Ginger compound [6]-shogaol and its cysteine-conjugated metabolite (M2) activate Nrf2 in colon epithelial cells in vitro and in vivo

Natural products as non-covalent and covalent modulators of the KEAP1/NRF2 pathway exerting antioxidant effects

By controlling several antioxidant and detoxifying genes at the transcriptional level, including NAD(P)H quinone oxidoreductase 1 (NQO1), multidrug resistance-associated proteins (MRPs), UDP-glucuronosyltransferase (UGT), glutamate-cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits, glutathione S-transferase (GST), sulfiredoxin1 (SRXN1), and heme-oxygenase-1 (HMOX1), the KEAP1/NRF2 pathway plays a crucial role in the oxidative stress response. Accordingly, the discovery of modulators of this pathway, activating cellular signaling through NRF2, and targeting the antioxidant response element (ARE) genes is pivotal for the development of effective antioxidant agents. In this context, natural products could represent promising drug candidates for supplementation to provide antioxidant capacity to human cells. In recent decades, by coupling in silico and experimental methods, several natural products have been characterized to exert antioxidant effects by targeting the KEAP1/NRF2 pathway. In this review article, we analyze several natural products that were investigated experimentally and in silico for their ability to modulate KEAP1/NRF2 by non-covalent and covalent mechanisms. These latter represent the two main sections of this article. For each class of inhibitors, we reviewed their antioxidant effects and potential therapeutic applications, and where possible, we analyzed the structure-activity relationship (SAR). Moreover, the main computational techniques used for the most promising identified compounds are detailed in this survey, providing an updated view on the development of natural products as antioxidant agents.

Influence of Diet on the Bioavailability of Active Components from Zingiber officinale Using an In Vitro Digestion Model

Ginger (Zingiber officinale Rosc.) is a plant known all over the world that is used as a spice and as an ingredient in drinks, dietary supplements, and cosmetics. The growing availability of its fresh rhizomes makes it even more likely to be used in the diet, mainly due to its beneficial health properties and high content of polyphenols (gingerols and shogaols). The main goal and motivation of the authors was to assess the bioavailability of active substances contained in the extract from ginger rhizomes in the presence of various types of diets using the in vitro digestion method, enabling simulation of the processes occurring during the digestion and absorption of metabolites in the small intestine. For the qualitative and quantitative analyses, the HPLC-MS (High Performance Liquid Chromatography-Mass Spectrometry) and HPLC (High Performance Liquid Chromatography) techniques were used, respectively. Based on the obtained results, it was found that the best bioavailability of the selected ginger polyphenols (6-gingerol, 8-gingerdione, 8-shogaol, and 10-gingerdione) was estimated for a high-fiber diet, while the weakest results were obtained for standard and basic diets. In the case of the high-fiber diet, the bioavailability of the mentioned compounds was estimated as 33.3, 21.4, 6.73, and 21.0%, while for the basic diet, it was only 21.3, 5.3, 2.0, and 1.0%, respectively.

Absorption and Metabolism of Ginger Compounds in Broiler Chicks

Bioavailability is critical in ensuring bioefficacy of ginger compounds, which have not been studied in chicks. In this study, day-old chicks were treated with ginger root extract at 0.0, 0.4, 0.8, 1.5, and 3.0% for 42 days. The gingerols and shogaols in chick samples were analyzed by liquid chromatography-mass spectrometry. The primary phase-I metabolic pathway for gingerols and shogaols was the reduction of ketone groups into hydroxyl groups. Shogaols were also metabolized through thiol conjugation and hydrogenation of double-bond pathways. Within the bloodstream, gingerols and their metabolites predominantly existed as glucuronidate or sulfate conjugates. However, the levels of the free form and conjugates were comparable for shogaols. In breast meat, the quantities of both the free form and conjugates for all compounds were similar. In plasma, more than 50% of absorbed 6-gingerol (6G) and 90% of absorbed 6-shogaol underwent reduction to their respective metabolites. However, in breast meat, the percentage of reduction for absorbed 6G was less than 50%, and for absorbed 6-shogaol, it was less than 60%. Ginger compounds were absorbed into chick plasma ranging from 1.4 to 8.5 μg/mL and breast meat ranging from 7.1 to 114.6 μg/100 g across the 0.4-3.0% dose range in a dose-dependent manner.

Two new diterpenoids from the rhizomes of Zingiber officinale

Two undescribed labdane diterpenoids (5S,8S,9R,10S,11E)-8,17-epoxy-13,14-dinorlabd-11-en-13-one (1) and (5S,9R,10S,12E)-17-hydroxy-labd-7,12-dien-15(16)-olide (2), together with seven known sesquiterpenoids (3-9) and two known monoterpenoids (10-11) were isolated from the dried rhizome of Zingiber officinale. Their structures were elucidated by detailed spectroscopic data (IR, UV, HR-ESI-MS, 1D and 2D NMR), X-ray crystallographic and ECD analysis. Moreover, all the 11 compounds were tested for α-glucosidase inhibitory effects and 9 was found to exhibit stronger inhibitory effects at IC50 = 4.8 μM against a positive control acarbose with IC50 = 414.6 μM.

A comprehensive review on soft rot disease management in ginger (Zingiber officinale) for enhancing its pharmaceutical and industrial values

Zingiber officinale L. Roscoe is a significant herb that possesses many medicinal and ethnomedicinal properties. Due to the presence of various bioactive compounds, it has immense healing capacity. However, ginger as a crop is susceptible to several fungal pathogens. Among all the fungal pathogens, Pythium and Fusarium spp. are of most concern, causing soft rot (rhizome rot) disease, majorly responsible for the downfall in its production by 50-90%. Pesticides and fungicides spray is generally recommended for the control of soft rot. Ample use of chemicals not only affects the quality of the crop but also disturbs ecological integrity. Therefore, biological methods of disease management involving suitable microbial agents such as Trichoderma harzianum, Pseudomonas spp., Bacillus subtilis, Streptomyces spp. and plant extracts are attracting and gaining importance as a part of integrated approaches (IPM) to manage the soft rot and sustainably enhance the production and improve the medicinal and pharmaceutical values of ginger. The present review is aimed to discuss various means of controlling soft rot disease by physical, chemical, biological, and nanotechnology-based methods. Moreover, various bioactive constituents of ginger and their pharmaceutical importance have been also discussed.

