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

Ginger for treating nausea and vomiting: an overview of systematic reviews and meta-analyses

Ginger may be a potential remedy for nausea and vomiting. This review aimed to assess the reporting and methodological quality, and integrate the evidence in this field. A total of fifteen meta-analyses were analysed and met the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 guidelines, providing a relatively complete statement. However, methodological quality, assessed using the Assessment of Multiple Systematic Reviews-2 checklist, was deemed critically low to low. Our review's findings support ginger's effectiveness in managing chemotherapy-induced nausea and vomiting in cancer patients. It also reduces postoperative nausea and vomiting severity, decreasing the need for rescue antiemetics. Furthermore, ginger shows promise in alleviating pregnancy-related nausea and vomiting symptoms. The pooled evidence suggests ginger as a safe botanical option for managing nausea and vomiting, but it is important to improve the scientific quality of published meta-analyses in the future.

Effect of a Standardized Ginger Root Powder Regimen on Chemotherapy-Induced Nausea and Vomiting: A Multicenter, Double-Blind, Placebo-Controlled Randomized Trial

BACKGROUND

There is substantial interest in the role of ginger as an adjuvant therapy for chemotherapy-induced nausea and vomiting (CINV). However, available evidence lacks robust methodology.

OBJECTIVE

To assess the effect of adjuvant ginger compared with placebo on chemotherapy-induced nausea-related quality of life (QoL) and CINV-related outcomes.

DESIGN

A parallel, double-blind, placebo-controlled randomized trial with 1:1 allocation was conducted.

PARTICIPANTS/SETTING

One hundred three chemotherapy-naïve adults scheduled to receive moderately to highly emetogenic chemotherapy at two hospitals in Australia were enrolled and analyzed.

INTERVENTION

Four standardized ginger capsules (totaling 84 mg/day active gingerols/shogaols), or placebo, were administered commencing the day of chemotherapy and continuing for 5 days for chemotherapy cycles 1 through 3.

MAIN OUTCOME MEASURES

The primary outcome was chemotherapy-induced nausea-related QoL. Secondary outcomes were vomiting- and CINV-related QoL; anticipatory, acute, and delayed nausea and vomiting; fatigue; nutritional status; depression and anxiety; health-related QoL; and adverse events.

STATISTICAL ANALYSES PERFORMED

Intention-to-treat analysis was performed. Mixed analysis of variance with repeated measures determined differences between groups. The null hypothesis was no difference between groups. After applying a Bonferroni multiple testing correction, evidence against the null hypothesis was considered at P= 0.003.

RESULTS

One hundred three participants (ginger: n = 52; placebo: n = 51) were enrolled and analyzed. There was clinically relevant evidence against the null hypothesis, favoring ginger, in change scores for nausea-related QoL (F[df] = 9.34[1,101]; P = 0.003; partial η2 = 0.09), overall CINV-related QoL (F[df] = 12.26[1,101]; P < 0.001; partial η2 = 0.11), delayed nausea severity (F[df] = 9.46[1,101]; P = 0.003; partial η2 = 0.09), and fatigue (F[df] = 10.11[1,101]; P = 0.002; partial η2 = 0.09). There was a clinically meaningful lower incidence of delayed nausea and vomiting in the ginger group at Cycle 2 (53% vs 75%; P = 0.020 and 4% vs 27%; P = 0.001, respectively) and Cycle 3 (49% vs 79%; P = 0.002 and 2% vs 23%; P = 0.001, respectively). There was a clinically meaningful lower incidence of malnutrition in the ginger group at Cycle 3 (18% vs. 41%; P = 0.032) and in change scores for Patient-Generated Subjective Global Assessment (F[df)] = 4.32[1,100]; P = 0.040; partial η2 = 0.04). Change scores between groups favored ginger for vomiting-related QoL and number of vomiting episodes; however, findings were not clinically meaningful. There was no effect of ginger on anticipatory or acute CINV, health-related QoL, anxiety, or depression. No serious adverse events were reported.

