(-)-Kusunokinin as a Potential Aldose Reductase Inhibitor: Equivalency Observed via AKR1B1 Dynamics Simulation

GC-MS fingerprinting, nutritional composition, in vitro pharmacological activities and molecular docking studies of Piper chaba from Uttarakhand region

This study aimed to evaluate the potential therapeutic effects of Piper chaba (PC) growing in the northern region of India, having differences in the phytochemicals, nutritional content, antimicrobial and antioxidant properties by reducing power assay (RPA), 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, phosphomolybdate assay, and antidiabetic potential by α-amylase assay with change in the geographical location. Outcomes of the gas chromatography-mass spectrometry (GC-MS) analysis revealed that phytochemicals such as piperine (46.69%), kusunokinin (8.9%), and sitostenone (7.57%) are the prominent compounds found in PC. The plant has also shown a good nutritional value, i.e., iron (11.25 mg), calcium (147 mg), and vitamin C (9.30 mg) per 100 g. PC has a higher phenolic content than other species (⁓ 13.75 g/100 g plant powder). Among the four tested bacterial strains, the extract is best responsive toward Escherichia coli (35 ± 0.68 mm) which is more than the standard ciprofloxacin (24 ± 0.8 mm). Similarly, among two tested fungal strains, Saccharomyces cerevisiae shows the best zone of inhibition (ZOI) (27.5 ± 0.8 mm), which is greater than tat of standard amphotericin (20.25 ± 0.28 mm). The DDPH method demonstrated the highest antioxidant activity (⁓ 42.61 ± 1.82 µg/ml). IC50 for the antidiabetic potential of PC was found to be 23.09 ± 0.3 µg/ml against α-amylase assay. A molecular docking study revealed that three compounds, piperine, sitostenone and kusunokinin, showed strong binding affinity toward bacterial tyrosyl-tRNA synthetases, fungal dihydrofolate reductase, and α-amylase, respectively. Therefore, the findings of the current study indicate that PC can be considered as a source of food and medicines, either in the form of traditional preparations or as pure active constituents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03996-7.

Role of CSF1R 550th-tryptophan in kusunokinin and CSF1R inhibitor binding and ligand-induced structural effect

Binding affinity is an important factor in drug design to improve drug-target selectivity and specificity. In this study, in silico techniques based on molecular docking followed by molecular dynamics (MD) simulations were utilized to identify the key residue(s) for CSF1R binding affinity among 14 pan-tyrosine kinase inhibitors and 15 CSF1R-specific inhibitors. We found tryptophan at position 550 (W550) on the CSF1R binding site interacted with the inhibitors' aromatic ring in a π-π way that made the ligands better at binding. Upon W550-Alanine substitution (W550A), the binding affinity of trans-(-)-kusunokinin and imatinib to CSF1R was significantly decreased. However, in terms of structural features, W550 did not significantly affect overall CSF1R structure, but provided destabilizing effect upon mutation. The W550A also did not either cause ligand to change its binding site or conformational changes due to ligand binding. As a result of our findings, the π-π interaction with W550's aromatic ring could be still the choice for increasing binding affinity to CSF1R. Nevertheless, our study showed that the increasing binding to W550 of the design ligand may not ensure CSF1R specificity and inhibition since W550-ligand bound state did not induce significantly conformational change into inactive state.

Trans-(±)-TTPG-B Attenuates Cell Cycle Progression and Inhibits Cell Proliferation on Cholangiocarcinoma Cells

This research aimed to determine the target protein and molecular mechanism of trans-(±)-kusunokinin ((±)-KU) derivatives (trans-(±)-ARC and trans-(±)-TTPG-B). Molecular docking was used to predict potential synthesized (±)-KU targets among 22 proteins. The (±)-TTPG-B bound HSP90α better than EC44, native (±)-KU and (-)-KU, and (±)-KU and (-)-ARC. In contrast, (-)-ARC bound PI3K more strongly than any other test compound. CSF1R and AKR1B1 were not supposed to be the target of (±)-TTPG-B and (±)-ARC, unlike native (±)-KU. The (±)-TTPG-B bound Tyr139 and Trp162 of HSP90α. Moreover, (-)-ARC bound PI3K via hydrogen bonds and π-π stacking at distinct amino acids, which was different from the other tested compounds. Using half of the IC50 concentration, (±)-TTPG-B, (±)-KU and (±)-ARC enhanced cell cycle arrest at the G0/G1 phase after 12 h and 24 h on KKU-M213 (CCA) cells. The (±)-TTPG-B showed a stronger inhibitory effect than (±)-ARC and (±)-KU on HSP90α, PI3K, HSP90β, c-Myc, AKT, MEK1, CyclinB1, CyclinD1, and CDK1 for 24 and 48 h after treatment with the same concentration (0.015 µM). Thus, trans-(±)-TTPG-B, a newly synthesized compound, has pharmacological potential for development as a target therapy for CCA treatment.