Synthesis of New Shogaol Analogues as NRF2 Activators and Evaluation of Their Anti-Inflammatory Activity, Modes of Action and Metabolic Stability

6-shogaol is a natural and the most potent bioactive vanilloid in dried Zingiber officinale rhizomes. Many scientific studies have reported the diverse biological activities of 6-shogaol. However, the major drawback of 6-shogaol is its instability at room temperature. We synthesised new shogaol thiophene compounds (STCs) by replacing the pentyl group in the sidechain with thiophene derivatives. The STCs were tested for their nuclear factor erythroid 2-related factor 2 (NRF2) activation ability in murine hepatoma cells (Hepa1c1c-7) by determining their NAD(P)H quinone oxidoreductase 1 (NQO1) inducing ability and expression of NRF2-associated antioxidant genes. The anti-inflammatory activity of STCs was determined in Escherichia coli lipopolysaccharide (LPS_Ec)-stimulated NR2-proficient and -silenced mouse microglial cells (BV-2) by measuring the inflammatory markers, cytokines, and mediators. The modes of action (interacting with the Kelch domain of KEAP1, covalent bonding with cysteines of KEAP1, and inhibition of GSK-3β enzyme activity) of NRF2 activation by STCs were determined using commercially available kits. The in vitro metabolic stability of the STCs in liver microsomes (humans, rats, and mice) was also investigated. The molecular docking and molecular dynamics studies were conducted to identify the binding poses, stability, and molecular interactions of the STCs in the binding pockets of Kelch and BTB domains of KEAP1 and GSK-3β enzyme. The new STCs were synthesised in good yields of > 85%, with a purity of about 95%, using a novel synthesis method by employing a reusable proline-proline dipeptide catalyst. The STCs are more potent than 6-shogaol in activating NRF2 and reducing inflammation. The nature of substituents on thiophene has a profound influence on the bioactivity of the STCs. Phenylthiophene STC (STC5) is the most potent, while thiophenes containing electron-withdrawing groups showed weaker bioactivity. The bioactivity of 6-shogaol is in the micromolar range, whereas STC5 showed bioactivity in the sub micromolar range. The STCs showed anti-inflammatory effects via NRF2-dependent and NRF2-independent mechanisms. The STCs improved NRF2 activity through multiple (KEAP1-independent and -dependent) mechanisms. The STCs showed decreased reactivity with thiols than 6-shogaol and thus may possess fewer side-effects than 6-shogaol. The STCs were more metabolically stable than 6-shogaol.

Engineering piperlongumine-inspired analogs as Nrf2-dependent neuroprotectors against oxidative damage by an electrophilicity-based strategy

Oxidative stress contributes significantly to the development of neurodegenerative diseases, thus developing nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent neuroprotectors is highly required for either prevention or treatment of these diseases. This work highlights an electrophilicity-based strategy that allows finding more active Nrf2-dependent neuroprotectors than natural piperlongumine (PL). Electrophilic modification was applied on both the exocylic and endocyclic Michael acceptors of PL, which includes placement of an electron-withdrawing trifluoromethyl group on its aromatic ring in the ortho, meta, or para position to the exocyclic olefin, and further introduction of an electron-withdrawing α-chlorine on its lactam ring. From a panel of PL analogs, we identified PLCl-4CF₃, characterized by the presence of p-trifluoromethyl group and α-chlorine, to be significantly superior to the parent PL in protecting PC12 cells from oxidative damage induced by 6-hydroxydopamine hydrochloride. Mechanistic studies reveal that the increased electrophilicity of PLCl-4CF₃ in its two Michael acceptors allows its ability to covalently modify Cys-151 at Keap1, facilitating inhibition against Nrf2 ubiquitination, translocation of Nrf2 into the nucleus, induction of phase 2 enzymes and final protection of PC12 cells from oxidative damage.

Transcriptome and proteomics conjoint analysis reveal metastasis inhibitory effect of 6-shogaol as ferroptosis activator through the PI3K/AKT pathway in human endometrial carcinoma in vitro and in vivo

Endometrial cancer remains as one of the widespread female malignancies despite the existing treatment measures mainly surgery, radiotherapy, and chemotherapy. In recent times, studies have focused on medicinal plants such as ginger due to its multifaceted characteristics compared to conventional medicine. 6-Shogaol is regarded as the main active compound of ginger participating in pharmacological activities and combating various health disorders, especially cancer. In our study, we compared the effects of 6-gingerol, 6-paradol, and 6-shogaol on Ishikawa cells, and found 6-shogaol as a more effective ingredient against Ishikawa cell proliferation. Moreover, its promoted ferroptosis, as a result, triggered mitochondrial morphologic alternation, as well as changed iron concentration, GSH and MDA levels. Furthermore, 6-Shogaol inhibited cell metastasis by influencing cell invasion and migration. Finally, 6-shogaol could trigger PI3K/AKT signaling pathways in vitro and in vivo confirmed by western blotting assay and immunohistochemical evaluation. These findings suggest that 6-shogaol can be used as promising functional food component in health diet and in drug target methods for endometrial cancer therapy.

Impact of Sulfur Fumigation on Ginger: Chemical and Biological Evidence

We previously found that sulfur fumigation, a commonly used controversial method for the post-harvest handling of ginger, induces the generation of a compound in ginger, which was speculated to be a sulfur-containing derivative of 6-shogaol based on its mass data. However, the chemical and biological properties of the compound remain unknown. As a follow-up study, here we report the chemical structure, systemic exposure, and anticancer activity of the compound. Chromatographic separation, nuclear magnetic resonance analysis, and chemical synthesis structurally elucidated the compound as 6-gingesulfonic acid. Pharmacokinetics in rats found that 6-gingesulfonic acid was more slowly absorbed and eliminated, with more prototypes existing in the blood than 6-shogaol. Metabolism profiling indicated that the two compounds produced qualitatively and quantitatively different metabolites. It was further found that 6-gingesulfonic acid exerted significantly weaker antiproliferative activity on tumor cells than 6-shogaol. The data provide chemical and biological evidence that sulfur fumigation may impair the healthcare functions of ginger.