CONCLUSIONS

Ginger supplementation was a safe adjuvant to antiemetic medications for CINV that enhanced QoL during chemotherapy treatment. Future trials are needed to examine dose-dependent responses to verify optimal dosing regimens.

Effect of Ginger Root Powder on Gastrointestinal Bacteria Composition, Gastrointestinal Symptoms, Mental Health, Fatigue, and Quality of Life: A Double-Blind Placebo-Controlled Trial

BACKGROUND

Despite compositional alterations in gastrointestinal microbiota being purported to underpin some of the therapeutic effects of ginger, the effect of a standardized ginger supplement on gut microbiota has not been tested in humans.

OBJECTIVES

To determine the effect of a standardized ginger (Zingiber officinale) root powder, compared to placebo, on gastrointestinal bacteria and associated outcomes in healthy adults.

METHODS

A randomized double-blind placebo-controlled trial allocated participants aged 18 to 30 y to ginger or microcrystalline cellulose (MCC) placebo. The intervention comprised 1.2 g/d of ginger (4 capsules per day totaling 84 mg/d of active gingerols/shogaols) for 14 d following a 1-wk run-in period. Primary outcomes were gastrointestinal community composition, alpha and beta diversity, and differential abundance, measured using 16S rRNA gene sequencing of fecal samples. Secondary outcomes were gastrointestinal symptoms, bowel function, depression, anxiety, stress, fatigue, quality of life, and adverse events.

RESULTS

Fifty-one participants were enrolled and analyzed (71% female; mean age 25 ± 3 y; ginger: n = 29, placebo: n = 22). There was a greater increase in relative abundance of phylum, Actinobacteria, observed following ginger supplementation compared to placebo (U: 145.0; z: -2.1; P = 0.033). Ginger was associated with a greater abundance of the genera Parabacteroides, Bacillus, Ruminococcaceae incertae sedis, unclassified Bacilli, families Defluviitaleaceae, Morganellaceae, and Bacillaceae as well as lower abundance of the genus Blautia and family Sphingomonadaceae (P < 0.05). An improvement in indigestion symptoms was observed with ginger supplementation (U: 196.0; z: -2.4; P = 0.015). No differences between ginger and placebo groups were found for alpha and beta diversity or other secondary outcomes. No moderate or severe adverse events were reported.

CONCLUSIONS

Supplementation with ginger root powder was safe and altered aspects of gastrointestinal bacteria composition; however, it did not change alpha- or beta diversity, bowel function, gastrointestinal symptoms, mood, or quality of life in healthy adults. These results provide further understanding regarding the mechanisms of action of ginger supplementation. This trial was registered in the Australia New Zealand Clinical Trials Registry as ACTRN12620000302954p and the Therapeutic Goods Administration as CT-2020-CTN-00380-1.

Anticancer perspective of 6-shogaol: anticancer properties, mechanism of action, synergism and delivery system

Cancer is a malignant disease that has plagued human beings all the time, but the treatment effect of commonly used anticancer drugs in clinical practice is not ideal by reason of their drug tolerance and Strong adverse reactions to patients. Therefore, it is imperative to find effective and low-toxic anticancer drugs. Many research works have shown that natural products in Chinese herbal medicine have great anticancer potential, such as 6-shogaol, a monomer composition obtained from Chinese herbal ginger, which has been confirmed by numerous in vitro or vivo studies to be an excellent anti-cancer active substance. In addition, most notably, 6-shogaol has different selectivity for normal and cancer cells during treatment, which makes it valuable for further research and clinical development. Therefore, this review focus on the anti-cancer attributes, the mechanism and the regulation of related signaling pathways of 6-shogaol. In addition, its synergy with commonly used anticancer drugs, potential drug delivery systems and prospects for future research are discussed. This is the first review to comprehensively summarize the anti-cancer mechanism of 6-shogaol, hoping to provide a theoretical basis and guiding significance for future anti-cancer research and clinical development of 6-shogaol.

