhibitors to combat diabetes, a series of novel thiosemicarbazide-based β-carboline derivatives (CTL1∼36) were synthesized and evaluated. CTL1∼36 exhibited remarkable inhibitory effects against α-glucosidase, with IC50 values ranging from 2.81 to 12.40 μM, significantly surpassing the positive control acarbose (IC50 = 564.28 μM). Notably, CTL26 demonstrated the most potent inhibition (IC50 = 2.81 μM) and was characterized as a non-competitive inhibitor. Through a combination assay with fluorescence quenching, 3D fluorescence spectra, CD spectra, and molecular docking, we elucidated that CTL26 formed a complex with α-glucosidase via hydrogen bondings and hydrophobic interactions, leading to α-glucosidase conformation changes that impaired enzymatic activity. In vivo studies revealed that oral administration of CTL26 (25 and 50 mg/kg/d) reduced fasting blood glucose levels, enhanced glucose tolerance, and ameliorated lipid abnormalities in diabetic mice. These findings positioned CTL26 as a promising candidate for the development of α-glucosidase inhibitors with anti-diabetic potential.

Honokiol as an α-glucosidase inhibitor

Honokiol, a naturally occurring compound from Magnolia obovata Thunb., has many biological activities, but its anti-α-glucosidase activity is still unclear. Therefore, we determined its inhibitory effects against α-glucosidase. Activity assays showed that honokiol was a reversible mixed-type inhibitor of α-glucosidase, and its IC50 value was 317.11 ± 12.86 μM. Fluorescence results indicated that the binding of honokiol to α-glucosidase caused a reduction in α-glucosidase activity. 3D fluorescence and CD spectra results indicated that the binding of honokiol to α-glucosidase caused conformational change in α-glucosidase. Docking simulated the detailed interactions between honokiol and α-glucosidase, including hydrogen and hydrophobic bonds. All findings showed that honokiol could be used as a natural inhibitor to develop α-glucosidase agents.

Inhibition mechanism investigation of quercetagetin as a potential tyrosinase inhibitor

Tyrosinase is one important rate limiting enzyme in melanin synthesis, directly affecting the melanin synthesis. Quercetagetin is one active ingredient from marigold. Thence, the inhibition effects of quercetagetin against tyrosinase were investigated. The results showed quercetagetin could inhibit tyrosinase activity with IC50 value of 0.19 ± 0.01 mM and the inhibition type was a reversible mixed-type. Results of fluorescence quenching showed quercetagetin could quench tyrosinase fluorescence in static process. CD and 3D fluorescence results showed the interaction of quercetagetin to tyrosinase could change tyrosinase conformation to inhibit activity. Moreover, docking revealed details of quercetagetin's interactions with tyrosinase.