Polyphenol-Rich Ginger (Zingiber officinale) for Iron Deficiency Anaemia and Other Clinical Entities Associated with Altered Iron Metabolism

Ginger (Zingiber officinale) is rich in natural polyphenols and may potentially complement oral iron therapy in treating and preventing iron deficiency anaemia (IDA). This narrative review explores the benefits of ginger for IDA and other clinical entities associated with altered iron metabolism. Through in vivo, in vitro, and limited human studies, ginger supplementation was shown to enhance iron absorption and thus increase oral iron therapy's efficacy. It also reduces oxidative stress and inflammation and thus protects against excess free iron. Ginger's bioactive polyphenols are prebiotics to the gut microbiota, promoting gut health and reducing the unwanted side effects of iron tablets. Moreover, ginger polyphenols can enhance the effectiveness of erythropoiesis. In the case of iron overload due to comorbidities from chronic inflammatory disorders, ginger can potentially reverse the adverse impacts and restore iron balance. Ginger can also be used to synthesise nanoparticles sustainably to develop newer and more effective oral iron products and functional ingredients for IDA treatment and prevention. Further research is still needed to explore the applications of ginger polyphenols in iron balance and anaemic conditions. Specifically, long-term, well-designed, controlled trials are required to validate the effectiveness of ginger as an adjuvant treatment for IDA.

Pharmacokinetics of Gingerols, Shogaols, and Their Metabolites in Asthma Patients

6-Gingerol and 6-shogaol are the most abundant gingerols and shogaols in ginger root and have been shown to reduce the asthmatic phenotype in murine models of asthma. Several studies have described the pharmacokinetics of gingerols and shogaols in humans following the oral ingestion of ginger, while little was known about the metabolism of these components in humans, particularly in patients with asthma. In this study, a dietary supplement of 1.0 g of ginger root extract was administered to asthma patients twice daily for 56 days and serum samples were drawn at 0.5-8 h on days 0, 28, and 56. The metabolic profiles of gingerols and shogaols in human plasma and the kinetic changes of gingerols, shogaols, and their metabolites in asthma patients collected on the three different visits were analyzed using liquid chromatography-mass spectrometry (LC-MS). Ketone reduction was the major metabolic pathway of both gingerols and shogaols. Gingerdiols were identified as the major metabolites of 6-, 8-, and 10-gingerols. M11 and M9 were identified as the double-bond reduction and both the double-bond and ketone reduction metabolites of 6-shogaol, respectively. Cysteine conjugation was another major metabolic pathway of 6-shogaol in asthma patients, and two cysteine-conjugated 6-shogaol, M1 and M2, were identified as the major metabolites of 6-shogaol. Furthermore, gingerols, shogaols, and their metabolites were quantitated in the human serum collected at different time points during each of the three visits using a very sensitive high-resolution LC-MS method. The results showed that one-third of 6-gingerol was metabolized to produce its reduction metabolites, 6-gingerdiols, and more than 90% of 6-shogaol was metabolized to its phase I and cysteine-conjugated metabolites, suggesting the importance of considering the contribution of these metabolites to the bioavailability and health beneficial effects of gingerols and shogaols. All gingerols, shogaols, and their metabolites reached their peak concentrations in less than 2 h, and their half-lives (t1/2) were from 0.6 to 2.4 h. Furthermore, long-term treatment of ginger supplements, especially after 56 days of treatment, increases the absorption of ginger compounds and their metabolites in asthma patients.

Potential Role of Ginger (Zingiber officinale Roscoe) in the Prevention of Neurodegenerative Diseases

Ginger is composed of multiple bioactive compounds, including 6-gingerol, 6-shogaol, 10-gingerol, gingerdiones, gingerdiols, paradols, 6-dehydrogingerols, 5-acetoxy-6-gingerol, 3,5-diacetoxy-6-gingerdiol, and 12-gingerol, that contribute to its recognized biological activities. Among them, the major active compounds are 6-shogaol and 6-gingerol. Scientific evidence supports the beneficial properties of ginger, including antioxidant and anti-inflammatory capacities and in contrast, a specific and less studied bioactivity is the possible neuroprotective effect. The increase in life expectancy has raised the incidence of neurodegenerative diseases (NDs), which present common neuropathological features as increased oxidative stress, neuroinflammation and protein misfolding. The structure-activity relationships of ginger phytochemicals show that ginger can be a candidate to treat NDs by targeting different ligand sites. Its bioactive compounds may improve neurological symptoms and pathological conditions by modulating cell death or cell survival signaling molecules. The cognitive enhancing effects of ginger might be partly explained via alteration of both the monoamine and the cholinergic systems in various brain areas. Moreover, ginger decreases the production of inflammatory related factors. The aim of the present review is to summarize the effects of ginger in the prevention of major neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and multiple sclerosis.

Effects of the Phytochemical Combination PB123 on Nrf2 Activation, Gene Expression, and the Cholesterol Pathway in HepG2 Cells

There has been a long history of human usage of the biologically-active phytochemicals in Salvia rosmarinus, Zingiber officinale, and Sophora japonica for health purposes, and we recently reported on a combination of those plant materials as the PB123 dietary supplement. In the present work we extended those studies to evaluate activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor and differential gene expression in cultured HepG2 (hepatocellular carcinoma) cells treated with PB123. We determined transcriptome changes using mRNA-seq methods, and analyzed the affected pathways using Ingenuity Pathway Analysis and BioJupies, indicating that primary effects included increasing the Nrf2 pathway and decreasing the cholesterol biosynthesis pathway. Pretreatment of cultured HepG2 cells with PB123 upregulated Nrf2-dependent cytoprotective genes and increased cellular defenses against cumene hydroperoxide-induced oxidative stress. In contrast, pretreatment of cultured HepG2 cells with PB123 downregulated cholesterol biosynthesis genes and decreased cellular cholesterol levels. These findings support the possible beneficial effects of PB123 as a healthspan-promoting dietary supplement.