Therapeutic health effects of ginger (Zingiber officinale): updated narrative review exploring the mechanisms of action

Ginger (Zingiber officinale) has been investigated for its potentially therapeutic effect on a range of chronic conditions and symptoms in humans. However, a simplified and easily understandable examination of the mechanisms behind these effects is lacking and, in turn, hinders interpretation and translation to practice, and contributes to overall clinical heterogeneity confounding the results. Therefore, drawing on data from nonhuman trials, the objective for this narrative review was to comprehensively describe the current knowledge on the proposed mechanisms of action of ginger on conferring therapeutic health effects in humans. Mechanistic studies support the findings from human clinical trials that ginger may assist in improving symptoms and biomarkers of pain, metabolic chronic disease, and gastrointestinal conditions. Bioactive ginger compounds reduce inflammation, which contributes to pain; promote vasodilation, which lowers blood pressure; obstruct cholesterol production, which regulates blood lipid profile; translocate glucose transporter type 4 molecules to plasma membranes to assist in glycemic control; stimulate fatty acid breakdown to aid weight management; and inhibit serotonin, muscarinic, and histaminergic receptor activation to reduce nausea and vomiting. Additional human trials are required to confirm the antimicrobial, neuroprotective, antineoplastic, and liver- and kidney-protecting effects of ginger. Interpretation of the mechanisms of action will help clinicians and researchers better understand how and for whom ginger may render therapeutic effects and highlight priority areas for future research.

Plant-Derived Nutraceuticals Involved in Body Weight Control by Modulating Gene Expression

Obesity is the most prevalent health problem in the Western world, with pathological body weight gain associated with numerous co-morbidities that can be the main cause of death. There are several factors that can contribute to the development of obesity, such as diet, sedentary lifestyle, and genetic make-up. Genetic predispositions play an important role in obesity, but genetic variations alone cannot fully explain the explosion of obesity, which is why studies have turned to epigenetics. The latest scientific evidence suggests that both genetics and environmental factors contribute to the rise in obesity. Certain variables, such as diet and exercise, have the ability to alter gene expression without affecting the DNA sequence, a phenomenon known as epigenetics. Epigenetic changes are reversible, and reversibility makes these changes attractive targets for therapeutic interventions. While anti-obesity drugs have been proposed to this end in recent decades, their numerous side effects make them not very attractive. On the other hand, the use of nutraceuticals for weight loss is increasing, and studies have shown that some of these products, such as resveratrol, curcumin, epigallocatechin-3-gallate, ginger, capsaicin, and caffeine, can alter gene expression, restoring the normal epigenetic profile and aiding weight loss.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

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.

Nutritional benefits of ginger for patients with non-communicable diseases

Ginger (Zingiber officinale) is a famous dietary spice rich in bioactive components like gingerols, and it has been used for a long time as food and medicine. Indeed, clinical studies have confirmed the anti-inflammatory and antioxidant properties of ginger. Thus, ginger seems to be an excellent complementary nutritional strategy for non-communicable diseases (NCD) such as obesity, diabetes, cardiovascular disease and chronic kidney disease. This narrative review aims to discuss the possible effects of ginger on the mitigation of common complications such as inflammation, oxidative stress, and gut dysbiosis in NCD.

Zingiber officinale: A Systematic Review of Botany, Phytochemistry and Pharmacology of Gut Microbiota-Related Gastrointestinal Benefits

Ginger (Zingiber officinale Rosc.) is a traditional edible medicinal herb with a wide range of uses and long cultivation history. Fresh ginger (Zingiberis Recens Rhizoma; Sheng Jiang in Chinese, SJ) and dried ginger (Zingiberis Rhizoma; Gan Jiang in Chinese, GJ) are designated as two famous traditional Chinese herbal medicines, which are different in plant cultivation, appearances and functions, together with traditional applications. Previous researches mainly focused on the differences in chemical composition between them, but there was no systematical comparison on the similarity concerning research achievements of the two herbs. Meanwhile, ginger has traditionally been used for the treatment of gastrointestinal disorders, but so far, the possible interaction with human gut microbiota has hardly been considered. This review comprehensively presents similarities and differences between SJ and GJ retrospectively, particularly proposing them the significant differences in botany, phytochemistry and ethnopharmacology, which can be used as evidence for clinical application of SJ and GJ. Furthermore, the pharmacology of gut microbiota-related gastrointestinal benefits has also been discussed in order to explore better ways to prevent and treat gastrointestinal disorders, which can be used as a reference for further research.