Novel Lawsone-Quinoxaline Hybrids as New Dual Binding Site Acetylcholinesterase Inhibitors

A new family of lawsone-quinoxaline hybrids was designed, synthesized, and evaluated as dual binding site cholinesterase inhibitors (ChEIs). In vitro tests revealed that compound 6d was the most potent AChEI (IC50 = 20 nM) and BChEI (IC50 = 220 nM). The compound 6d did not show cytotoxicity against the SH-SY5Y neuronal cells (GI50 > 100 μM). In silico and enzyme kinetic experiments demonstrated that compound 6d bound to both the catalytic anionic site and the peripheral anionic site of HuAChE. The lawsone-quinoxaline hybrids exhibited potential for further development of potent acetylcholinesterase inhibitors for the treatment of Alzheimer's disease.

Computational model for lipid binding regions in phospholipase (Ves a 1) from Vespa venom

The Thai banded tiger wasp (Vespa affinis) is a dangerous vespid species found in Southeast Asia, and its stings often result in fatalities due to the presence of lethal phospholipase A[Formula: see text], known as Vespapase or Ves a 1. Developing anti-venoms for Ves a 1 using chemical drugs, such as chemical drug guide, remains a challenging task. In this study, we screened 2056 drugs against the opening conformation of the venom using the ZINC 15 and e-Drug 3D databases. The binding free energy of the top five drug candidates complexed with Ves a 1 was calculated using 300-ns-MD trajectories. Our results revealed that voxilaprevir had a higher binding free energy at the catalytic sites than other drug candidates. Furthermore, the MD simulation results indicated that voxilaprevir formed stable conformations within the catalytic pocket. Consequently, voxilaprevir could act as a potent inhibitor, opening up avenues for the development of more effective anti-venom therapeutics for Ves a 1.

Anticancer Activity of (±)-Kusunokinin Derivatives towards Cholangiocarcinoma Cells

This study aimed to investigate the cytotoxicity and anticancer activity of (±)-kusunokinin derivatives ((±)-TTPG-A and (±)-TTPG-B). The cytotoxicity effect was performed on human cancer cells, including breast cancer, cholangiocarcinoma, colon and ovarian cancer-cells, compared with normal cells, using the MTT assay. Cell-cycle arrest and apoptosis were detected using flow-cytometry analysis. We found that (±)-TTPG-B exhibited the strongest cytotoxicity on aggressive breast-cancer (MDA-MB-468 and MDA-MB-231) and cholangiocarcinoma (KKU-M213), with an IC50 value of 0.43 ± 0.01, 1.83 ± 0.04 and 0.01 ± 0.001 µM, respectively. Interestingly, (±)-TTPG-A and (±)-TTPG-B exhibited less toxicity than (±)-kusunokinin (9.75 ± 0.39 µM) on L-929 cells (normal fibroblasts). Moreover, (±)-TTPG-A predominated the ell-cycle arrest at the S phase, while (±)-TTPG-B caused cell arrest at the G0/G1 phase, in the same way as (±)-kusunokinin in KKU-M213 cells. Both (±)-TTPG-A and (±)-TTPG-B induced apoptosis and multi-caspase activity more than (±)-kusunokinin. Taken together, we conclude that (±)-TTPG-A and (±)-TTPG-B have a strong anticancer effect on cholangiocarcinoma. Moreover, (±)-TTPG-B could be a potential candidate compound for breast cancer and cholangiocarcinoma in the future.