6-Shogaol attenuated ethylene glycol and aluminium chloride induced urolithiasis and renal injuries in rodents

The 6-shogaol, is a flavanone type flavonoid that is abundant in citrus fruit and has a wide range of pharmacological effects. The present study attempted to evaluate the antiurolithic effect of 6-shogaol on ethylene glycol (EG) and ammonium chloride (AC)-induced experimental urolithiasis in rats. The efficacy of 6-shogaol 50 mg/kg and 100 mg/kg was studied in EG 0.75% (V/V) and AC 1% (W/V) experimentally induced urolithiasis in rats for 21 days. The weight difference, urine volume, the levels of calcium, phosphate, magnesium, oxalate and uric acid in urine was observed. The blood urea nitrogen, creatinine, uric acid in serum and levels of malondialdehyde (MDA) and glutathione (GSH) were also measured. Histopathological analyses in kidneys were also performed. The rats weights were higher in the 6-shogaol groups than the urolithiasis group. EG caused a significant increase in serum creatinine (p < 0.05), BUN (P < 0.001), and uric acid (p < 0.01) while treatment with Cystone (750 mg/kg), and 6-shogaol (50 and 100 mg/kg) showed the significant reduction in increased serum levels of creatinine (p < 0.001), uric acid (p < 0.01) and BUN (p < 0.001). Administration of EG and AC showed statistically significant (p < 0.001) elevated levels of MDA and reduction in GSH levels. Treatment of Cystone (750 mg/kg), and 6-shogaol (50 and 100 mg/kg) significantly (p < 0.001) reduced MDA levels and an increase GSH levels as compared to EG and AC-treated group. The histological findings further attested antiurolithiatic properties of 6-shogaol. The present study attributed clinical shreds of evidence first time that claiming the significant antiurolithic effect of 6-shogaol and could be a cost-effective candidate for the prevention and treatment of urolithiasis.

Covalent Modification of Proteins by Plant-Derived Natural Products: Proteomic Approaches and Biological Impacts

Plant-derived natural products (NPs) with electrophilic functional groups engage various subsets of the proteome via covalent modification of nucleophilic cysteine residues. This electrophile-nucleophile interaction can change protein conformation, alter protein function, and modulate their biological action. The biological significance of these covalent protein modifications in health and disease is increasingly recognized. One way to understand covalent NP-protein interactions is to utilize traditional proteomics and modern mass spectrometry (MS)-based proteomic strategies. These strategies have proven effective in uncovering specific NP protein targets and are critical first steps that allow for a much deeper understanding of the ability of NPs to modulate cellular processes. Here, plant-derived NPs that covalently modify proteins are reviewed, the biological significance of these covalent modifications, and the different proteomic strategies that have been employed to study these NP-protein interactions.

A recent update on the multifaceted health benefits associated with ginger and its bioactive components

Due to recent lifestyle shifts and health discernments among consumers, synthetic drugs are facing the challenge of controlling disease development and progression. Various medicinal plants and their constituents are recognized for their imminent role in disease management via modulation of biological activities. At present, research scholars have diverted their attention on natural bioactive entities with health-boosting perception to combat the lifestyle-related disarrays. In particular, Zingiber officinale is a medicinal herb that has been commonly used in food and pharmaceutical products. Its detailed chemical composition and high value-added active components have been extensively studied. In this review, we have summarized the pharmacological potential of this well-endowed chemo preventive agent. It was revealed that its functionalities are attributed to several inherent chemical constituents, including 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 6-hydroshogaol, and oleoresin, which were established through many studies (in vitro, in vivo, and cell lines). In this review, we also focused on the therapeutic effects of ginger and its constituents for their effective antioxidant properties. Their consumption may reduce or delay the progression of related diseases, such as cancer, diabetes, and obesity, via modulation of genetic and metabolic activities. The updated data could elucidate the relationship of the extraction processes with the constituents and biological manifestations. We have collated the current knowledge (including the latest clinical data) about the bioactive compounds and bioactivities of ginger. Their detailed mechanisms, which can lay foundation for their food and medical applications are also discussed.

Precision Research on Ginger: The Type of Ginger Matters

Ginger is a widely consumed spice and possesses numerous pharmacological properties. However, studies addressing the efficacy of ginger in humans have been inconsistent. Many confounding factors need to be considered when evaluating the health effects from ginger against chronic diseases, especially the levels of bioactive components in the ginger formulations used in human trials. Gingerols, the major compounds in fresh ginger, are liable to dehydrate and convert to shogaols, the major compounds in dried ginger, as a result of the instability of β-hydroxyl ketone when exposed to heat and/or acidic conditions. As a result of various heating and processing methods, the concentrations of gingerols and shogaols in ginger products vary significantly. Increasing evidence has shown that gingerols and shogaols have different bioactivities, molecular targets, and metabolic pathways, suggesting the importance of identifying the optimal oral ginger composition for a specific disease. In this perspective, we highlighted differences in the composition between fresh ginger and dry ginger, bioactivities, molecular targets, and metabolic pathways of gingerols and shogaols as well as future perspectives regarding precision research on ginger.

Potential of phytochemicals as immune-regulatory compounds in atopic diseases: A review

Atopic diseases (atopic dermatitis, asthma and allergic rhinitis) affects a huge number of people around the world and their incidence rate is on rise. Atopic dermatitis (AD) is more prevalent in paediatric population which sensitizes an individual to develop allergic rhinitis and asthma later in life. The complex pathogenesis of these allergic diseases though involves numerous cellular signalling pathways but redox imbalance has been reported to be critical for induction/perpetuation of inflammatory process under such conditions. The realm of complementary and alternative medicine has gained greater attention because of the reported anti-oxidant/anti-inflammatory properties. Several case studies of treating atopic diseases with homeopathic remedies have provided positive results. Likewise, pre-clinical studies suggest that various natural compounds suppress allergic response via exhibiting their anti-oxidant potential. Despite the reported beneficial effects of phytochemicals in experimental model system, the clinical success has not been documented so far. It appears that poor absorption and bioavailability of natural compounds may be one of the reasons for realizing their full potential. The current paper throws light on impact of phytochemicals in the redox linked cellular and signalling pathways that may be critical in manifestation of atopic diseases. Further, an effort has been made to identify the gaps in the area so that future strategies could be evolved to exploit the medicinal value of various phytochemicals for an improved efficiency.

Seaweed natural products modify the host inflammatory response via Nrf2 signaling and alter colon microbiota composition and gene expression

Seaweeds are an important component of human diets, especially in Asia and the Pacific islands, and have shown chemopreventive as well as anti-inflammatory properties. However, structural characterization and mechanistic insight of seaweed components responsible for their biological activities are lacking. We isolated cymopol and related natural products from the marine green alga Cymopolia barbata and demonstrated their function as activators of transcription factor Nrf2-mediated antioxidant response to increase the cellular antioxidant status. We probed the reactivity of the bioactivation product of cymopol, cymopol quinone, which was able to modify various cysteine residues of Nrf2's cytoplasmic repressor protein Keap1. The observed adducts are reflective of the polypharmacology at the level of natural product, due to multiple electrophilic centers, and at the amino acid level of the cysteine-rich target protein Keap1. The non-polar C. barbata extract and its major active component cymopol, reduced inflammatory gene transcription in vitro in macrophages and mouse embryonic fibroblasts in an Nrf2-dependent manner. Cymopol-containing extracts attenuated neutrophil migration in a zebrafish tail wound model. RNA-seq analysis of colonic tissues of mice exposed to non-polar extract or cymopol showed an antioxidant and anti-inflammatory response, with more pronounced effects exhibited by the extract. Cymopolia extract reduced DSS-induced colitis as measured by fecal lipocalin concentration. RNA-seq showed that mucosal-associated bacterial composition and transcriptional profile in large intestines were beneficially altered to varying degrees in mice treated with either the extract or cymopol. We conclude that seaweed-derived compounds, especially cymopol, alter Nrf2-mediated host and microbial gene expression, thereby providing polypharmacological effects.