Gut Microbiota Variation With Short-Term Intake of Ginger Juice on Human Health

Ginger, a widely used functional food and food additive, little is known about the effect of ginger juice, which is rich in many healthful agents, on healthy humans or on its relationship with gut microbiota composition variation. The aim of this study was to investigate the changes in the gut microbial communities that occur following the supplementation of fresh ginger-derived juice in healthy adults and its potential associations with function. A crossover intervention study in which 123 healthy subjects (63 men and 60 women) consumed fresh ginger juice from Zingiber officinale Rosc. or sterile 0.9% sodium chloride was conducted. 16S rRNA sequencing analyses were applied to characterize gut microbiota variation. We found that ginger juice intervention increased the species number of intestinal flora. A decreased relative abundance of the Prevotella-to-Bacteroides ratio and pro-inflammatory Ruminococcus_1 and Ruminococcus_2 while a tendency toward an increased Firmicutes-to-Bacteroidetes ratio, Proteobacteria and anti-inflammatory Faecalibacterium were found. When we did not consider gender, we found differences in bacterial diversity both in community evenness and in richness caused by ginger intervention. In fact, there were different changes in bacterial α-diversity induced by the ginger juice in men and women. We identified 19 bacterial genera with significant differences between the control group (women) and ginger group (women) and 15 significant differences between the control group (men) and ginger group (men) at the genus level. Our results showed that short-term intake of ginger juice had substantial effects on the composition and function of gut microbiota in healthy people. Moreover, our findings underscored the importance of analyzing both male and female individuals to investigate the effects of ginger on gut microbiota. Additional studies are necessary to confirm these findings.

Microbial-host molecular exchange and its functional consequences in early mammalian life

Molecules from symbiotic microorganisms pervasively infiltrate almost every organ system of a mammalian host, marking the initiation of microbial-host mutualism in utero, long before the newborn acquires its own microbiota. Starting from in utero development, when maternal microbial molecules can penetrate the placental barrier, we follow the different phases of adaptation through the life events of birth, lactation, and weaning, as the young mammal adapts to the microbes that colonize its body surfaces. The vulnerability of early-life mammals is mitigated by maternal detoxification and excretion mechanisms, the protective effects of maternal milk, and modulation of neonatal receptor systems. Host adaptations to microbial exposure during specific developmental windows are critical to ensure organ function for development, growth, and immunity.

The role of gut microbiota for the activity of medicinal plants traditionally used in the European Union for gastrointestinal disorders

ETHNOPHARMACOLOGICAL RELEVANCE

Many medicinal plants have been traditionally used for the treatment of gastrointestinal disorders. According to the monographs published by the Committee on Herbal Medicinal Products (HMPC) at the European Medicines Agency, currently 44 medicinal plants are recommended in the European Union for the treatment of gastrointestinal disorders based on traditional use. The main indications are functional and chronic gastrointestinal disorders, such as functional dyspepsia and irritable bowel syndrome (IBS), and typical effects of these plants are stimulation of gastric secretion, spasmolytic and carminative effects, soothing effects on the gastrointestinal mucosa, laxative effects, adstringent or antidiarrheal activities, and anti-inflammatory effects. A possible interaction with human gut microbiota has hardly been considered so far, although it is quite likely.

AIM OF THE STUDY

In this review, we aimed to identify and evaluate published studies which have investigated interactions of these plants with the gut microbiome.