Trans-(±)-Kusunokinin Binding to AKR1B1 Inhibits Oxidative Stress and Proteins Involved in Migration in Aggressive Breast Cancer

Synthetic trans-(±)-kusunokinin ((±)KU), a potential anticancer substance, was revealed to have an inhibitory effect on breast cancer. According to the computational modeling prediction, AKR1B1, an oxidative stress and cancer migration protein, could be a target protein of trans-(-)-kusunokinin. In this study, we determined the binding of (±)KU and AKR1B1 on triple-negative breast and non-serous ovarian cancers. We found that (±)KU exhibited a cytotoxic effect that was significantly stronger than zopolrestat (ZP) and epalrestat (EP) (known AKR1B1 inhibitors) on breast and ovarian cancer cells. (±)KU inhibited aldose reductase activity that was stronger than trans-(-)-arctiin ((-)AR) but weaker than ZP and EP. Interestingly, (±)KU stabilized AKR1B1 on SKOV3 and Hs578T cells after being heated at 60 and 75 °C, respectively. (±)KU decreased malondialdehyde (MDA), an oxidative stress marker, on Hs578T cells in a dose-dependent manner and the suppression was stronger than EP. Furthermore, (±)KU downregulated AKR1B1 and its downstream proteins, including PKC-δ, NF-κB, AKT, Nrf2, COX2, Twist2 and N-cadherin and up-regulated E-cadherin. (±)KU showed an inhibitory effect on AKR1B1 and its downstream proteins, similar to siRNA-AKR1B1. Interestingly, the combination of siRNA-AKR1B1 with EP or (±)KU showed a greater effect on the suppression of AKR1B1, N-cadherin, E-cadherin and NF-κB than single treatments. Taken together, we concluded that (±)KU-bound AKR1B1 leads to the attenuation of cellular oxidative stress, as well as the aggressiveness of breast cancer cell migration.

Phyto-Computational Intervention of Diabetes Mellitus at Multiple Stages Using Isoeugenol from Ocimum tenuiflorum: A Combination of Pharmacokinetics and Molecular Modelling Approaches

In the present study, the anti-diabetic potential of Ocimum tenuiflorum was investigated using computational techniques for α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages. It aimed to elucidate the mechanism by which phytocompounds of O. tenuiflorum treat diabetes mellitus using concepts of druglikeness and pharmacokinetics, molecular docking simulations, molecular dynamics simulations, and binding free energy studies. Isoeugenol is a phenylpropene, propenyl-substituted guaiacol found in the essential oils of plants. During molecular docking modelling, isoeugenol was found to inhibit all the target enzymes, with a higher binding efficiency than standard drugs. Furthermore, molecular dynamic experiments revealed that isoeugenol was more stable in the binding pockets than the standard drugs used. Since our aim was to discover a single lead molecule with a higher binding efficiency and stability, isoeugenol was selected. In this context, our study stands in contrast to other computational studies that report on more than one compound, making it difficult to offer further analyses. To summarize, we recommend isoeugenol as a potential widely employed lead inhibitor of α-glucosidase, α-amylase, aldose reductase, and glycation based on the results of our in silico studies, therefore revealing a novel phytocompound for the effective treatment of hyperglycemia and diabetes mellitus.

Multiprotein Inhibitory Effect of Dietary Polyphenol Rutin from Whole Green Jackfruit Flour Targeting Different Stages of Diabetes Mellitus: Defining a Bio-Computational Stratagem

The anti-diabetic potential of whole unripe jackfruit (peel with pulp, flake, and seed) was investigated using inhibitory assays for α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages. Using activity-guided repeated fractionation on a silica gel column chromatography, dietary flavonoid rutin with potent antihyperglycemic activity was extracted from the methanol extract of whole jackfruit flour (MJ). Rutin was found to inhibit both α-glucosidase (IC50: 7.86 µg/mL) and α-amylase (IC50: 22.00 µg/mL) in a competitive manner of inhibition with low Ki values. In addition, in vitro glycation experiments revealed that rutin prevented each stage of protein glycation as well as the production of intermediate molecules. Furthermore, rutin significantly inhibited aldose reductase (IC50: 2.75 µg/mL) in a non-competitive manner. During in silico studies, molecular docking and molecular dynamics simulation studies have suggested that rutin has a high binding affinity for the enzymes studied, which could explain its inhibitory effects. Rutin interacted with the key residues of the target enzymes’ inhibitor binding sites. Compared to the controls used, rutin had a higher binding efficiency as well as stability in the inhibitor binding pocket of the target enzymes. According to our findings, the presence of rutin is more likely to be associated with the potential of MJ in antihyperglycemic activity via inhibition of α-glucosidase and in anti-diabetic action via inhibition of the polyol pathway and protein glycation. The bio-computational study indicates rutin as a potential lead inhibitor of all the target enzymes used and could be used as an effective anti-diabetic drug in the near future.