6-Shogaol Inhibits Advanced Glycation End-Products-Induced IL-6 and ICAM-1 Expression by Regulating Oxidative Responses in Human Gingival Fibroblasts

Advanced glycation end-products (AGEs) cause diabetes mellitus (DM) complications and accumulate more highly in periodontal tissues of patients with periodontitis and DM. AGEs aggravate periodontitis with DM by increasing the expression of inflammation-related factors in periodontal tissues. 6-Shogaol, a major compound in ginger, has anti-inflammatory and anti-oxidative activities. However, the influence of shogaol on DM-associated periodontitis is not well known. In this study, the effects of 6-shogaol on AGEs-induced oxidative and anti-oxidative responses, and IL-6 and ICAM-1 expression in human gingival fibroblasts (HGFs) were investigated. When HGFs were cultured with 6-shogaol and AGEs, the activities of reactive oxygen species (ROS) and antioxidant enzymes (heme oxygenase-1 [HO-1] and NAD(P)H quinone dehydrogenase 1 [NQO1]), and IL-6 and ICAM-1 expressions were investigated. RAGE expression and phosphorylation of MAPKs and NF-κB were examined by western blotting. 6-Shogaol significantly inhibited AGEs-induced ROS activity, and increased HO-1 and NQO1 levels compared with the AGEs-treated cells. The AGEs-stimulated expression levels of receptor of AGE (RAGE), IL-6 and ICAM-1 and the phosphorylation of p38, ERK and p65 were attenuated by 6-shogaol. These results suggested that 6-shogaol inhibits AGEs-induced inflammatory responses by regulating oxidative and anti-oxidative activities and may have protective effects on periodontitis with DM.

Gingers and Their Purified Components as Cancer Chemopreventative Agents

Chemoprevention by ingested substituents is the process through which nutraceuticals and/or their bioactive components antagonize carcinogenesis. Carcinogenesis is the course of action whereby a normal cell is transformed into a neoplastic cell. This latter action involves several steps, starting with initiation and followed by promotion and progression. Driving these stages is continued oxidative stress and inflammation, which in turn, causes a myriad of aberrant gene expressions and mutations within the transforming cell population and abnormal gene expressions by the cells within the surrounding lesion. Chemoprevention of cancer with bioreactive foods or their extracted/purified components occurs primarily via normalizing these inappropriate gene activities. Various foods/agents have been shown to affect different gene expressions. In this review, we discuss how the chemoprevention activities of gingers antagonize cancer development.

6-Shogaol protects against ischemic acute kidney injury by modulating NF-κB and heme oxygenase-1 pathways

Acute kidney injury (AKI) due to renal ischemia-reperfusion (I/R) is a major clinical problem without effective therapy. Ginger is one of the most widely consumed spices in the world, and 6-shogaol, a major ginger metabolite, has anti-inflammatory effects in neuronal and epithelial cells. Here, we demonstrate our novel findings that 6-shogaol treatment protected against renal I/R injury with decreased plasma creatinine, blood urea nitrogen, and kidney neutrophil gelatinase-associated lipocalin mRNA synthesis compared with vehicle-treated mice subjected to renal I/R. Additionally, 6-shogaol treatment reduced kidney inflammation (decreased proinflammatory cytokine and chemokine synthesis as well as neutrophil infiltration) and apoptosis (decreased TUNEL-positive renal tubular cells) compared with vehicle-treated mice subjected to renal I/R. In cultured human and mouse kidney proximal tubule cells, 6-shogaol significantly attenuated TNF-α-induced inflammatory cytokine and chemokine mRNA synthesis. Mechanistically, 6-shogaol significantly attenuated TNF-α-induced NF-κB activation in human renal proximal tubule cells by reducing IKKαβ/IκBα phosphorylation. Furthermore, 6-shogaol induced a cytoprotective chaperone heme oxygenase (HO)-1 via p38 MAPK activation in vitro and in vivo. Consistent with these findings, pretreatment with the HO-1 inhibitor zinc protoporphyrin IX completely prevented 6-shogaol-mediated protection against ischemic AKI in mice. Taken together, our study showed that 6-shogaol protects against ischemic AKI by attenuating NF-κB activation and inducing HO-1 expression. 6-Shogaol may provide a potential therapy for ischemic AKI during the perioperative period.

Bioactive Compounds and Bioactivities of Ginger (Zingiber officinale Roscoe)

Ginger (Zingiber officinale Roscoe) is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. The health benefits of ginger are mainly attributed to its phenolic compounds, such as gingerols and shogaols. Accumulated investigations have demonstrated that ginger possesses multiple biological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, neuroprotective, cardiovascular protective, respiratory protective, antiobesity, antidiabetic, antinausea, and antiemetic activities. In this review, we summarize current knowledge about the bioactive compounds and bioactivities of ginger, and the mechanisms of action are also discussed. We hope that this updated review paper will attract more attention to ginger and its further applications, including its potential to be developed into functional foods or nutraceuticals for the prevention and management of chronic diseases.

The Role of Natural Products in Targeting Cardiovascular Diseases via Nrf2 Pathway: Novel Molecular Mechanisms and Therapeutic Approaches

Cardiovascular diseases (CVDs) are closely linked to cellular oxidative stress and inflammation. This may be resulted from the imbalance generation of reactive oxygen species and its role in promoting inflammation, thereby contributing to endothelial dysfunction and cardiovascular complications. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that plays a significant role in regulating expression of antioxidant and cytoprotective enzymes in response to oxidative stress. Natural products have emerged as a potential source of bioactive compounds which have shown to protect against atherogenesis development by activating Nrf2 signaling. This review aims to provide a comprehensive summary of the published data on the function, regulation and activation of Nrf2 as well as the molecular mechanisms of natural products in regulating Nrf2 signaling. The beneficial effects of using natural bioactive compounds as a promising therapeutic approach for the prevention and treatment of CVDs are reviewed.

