Steamed Ginger May Enhance Insulin Secretion through KATP Channel Closure in Pancreatic β-Cells Potentially by Increasing 1-Dehydro-6-Gingerdione Content

The Effects of Body Fat Reduction through the Metabolic Control of Steam-Processed Ginger Extract in High-Fat-Diet-Fed Mice

The prevalence of metabolic syndrome is increasing globally due to behavioral and environmental changes. There are many therapeutic agents available for the treatment of chronic metabolic diseases, such as obesity and diabetes, but the data on their efficacy and safety are lacking. Through a pilot study by our group, Zingiber officinale rhizomes used as a spice and functional food were selected as an anti-obesity candidate. In this study, steam-processed ginger extract (GGE) was used and we compared its efficacy at alleviating metabolic syndrome-related symptoms with that of conventional ginger extract (GE). Compared with GE, GGE (25-100 μg/mL) had an increased antioxidant capacity and α-glucosidase inhibitory activity in vitro. GGE was better at suppressing the differentiation of 3T3-L1 adipocytes and lipid accumulation in HepG2 cells and promoting glucose utilization in C2C12 cells than GE. In 16-week high-fat-diet (HFD)-fed mice, GGE (100 and 200 mg/kg) improved biochemical profiles, including lipid status and liver function, to a greater extent than GE (200 mg/kg). The supplementation of HFD-fed mice with GGE (200 mg/kg) resulted in the downregulation of SREBP-1c and FAS gene expression in the liver. Collectively, our results indicate that GGE is a promising therapeutic for the treatment of obesity and metabolic syndrome.

A Mechanistic Review on Therapeutic Potential of Medicinal Plants and their Pharmacologically Active Molecules for Targeting Metabolic Syndrome

Metabolic syndrome (MetS) therapy with phytochemicals is an emerging field of study with therapeutic potential. Obesity, insulin resistance, high blood pressure, and abnormal lipid profiles are all components of metabolic syndrome, which is a major public health concern across the world. New research highlights the promise of phytochemicals found in foods, including fruits, vegetables, herbs, and spices, as a sustainable and innovative method of treating this illness. Anti-inflammatory, antioxidant, and insulin-sensitizing qualities are just a few of the many positive impacts shown by bioactive substances. Collectively, they alleviate the hallmark symptoms of metabolic syndrome by modulating critical metabolic pathways, boosting insulin sensitivity, decreasing oxidative stress, and calming chronic low-grade inflammation. In addition, phytochemicals provide a multimodal strategy by targeting not only adipose tissue but also the liver, skeletal muscle, and vascular endothelium, all of which have a role in the pathogenesis of MetS. Increasing evidence suggests that these natural chemicals may be useful in controlling metabolic syndrome as a complementary treatment to standard medication or lifestyle changes. This review article emphasizes the therapeutic potential of phytochemicals, illuminating their varied modes of action and their ability to alleviate the interconnected causes of metabolic syndrome. Phytochemical-based interventions show promise as a novel and sustainable approach to combating the rising global burden of metabolic syndrome, with the ultimate goal of bettering public health and quality of life.

Phenylalkyl Glycosides from the Flowers of Brugmansia arborea L. and Their Radical Scavenging Effect and Protective Effect on Pancreatic Islets Damaged by Alloxan in Zebrafish (Danio rerio) Larvae

The study aimed to investigate the antioxidant and antidiabetic activity of Brugmansia arborea L. flower extracts, solvent fractions, and isolated compounds. B. arborea L flowers were extracted with aqueous methanol, and concentrated extract was successively partitioned into EtOAc, n-BuOH, and H2O fractions. Repeated silica gel and octadecyl silica gel column chromatographies for EtOAc and n-BuOH fractions led to the isolation of a new phenylalkyl glycoside (6), along with five known ones. Several spectroscopic data led to the structure determination of one new phenylalky glycoside as brugmansioside C (named) (6) and five known ones as benzyl-O-β-D-glucopyranoside (1), benzyl-O-β-D-glucosyl-(1→6)-β-D-glucopyranoside (2), 2-phenylethyl-O-β-D-glucopyranoside (3), 2-phenylethyl-O-β-D-glucosyl-(1→6)-β-D-glucopyranoside (4), and 3-phenylpropyl-O-β-D-glucopyranoside (5). The five known ones (1-5) were isolated from B. arborea flowers for the first time in this study. The extract, solvent fractions, and all isolated compounds showed radical scavenging activities using ABTS radical, and EtOAc fraction showed the highest scavenging capacity, whereas compounds 2, 4, and 6 did not display the capacity to use the DPPH radical. The extract, solvent fractions, and all isolated compounds showed a protective effect on pancreatic islets damaged by alloxan treatment in zebrafish larvae. The pancreatic islet size treated with EtOAc, n-BuOH fractions, and all compounds significantly increased by 64.0%, 69.4%, 82.0%, 89.8%, 80.0%, 97.8%, 103.1%, and 99.6%, respectively, compared to the alloxan-induced group. These results indicate that B. arborea flowers and their isolated compounds are useful as potential antioxidant and antidiabetic agents.

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.