Potential Stereoselective Binding of Trans-(±)-Kusunokinin and Cis-(±)-Kusunokinin Isomers to CSF1R

Breast cancer cell proliferation and migration are inhibited by naturally extracted trans-(−)-kusunokinin. However, three additional enantiomers of kusunokinin have yet to be investigated: trans-(+)-kusunokinin, cis-(−)-isomer and cis-(+)-isomer. According to the results of molecular docking studies of kusunokinin isomers on 60 breast cancer-related proteins, trans-(−)-kusunokinin was the most preferable and active component of the trans-racemic mixture. Trans-(−)-kusunokinin targeted proteins involved in cell growth and proliferation, whereas the cis-(+)-isomer targeted proteins involved in metastasis. Trans-(−)-kusunokinin targeted CSF1R specifically, whereas trans-(+)-kusunokinin and both cis-isomers may have bound AKR1B1. Interestingly, the compound’s stereoisomeric effect may influence protein selectivity. CSF1R preferred trans-(−)-kusunokinin over trans-(+)-kusunokinin because the binding pocket required a ligand planar arrangement to form a π-π interaction with a selective Trp550. Because of its large binding pocket, EGFR exhibited no stereoselectivity. MD simulation revealed that trans-(−)-kusunokinin, trans-(+)-kusunokinin and pexidartinib bound CSF1R differently. Pexidartinib had the highest binding affinity, followed by trans-(−)-kusunokinin and trans-(+)-kusunokinin, respectively. The trans-(−)-kusunokinin-CSF1R complex was found to be stable, whereas trans-(+)-kusunokinin was not. Trans-(±)-kusunokinin, a potential racemic compound, could be developed as a selective CSF1R inhibitor when combined.

In Silico Identification of Potential Sites for a Plastic-Degrading Enzyme by a Reverse Screening through the Protein Sequence Space and Molecular Dynamics Simulations

The accumulation of polyethylene terephthalate (PET) seriously harms the environment because of its high resistance to degradation. The recent discovery of the bacteria-secreted biodegradation enzyme, PETase, sheds light on PET recycling; however, the degradation efficiency is far from practical use. Here, in silico alanine scanning mutagenesis (ASM) and site-saturation mutagenesis (SSM) were employed to construct the protein sequence space from binding energy of the PETase–PET interaction to identify the number and position of mutation sites and their appropriate side-chain properties that could improve the PETase–PET interaction. The binding mechanisms of the potential PETase variant were investigated through atomistic molecular dynamics simulations. The results show that up to two mutation sites of PETase are preferable for use in protein engineering to enhance the PETase activity, and the proper side chain property depends on the mutation sites. The predicted variants agree well with prior experimental studies. Particularly, the PETase variants with S238C or Q119F could be a potential candidate for improving PETase. Our combination of in silico ASM and SSM could serve as an alternative protocol for protein engineering because of its simplicity and reliability. In addition, our findings could lead to PETase improvement, offering an important contribution towards a sustainable future.

Inhibitory Effect of Polyphenols from the Whole Green Jackfruit Flour against α-Glucosidase, α-Amylase, Aldose Reductase and Glycation at Multiple Stages and Their Interaction: Inhibition Kinetics and Molecular Simulations

For the first time, α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages inhibitory assays were used to explore the antidiabetic potential of whole unripe jackfruit (peel with pulp, flake, and seed). Two polyphenols (phenolic acids) with strong antihyperglycaemic activity were isolated from the methanol extract of whole jackfruit flour (MJ) using activity-guided repeated fractionation on a silica gel column chromatography. The bioactive compounds isolated were identified as 3-(3,4-Dihydroxyphenyl)-2-propenoic acid (caffeic acid: CA) and 4-Hydroxy-3,5-dimethoxybenzoic acid (syringic acid: SA) after various physicochemical and spectroscopic investigations. CA (IC₅₀: 8.0 and 26.90 µg/mL) and SA (IC₅₀: 7.5 and 25.25 µg/mL) were identified to inhibit α-glucosidase and α-amylase in a competitive manner with low Ki values. In vitro glycation experiments further revealed that MJ and its components inhibited each stage of protein glycation as well as the generation of intermediate chemicals. Furthermore, CA (IC₅₀: 3.10) and SA (IC₅₀: 3.0 µg/mL) inhibited aldose reductase effectively in a non-competitive manner, respectively. The binding affinity of these substances towards the enzymes examined has been proposed by molecular docking and molecular dynamics simulation studies, which may explain their inhibitory activities. The found potential of MJ in antihyperglycaemic activity via inhibition of α-glucosidase and in antidiabetic action via inhibition of the polyol pathway and protein glycation is more likely to be related to the presence of the phenolic compounds, according to our findings.