Potential of AKR1B10 as a Biomarker and Therapeutic Target in Type 2 Leprosy Reaction

The AKR1B10 (aldo-keto reductase family 1 member B10) gene has important functions in carcinogen-induced neoplasia. AKR1B10 is also expressed in type 2 reaction leprosy patients (R2). We measured the expression of AKR1B10 in the skin lesions of patients with leprosy by immunohistochemistry from biopsies that encompassed the spectrum of types of leprosy, based on the Ridley and Jopling classification [10 samples each of tuberculoid (TT), borderline tuberculoid (BT), mid-borderline (BB), and borderline lepromatous (BL) lesions; four samples of lepromatous lesions (LL)], reactional leprosy [14 samples of type 1 Reaction (R1) and 10 samples of type 2 Reaction (R2)], and biopsies from 9 healthy control (HC) subjects. In addition, 46 lepromatous lesions (BL and LL), 45 lepromatous lesions in regression, and 115 R2 lesions were included. Eight of 10 R2 samples (80%), 3 of 46 active BL and LL samples (6%), 23 of 45 BL and LL samples in regression (51%), and 107 of 115 R2 samples (93%) were positive for AKR1B10, differing significantly between all groups (p < 0.05). AKR1B10 expression was highest in the cytoplasm of macrophages. Thus, AKR1B10 is overexpressed on the lepromatous side (BL and LL) in samples that are in regression, especially type 2 reaction-associated lesions, rendering it a potential marker of type 2 reactional episodes of leprosy and a target of drugs against reactional episodes.

Applying an Electrophilicity-Based Strategy to Develop a Novel Nrf2 Activator Inspired from Dietary [6]-Shogaol

Activation of nuclear factor erythroid-2-related factor 2 (Nrf2) is a crucial cellular defense mechanisms against oxidative stress and also an effective means to decrease the risk of oxidative stress-related diseases including cancer. Thus, identifying novel Nrf2 activators is highly anticipated. Inspired from [6]-shogaol (6S), an active component of ginger, herein we developed a novel potent Nrf2 activator, (1E,4E)-1-(4-hydroxy-3-methoxyphenyl)-7-methylocta-1,4,6-trien-3-one (SA) by an electrophilicity-based strategy. Compared with the parent 6S, SA bearing a short but entirely conjugated unsaturated ketone chain manifested the improved electrophilicity and cytoprotection (cell viability for the 10 μM 6S- and SA-treated group being 48.9 ± 5.3% and 76.1 ± 3.2%, respectively) against tert-butylhydroperoxide ( t-BHP)-induced cell death (cell viability for the t-BHP-stimulated group being 42.4 ± 0.4%) of HepG2. Mechanistic study uncovers that SA works as a potent Nrf2 activator by inducing Keap1 modification, inhibiting Nrf2 ubiquitylation and phosphorylating ERK in a Michael acceptor-dependent fashion. Taking 6S as an example, this works illustrates the feasibility and importance of applying an electrophilicity-based strategy to develop Nrf2 activators with dietary molecules as an inspiration due to their low toxicity and extraordinarily diverse chemical scaffolds.

Occurrence, biological activity and metabolism of 6-shogaol

As one of the main bioactive compounds of dried ginger, 6-shogaol has been widely used to alleviate many ailments. It is also a major pungent flavor component, and its precursor prior to dehydration is 6-gingerol, which is reported to be responsible for the pungent flavor and biological activity of fresh ginger. Structurally, gingerols including 6-gingerol have a β-hydroxyl ketone moiety and is liable to dehydrate to generate an α,β-unsaturated ketone under heat and/or acidic conditions. The conjugation of the α,β-unsaturated ketone skeleton in the chemical structure of 6-shogaol explicates its higher potency and efficacy than 6-gingerol in terms of antioxidant, anti-inflammatory, anticancer, antiemetic and other bioactivities. Research on the health benefits of 6-shogaol has been conducted and results have been reported recently; however, scientific data are scattered due to a lack of systematic collection. In addition, action mechanisms of the preventive and/or therapeutic actions of 6-shogaol remain obscurely non-collective. Herein, we review the preparations, biological activity and mechanisms, and metabolism of 6-shogaol as well as the properties of 6-shogaol metabolites.

Nrf2 at the heart of oxidative stress and cardiac protection

The NFE2L2 gene encodes the transcription factor Nrf2 best known for regulating the expression of antioxidant and detoxification genes. Gene knockout approaches have demonstrated its universal cytoprotective features. While Nrf2 has been the topic of intensive research in cancer biology since its discovery in 1994, understanding the role of Nrf2 in cardiovascular disease has just begun. The literature concerning Nrf2 in experimental models of atherosclerosis, ischemia, reperfusion, cardiac hypertrophy, heart failure, and diabetes supports its cardiac protective character. In addition to antioxidant and detoxification genes, Nrf2 has been found to regulate genes participating in cell signaling, transcription, anabolic metabolism, autophagy, cell proliferation, extracellular matrix remodeling, and organ development, suggesting that Nrf2 governs damage resistance as well as wound repair and tissue remodeling. A long list of small molecules, most derived from natural products, have been characterized as Nrf2 inducers. These compounds disrupt Keap1-mediated Nrf2 ubquitination, thereby prohibiting proteasomal degradation and allowing Nrf2 protein to accumulate and translocate to the nucleus, where Nrf2 interacts with sMaf to bind to ARE in the promoter of genes. Recently alternative mechanisms driving Nrf2 protein increase have been revealed, including removal of Keap1 by autophagy due to p62/SQSTM1 binding, inhibition of βTrCP or Synoviolin/Hrd1-mediated ubiquitination of Nrf2, and de novo Nrf2 protein translation. We review here a large volume of literature reporting historical and recent discoveries about the function and regulation of Nrf2 gene. Multiple lines of evidence presented here support the potential of dialing up the Nrf2 pathway for cardiac protection in the clinic.