RESULTS

According to this survey, only a minor portion of the 44 medicinal plants considered in EMA monographs for the treatment of gastrointestinal diseases has been studied so far with regard to potential interactions with gut microbiota. We could identify eight relevant in vitro studies that have been performed with six of these medicinal plants, 17 in vivo studies performed in experimental animals involving seven of the medicinal plants, and three trials in humans performed with two of the plants. The most robust evidence exists for the use of inulin as a prebiotic, and in this context also the prebiotic activity of chicory root has been investigated quite intensively. Flaxseed dietary fibers are also known to be fermented by gut microbiota to short chain fatty acids, leading to prebiotic effects. This could cause a health-beneficial modulation of gut microbiota by flaxseed supplementation. In flaxseed, also other compound classes like lignans and polyunsaturated fatty acids are present, that also have been shown to interact with gut microbiota. Drugs rich in tannins and anthocyanins also interact intensively with gut microbiota, since these compounds reach the colon at high levels in unchanged form. Tannins and anthocyanins are intensively metabolized by certain gut bacteria, leading to the generation of small, bioavailable and potentially bioactive metabolites. Moreover, interaction with these compounds may exert a prebiotic-like effect on gut microbiota. Gut microbial metabolization has also been shown for certain licorice constituents, but their potential effects on gut microbiota still need to be investigated in detail. Only a limited amount of studies investigated the interactions of essential oil- and secoiridoid-containing drugs with human gut microbiota. However, other constituents present in some of these drugs, like curcumin (curcuma), shogaol (ginger), and rosmarinic acid have been shown to be metabolized by human gut microbiota, and preliminary data also indicate potential gut microbiome modulatory effects. To conclude, the interaction with gut microbiota is still not fully investigated for many herbal drugs traditionally used for gastrointestinal disorders, which offers a vast field for future research.

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.

Glucuronidation of [6]-shogaol, [8]-shogaol and [10]-shogaol by human tissues and expressed UGT enzymes: identification of UGT2B7 as the major contributor

Shogaols, mainly [6]-shogaol (6S), [8]-shogaol (8S) and [10]-shogaol (10S), the predominant and characteristic pungent phytochemicals in ginger, are responsible for most of its beneficial effects. However, poor oral bioavailability owing to extensive glucuronidation limits their application. The present study aimed to characterize the glucuronidation pathways of 6S, 8S and 10S by using pooled human liver microsomes (HLM), human intestine microsomes (HIM) and recombinant human UDP-glucosyltransferases (UGTs). The rates of glucuronidation were determined by incubating shogaols with uridine diphosphate glucuronic acid-supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. Reaction phenotyping assays, activity correlation analyses and relative activity factors were performed to identify the main UGT isoforms. As a result, one mono-4′-O-glucuronide was detected after incubating each shogaol with HLM and HIM. Enzymes kinetic analysis demonstrated that glucuronidation of shogaols consistently displayed the substrate inhibition profile, and the liver showed higher metabolic activity for shogaols (CL_int = 1.37–2.87 mL min⁻¹ mg⁻¹) than the intestine (CL_int = 0.67–0.85 mL min⁻¹ mg⁻¹). Besides, reaction phenotyping assays revealed that UGT2B7 displayed the highest catalytic ability (CL_int = 0.47–1.17 mL min⁻¹ mg⁻¹) among all tested UGTs. In addition, glucuronidation of shogaols was strongly correlated with AZT glucuronidation (r = 0.886, 0.803 and 0.871 for glucuronidation of 6S, 8S and 10S, respectively; p < 0.01) in a bank of individual HLMs (n = 9). Furthermore, UGT2B7 contributed to 40.8%, 34.2% and 36.0% for the glucuronidation of 6S, 8S and 10S in HLM, respectively. Taken altogether, shogaols were efficiently metabolized through the glucuronidation pathway, and UGT2B7 was the main contributor to their glucuronidation.

The glucuronidation pathways of shogaols ([6]-shogaol, [8]-shogaol and [10]-shogaol) were characterized in human tissues and recombinant human UDP-glucosyltransferases, and UGT2B7 was identified as the main contributor to their glucuronidation.