Effects of trans-(±)-kusunokinin on chemosensitive and chemoresistant ovarian cancer cells

Ovarian cancer ranks eighth in cancer incidence and mortality among women worldwide. Cisplatin-based chemotherapy is commonly used for patients with ovarian cancer. However, the clinical efficacy of cisplatin is limited due to the occurrence of adverse side effects and development of cancer chemoresistance during treatment. Trans-(±)-kusunokinin has been previously reported to inhibit cell proliferation and induce cell apoptosis in various cancer cell types, including breast, colon and cholangiocarcinoma. However, the potential effects of (±)-kusunokinin on ovarian cancer remains unknown. In the present study, chemosensitive ovarian cancer cell line A2780 and chemoresistant ovarian cancer cell lines A2780cis, SKOV-3 and OVCAR-3 were treated with trans-(±)-kusunokinin to investigate its potential effects. MTT, colony formation, apoptosis and multi-caspase assays were used to determine cytotoxicity, the ability of single cells to form colonies, induction of apoptosis and multi-caspase activity, respectively. Moreover, western blot analysis was performed to determine the proteins level of topoisomerase II, cyclin D1, CDK1, Bax and p53-upregulated modulator of apoptosis (PUMA). The results demonstrated that trans-(±)-kusunokinin exhibited the strongest cytotoxicity against A2780cis cells with an IC₅₀ value of 3.4 µM whilst also reducing the colony formation of A2780 and A2780cis cells. Trans-(±)-kusunokinin also induced the cells to undergo apoptosis and increased multi-caspase activity in A2780 and A2780cis cells. This compound significantly downregulated topoisomerase II, cyclin D1 and CDK1 expression, but upregulated Bax and PUMA expression in both A2780 and A2780cis cells. In conclusion, trans-(±)-kusunokinin suppressed ovarian cancer cells through the inhibition of colony formation, cell proliferation and the induction of apoptosis. This pure compound could be a potential targeted therapy for ovarian cancer treatment in the future. However, studies in an animal model and clinical trial need to be performed to support the efficacy and safety of this new treatment.

Synthesis, Biological Evaluation, and In Silico Studies of New Acetylcholinesterase Inhibitors Based on Quinoxaline Scaffold

A quinoxaline scaffold exhibits various bioactivities in pharmacotherapeutic interests. In this research, twelve quinoxaline derivatives were synthesized and evaluated as new acetylcholinesterase inhibitors. We found all compounds showed potent inhibitory activity against acetylcholinesterase (AChE) with IC50 values of 0.077 to 50.080 µM, along with promising predicted drug-likeness and blood-brain barrier (BBB) permeation. In addition, potent butyrylcholinesterase (BChE) inhibitory activity with IC50 values of 14.91 to 60.95 µM was observed in some compounds. Enzyme kinetic study revealed the most potent compound (6c) as a mixed-type AChE inhibitor. No cytotoxicity from the quinoxaline derivatives was noticed in the human neuroblastoma cell line (SHSY5Y). In silico study suggested the compounds preferred the peripheral anionic site (PAS) to the catalytic anionic site (CAS), which was different from AChE inhibitors (tacrine and galanthamine). We had proposed the molecular design guided for quinoxaline derivatives targeting the PAS site. Therefore, the quinoxaline derivatives could offer the lead for the newly developed candidate as potential acetylcholinesterase inhibitors.

Trans-(-)-Kusunokinin: A Potential Anticancer Lignan Compound against HER2 in Breast Cancer Cell Lines?