Oral Delivery of Nanoparticles Loaded With Ginger Active Compound, 6-Shogaol, Attenuates Ulcerative Colitis and Promotes Wound Healing in a Murine Model of Ulcerative Colitis

BACKGROUND AND AIMS

Oral drug delivery is the most attractive pathway for ulcerative colitis [UC] therapy, since it has many advantages. However, this strategy has encountered many challenges, including the instability of drugs in the gastrointestinal tract [GT], low targeting of disease tissues, and severe adverse effects. Nanoparticles capable of colitis tissue-targeted delivery and site-specific drug release may offer a unique and therapeutically effective system that addresses these formidable challenges.

METHODS

We used a versatile single-step surface-functionalising technique to prepare PLGA/PLA-PEG-FA nanoparticles loaded with the ginger active compound, 6-shogaol [NPs-PEG-FA/6-shogaol]. The therapeutic efficacy of NPs-PEG-FA/6-shogaol was evaluated in the well-established mouse model of dextran sulphate sodium [DSS]-induced colitis.

RESULTS

NPs-PEG-FA exhibited very good biocompatibility both in vitro and in vivo. Subsequent cellular uptake experiments demonstrated that NPs-PEG-FA could undergo efficient receptor-mediated uptake by colon-26 cells and activated Raw 264.7 macrophage cells. In vivo, oral administration of NPs-PEG-FA/6-shogaol encapsulated in a hydrogel system [chitosan/alginate] significantly alleviated colitis symptoms and accelerated colitis wound repair in DSS-treated mice by regulating the expression levels of pro-inflammatory [TNF-α, IL-6, IL-1β, and iNOS] and anti-inflammatory [Nrf-2 and HO-1] factors.

CONCLUSIONS

Our study demonstrates a convenient, orally administered 6-shogaol drug delivery system that effectively targets colitis tissue, alleviates colitis symptoms, and accelerates colitis wound repair. This system may represent a promising therapeutic approach for treating inflammatory bowel disease [IBD].

Interindividual Variability in Metabolism of [6]-Shogaol by Gut Microbiota

[6]-Shogaol (6S), one of the major bioactive components in dry ginger, is attracting considerable attention because of its wide spectrum of biological activities, but its metabolic fate is still not fully understood. In the present study, the microbial metabolism of 6S was examined for the first time in in vitro batch fecal fermentation system and in mice. Two major microbial metabolites were detected and identified as 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M9) and 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11). Our results indicated that reductions of the double bond and the ketone group are the major metabolic pathways of 6S by the human gut microbiota. We also observed the interindividual variability in the metabolism of M11 to M9 by human gut microbiota. In addition, we demonstrated that the glucuronidated form of 6S and its metabolites could be rapidly deconjugated by human gut microbiota and in mice, which can be regarded as a reactive process taking place in the intestinal tract. To our knowledge, this is the first report involving the identification of the microbial metabolites of 6S in an in vitro fermentation system, and the first demonstration of the critical role of gut microbiota in producing the bioactive free form of 6S and its metabolites in the intestinal tract in mice.

Specific bioactive compounds in ginger and apple alleviate hyperglycemia in mice with high fat diet-induced obesity via Nrf2 mediated pathway

Prolonged hyperglycemia activates the formation of advanced glycation end-products (AGEs). Major dicarbonyl compounds such as methylglyoxal or glyoxal are found to be the main precursors of AGEs and N(ε)-(carboxymethyl)lysine (CML) found to be predominantly higher in the diabetic population. We hypothesized that phloretin from apple and [6]-gingerol from ginger inhibit formation of AGEs and suppress the receptor for advanced glycation end products (RAGE) via nuclear factor erythroid-2-related-factor-2 (Nrf2)-dependent pathway. Phloretin and [6]-gingerol were supplemented at two different doses to C57BL/6 mice on high fat diet or standard diet for a period of 17weeks. Phloretin or [6]-gingerol supplementation significantly reduced plasma glucose, alanine aminotransferase, aspartate aminotransferase, AGEs and insulin levels. Phloretin and [6]-gingerol also decreased the levels of AGEs and CML levels, via Nrf2 pathway, enhancing GSH/GSSG ratio, heme oxygenase-1 and glyoxalase 1 in liver tissue. These results suggest that phloretin and [6]-gingerol are potential dietary compounds that can alleviate diabetes-induced complications.

Protective effects of phenolics rich extract of ginger against Aflatoxin B1-induced oxidative stress and hepatotoxicity

Aflatoxin B1 (AFB1) is one of the predominant mycotoxin contaminant in food and feed, causing oxidative stress and hepatotoxicity. Ginger phenolics have been reported for its antioxidant potential and hepatoprotective activity. The present study investigated the protective effects of phenolics rich ginger extract (GE) against AFB1 induced oxidative stress and hepatotoxicity, in vitro and in vivo. The phenolic acid profiles of GE showed 6-gingerol and 6-shogaol as predominant components. Pretreatment of HepG2 cells with GE significantly inhibited the production of intracellular reactive oxygen species (ROS), DNA strand break, and cytotoxicity induced by AFB1. A comparable effect was observed in in vivo. Male Wistar rats were orally treated with GE (100 and 250mg/kg) daily, with the administration of AFB 1 (200μg/kg) every alternative day for 28days. Treatment with GE significantly reduced AFB1 induced toxicity on the serum markers of liver damage. In addition, GE also showed significant hepatoprotective effect by reducing the lipid peroxidation and by enhancing the antioxidant enzymes activities. These results combined with liver histopathological observations indicated that GE has potential protective effect against AFB1 induced hepatotoxicity. Additionally, administration of GE up-regulated Nrf2/HO-1 pathway, which further proved the efficiency of GE to inhibit AFB1 induced hepatotoxicity.

In vitro and in vivo inhibition of aldose reductase and advanced glycation end products by phloretin, epigallocatechin 3-gallate and [6]-gingerol

Hyperglycemic stress activates polyol pathway and aldose reductase (AR) key enzyme responsible for generating secondary complications during diabetes. In this study the therapeutic potential of phloretin, epigallocatechin 3-gallate (EGCG) and [6]-gingerol were evaluated for anti-glycating and AR inhibitory activity in vitro and in vivo systems. Human retinal pigment epithelial (HRPE) cells were induced with high glucose supplemented with the phloretin, EGCG and [6]-gingerol. Aldose reductase activity, total advanced glycation end products (AGEs) and enzyme inhibitor kinetics were assessed. Male C57BL/6J mice were randomly assigned to one of the different treatments (bioactive compounds at 2 concentrations each) with either a low fat diet or high fat diet (HFD). After sixteen weeks, AGE accumulation and AR activity was determined in heart, eyes and kidney. High glucose induced toxicity decreased cell viability compared to the untreated cells and AR activity increased to 2-5 folds from 24 to 96h. Pre-treatment of cells with phloretin, EGCG and [6]-gingerol improved cell viability and inhibited AR activity. The enzyme inhibition kinetics followed a non-competitive mode of inhibition for phloretin and EGCG whereas [6]-gingerol indicated uncompetitive type of inhibition against AR. Data from the animal studies showed high plasma glucose levels in HFD group over time, compared to the low fat diet. HFD group developed cataract and AR activity increased to 4 folds compared to the group with low fat diet. Administration of EGCG, phloretin and [6]-gingerol significantly reduced blood sugar levels, AGEs accumulation, and AR activity. These findings could provide a basis to consider using the selected dietary components alone or in combination with other therapeutic approaches to prevent diabetes-related complications in humans.

Synthesis, evaluation, and metabolism of novel [6]-shogaol derivatives as potent Nrf2 activators

Oxidative stress is a central component of many chronic diseases. The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 p45-related factor 2 (Nrf2) system is a major regulatory pathway of cytoprotective genes against oxidative and electrophilic stress. Activation of the Nrf2 pathway plays crucial roles in the chemopreventive effects of various inducers. In this study, we developed a novel class of potent Nrf2 activators derived from ginger compound, [6]-shogaol (6S), using the Tg[glutathione S-transferase pi 1 (gstp1):green fluorescent protein (GFP)] transgenic zebrafish model. Investigation of structure-activity relationships of 6S derivatives indicates that the combination of an α,β-unsaturated carbonyl entity and a catechol moiety in one compound enhances the Tg(gstp1:GFP) fluorescence signal in zebrafish embryos. Chemical reaction and in vivo metabolism studies of the four most potent 6S derivatives showed that both α,β-unsaturated carbonyl entity and catechol moiety act as major active groups for conjugation with the sulfhydryl groups of the cysteine residues. In addition, we further demonstrated that 6S derivatives increased the expression of Nrf2 downstream target, heme oxygenase-1, in both a dose- and time-dependent manner. These results suggest that α,β-unsaturated carbonyl entity and catechol moiety of 6S derivatives may react with the cysteine residues of Keap1, disrupting the Keap1-Nrf2 complex, thereby liberating and activating Nrf2. Our findings of natural product-derived Nrf2 activators lead to design options of potent Nrf2 activators for further optimization.

Toward an understanding of the role of a catechol moiety in cancer chemoprevention: The case of copper- and o-quinone-dependent Nrf2 activation by a catechol-type resveratrol analog

SCOPE

Catechol moieties are commonly present in dietary natural products that exert cancer chemopreventive activity. While the oxidative conversion of catechols into their corresponding o-quinones is generally considered to contribute to their cancer chemopreventive effects, the mechanism of the intracellular conversion has not been fully elucidated.

METHODS AND RESULTS

Among resveratrol and its hydroxylated analogs examined, only 3,4-dihydroxy-trans-stilbene exerted cytoprotective effects against t-butylhydroperoxide-induced death of HepG2 cells. This resveratrol analog activated the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway through stimulating phosphorylation of Akt and inducing keap1 modification, thereby resulting in its nuclear translocation and subsequent transcriptional induction of phase II detoxifying enzymes. Its cytoprotective effect through Nrf2 activation was largely abrogated by pretreatment of cells with DTT, a sulfhydryl-containing nucleophile, and neocuproine, a specific chelating agent for copper ions.

CONCLUSION

We identified 3,4-dihydroxy-trans-stilbene as a novel Nrf2 activator that is converted intracellularly into its corresponding o-quinone electrophile by copper ions. The copper-mediated oxidation was required for the Nrf2 activation, subsequent transcriptional induction of phase II detoxifying enzymes and ultimately for cytoprotection. The findings demonstrate a previously underrecognized role for intracellular copper ions in the cancer chemopreventive effects of catechol-containing dietary natural products.

Activation of Nrf2 target enzymes conferring protection against oxidative stress in PC12 cells by ginger principal constituent 6-shogaol

Natural compounds containing phenoxyl groups and/or Michael acceptor units appear to possess antioxidant and cytoprotective properties. The ginger principal constituent 6-shogaol (6-S) represents one of such compounds. In this study, we reported that 6-S efficiently scavenges various free radicals in vitro, and displays remarkable cytoprotection against oxidative stress-induced cell damage in the neuron-like rat pheochromocytoma cell line, PC12 cells. Pretreatment of PC12 cells with 6-S significantly upregulates a series of phase II antioxidant molecules, such as glutathione, heme oxygenase 1, NAD(P)H: quinone oxidoreductase 1, thioredoxin reductase 1, and thioredoxin 1. A mechanistic study revealed that 6-S enhanced the translocation of Nrf2 from the cytosol to the nucleus and knockdown of Nrf2 abolished such protection, indicating that this cytoprotection is mediated by the activation of the transcription factor Nrf2. Another ginger constituent 6-gingerol (6-G), having a similar structure of 6-S but lacking the alpha,beta-unsaturated ketone structure (Michael acceptor moiety), failed to shelter PC12 cells from oxidative stress. Our results demonstrate that 6-S is a novel small molecule activator of Nrf2 in PC12 cells, and suggest that 6-S might be a potential candidate for the prevention of oxidative stress-mediated neurodegenerative disorders.

Modulation of Metabolic Detoxification Pathways Using Foods and Food-Derived Components: A Scientific Review with Clinical Application

Research into human biotransformation and elimination systems continues to evolve. Various clinical and in vivo studies have been undertaken to evaluate the effects of foods and food-derived components on the activity of detoxification pathways, including phase I cytochrome P450 enzymes, phase II conjugation enzymes, Nrf2 signaling, and metallothionein. This review summarizes the research in this area to date, highlighting the potential for foods and nutrients to support and/or modulate detoxification functions. Clinical applications to alter detoxification pathway activity and improve patient outcomes are considered, drawing on the growing understanding of the relationship between detoxification functions and different disease states, genetic polymorphisms, and drug-nutrient interactions. Some caution is recommended, however, due to the limitations of current research as well as indications that many nutrients exert biphasic, dose-dependent effects and that genetic polymorphisms may alter outcomes. A whole-foods approach may, therefore, be prudent.