Trans-(−)-kusunokinin, an anticancer compound, binds CSF1R with low affinity in breast cancer cells. Therefore, finding an additional possible target of trans-(−)-kusunokinin remains of importance for further development. Here, a computational study was completed followed by indirect proof of specific target proteins using small interfering RNA (siRNA). Ten proteins in breast cancer were selected for molecular docking and molecular dynamics simulation. A preferred active form in racemic trans-(±)-kusunokinin was trans-(−)-kusunokinin, which had stronger binding energy on HER2 trans-(+)-kusunokinin; however, it was weaker than the designed HER inhibitors (03Q and neratinib). Predictively, trans-(−)-kusunokinin bound HER2 similarly to a reversible HER2 inhibitor. We then verified the action of (±)-kusunokinin compared with neratinibon breast cancer cells (MCF-7). (±)-Kusunokinin exhibited less cytotoxicity on normal L-929 and MCF-7 than neratinib. (±)-Kusunokinin and neratinib had stronger inhibited cell proliferation than siRNA-HER2. Moreover, (±)-kusunokinin decreased Ras, ERK, CyclinB1, CyclinD and CDK1. Meanwhile, neratinib downregulated HER, MEK1, ERK, c-Myc, CyclinB1, CyclinD and CDK1. Knocking down HER2 downregulated only HER2. siRNA-HER2 combination with (±)-kusunokinin suppressed HER2, c-Myc, CyclinB1, CyclinD and CDK1. On the other hand, siRNA-HER2 combination with neratinib increased HER2, MEK1, ERK, c-Myc, CyclinB1, CyclinD and CDK1 to normal levels. We conclude that trans-(±)-kusunokinin may bind HER2 with low affinity and had a different action from neratinib.

Potency of bisresorcinol from Heliciopsis terminalis on skin aging: in vitro bioactivities and molecular interactions

Background

A bisresorcinol was isolated as the main constituent of Heliciopsis terminalis’s trunk (Proteaceae). Recently, resorcinol is applied as an active whitening agent in various cosmetic products. Because of the structural mimic to resorcinol, benefits of the bisresorcinol as an aging-enzyme antagonist were demonstrated in this study.

Methods

The bisresorcinol was purified from the crude ethanolic extract of H. terminalis’s trunk by solvent extraction and preparative chromatography, respectively. Inhibitory activity on collagenase, elastase, and tyrosinase of the compound was investigated by using a different spectroscopic technique. Molecular docking was carried out to predict possible interactions of the substance around the enzyme active sites.

Results

The IC₅₀ values on collagenase of the bisresorcinol and caffeic acid were 156.7 ± 0.7 and 308.9 ± 1.6 µmole L⁻¹, respectively. For elastase activity, the IC₅₀ of 33.2 ± 0.5 and 34.3 ± 0.3 µmole L⁻¹ was respectively determined for the bisresorcinol and ursolic acid. The bisresorcinol was inhibitory to tyrosinase by exhibiting the IC₅₀ of 22.8 µmole L⁻¹, and that of 78.4 µmole L⁻¹ was present for β-arbutin. The bisresorcinol bound to collagenase, elastase, and tyrosinase with the respective binding energies of −5.89, −5.69, and −6.57 kcal mol⁻¹. These binding energies were in the same ranges of tested inhibitors. The aromatic phenol groups in the structure were responsible for principle as well as supporting binding interactions with enzymes. Hydrogen binding due to hydroxyl groups and π-related attractive forces from an aromatic ring(s) provided binding versatility to bisresorcinol.

Conclusion

The bisresorcinol purified from H. terminalis might be useful for inclusion in cosmetic products as an aging-enzyme antagonist.

Aldo Keto Reductases AKR1B1 and AKR1B10 in Cancer: Molecular Mechanisms and Signaling Networks

Deregulation of metabolic pathways has increasingly been appreciated as a major driver of cancer in recent years. The principal cancer-associated alterations in metabolism include abnormal uptake of glucose and amino acids and the preferential use of metabolic pathways for the production of biomass and nicotinamide adenine dinucleotide phosphate (NADPH). Aldo-keto reductases (AKRs) are NADPH dependent cytosolic enzymes that can catalyze the reduction of carbonyl groups to primary and secondary alcohols using electrons from NADPH. Aldose reductase, also known as AKR1B1, catalyzes the conversion of excess glucose to sorbitol and has been studied extensively for its role in a number of diabetic pathologies. In recent years, however, high expression of the AKR1B and AKR1C family of enzymes has been strongly associated with worse outcomes in different cancer types. This review provides an overview of the catalysis-dependent and independent data emerging on the molecular mechanisms of the functions of AKRBs in different tumor models with an emphasis of the role of these enzymes in chemoresistance, inflammation, oxidative stress and epithelial-to-mesenchymal transition.