Ameliorative Effects of Flavonoids from Platycodon grandiflorus Aerial Parts on Alloxan-Induced Pancreatic Islet Damage in Zebrafish

Platycodon grandiflorus (balloon flower), used as a food reserve as well as in traditional herbal medicine, is known for its multiple beneficial effects. In particular, this plant is widely used as a vegetable in Republic of Korea. We examined the ameliorative effects of P. grandiflorus on alloxan-induced pancreatic islet damage in zebrafish. The aerial part treatment led to a significant recovery in pancreatic islet size and glucose uptake. The efficacy of the aerial part was more potent than that of the root. Eight flavonoids (1-8) were isolated from the aerial part. Structures of two new flavone glycosides, designated dorajiside I (1) and II (2), were elucidated to be luteolin 7-O-α-L-rhamno-pyranosyl (1 → 2)-(6-O-acetyl)-β-D-glucopyranoside and apigenin 7-O-α-L-rhamnopyranosyl (1 → 2)-(6-O-acetyl)-β-D-glucopyranoside, respectively, by spectroscopic analysis. Compounds 1, 3, 4 and 6-8 yielded the recovery of injured pancreatic islets in zebrafish. Among them, compound 7 blocked K_ATP channels in pancreatic β-cells. Furthermore, compounds 3, 4, 6 and 7 showed significant changes with respect to the mRNA expression of GCK, GCKR, GLIS3 and CDKN2B compared to alloxan-induced zebrafish. In conclusion, the aerial part of P. grandiflorus and its constituents conferred a regenerative effect on injured pancreatic islets.

Modulatory Effect of Medicinal Plants and Their Active Constituents on ATP-Sensitive Potassium Channels (KATP) in Diabetes

Hyperglycemia, which is a chronic metabolic condition caused by either a defect in insulin secretion or insulin resistance, is a hallmark of diabetes mellitus (DM). Sustained hyperglycemia leads to the onset and development of many health complications. Despite the number of available antidiabetic medications on the market, there is still a need for novel treatment agents with increased efficacy and fewer adverse effects. Many medicinal plants offer a rich supply of bioactive compounds that have remarkable pharmacological effects with less toxicity and side effects. According to published evidence, natural antidiabetic substances influence pancreatic β-cell development and proliferation, inhibit pancreatic β-cell death, and directly increase insulin output. Pancreatic ATP-sensitive potassium channels play an essential role in coupling glucose metabolism to the secretion of insulin. Although much of the literature is available on the antidiabetic effects of medicinal plants, very limited studies discuss their direct action on pancreatic KATP. The aim of this review is to focus on the modulatory effects of antidiabetic medicinal plants and their active constituents on pancreatic KATP. The KATP channel should be regarded as a key therapeutic milestone in the treatment of diabetes. Therefore, continuous research into the interaction of medicinal plants with the KATP channel is crucial.

The Effect of Ginger (Zingiber officinale Roscoe) Aqueous Extract on Postprandial Glycemia in Nondiabetic Adults: A Randomized Controlled Trial

Ginger has shown beneficial effects on blood glucose control due to its antioxidant and anti-inflammatory properties. The present study investigated the effect of ginger aqueous extract on postprandial glucose levels in nondiabetic adults and characterized its antioxidant activity. Twenty-four nondiabetic participants were randomly assigned into two groups (NCT05152745), the intervention group (n = 12) and the control group (n = 12). Both groups were administered 200 mL of an oral glucose tolerance test (OGTT), after which participants in the intervention group ingested 100 mL of ginger extract (0.2 g/100 mL). Postprandial blood glucose was measured while fasting and after 30, 60, 90, and 120 min. The total phenolic content, flavonoid content, and antioxidant activity of ginger extract were quantified. In the intervention group, the incremental area under the curve for glucose levels decreased significantly (p < 0.001) and the maximum glucose concentration significantly reduced (p < 0.001). The extract possessed a polyphenolic content of 13.85 mg gallic acid equivalent/L, a flavonoid content of 3.35 mg quercetin equivalent/L, and a high superoxide radical inhibitory capacity (45.73%). This study showed that ginger has a beneficial effect on glucose homeostasis under acute conditions and encourages the use of ginger extract as a promising source of natural antioxidants.

Impact of Thermal Processing on the Selected Biological Activities of Ginger Rhizome-A Review

Ginger (Zingiber officinale Rosc.) is a spice, medicinal and cosmetic plant that has been known for centuries. It can be used in dried, fresh, marinated or candied form, and is also an essential ingredient in well-known curry blends. Ginger rhizomes are often freeze-dried as the first step in the preparation of the raw material. Many studies have proved that the composition and biological activity of ginger changes due to thermal processing. Therefore, the aim of the review was to summarize the scientific results on the impact of traditional and unconventional methods of the heat treatment of ginger rhizomes and their influence on the antioxidant and other selected biological activities of the plant. The review of the available scientific data is inconclusive, and it is hard to state unequivocally whether the thermal treatment of the raw material increases or decreases biological activity. Based on the presented literature review, it can be concluded that traditional cooking and microwave processing in general decrease the antioxidant activity of the ginger rhizome, whereas frying, autoclaving, blanching or traditional drying in the sun mostly lead to a significant increase in ginger activity. Interesting data were presented in the works describing the freeze-drying process during which the antioxidant potential of ginger increased.

Impact of Thermal Processing on the Composition of Secondary Metabolites of Ginger Rhizome-A Review

Ginger (Zingiber officinale Rosc.) is both a commonly used spice, and an ingredient of various dietary supplements and medications. Its diverse applications result from the range of health benefits that this plant brings thanks to the presence of active compounds (secondary metabolites) in the matrix. Even if several studies underline a stronger pharmacological activity of fresh ginger rhizomes, the unprocessed plant is relatively rarely used. Ginger rhizomes are subjected to thermal processing, such as boiling, blanching, steam drying and others, at different temperature and time settings. Additionally, freeze-drying of the rhizomes is used as the first step in the preparation of raw material. It was proved that the composition of secondary metabolites of the Zingiber officinale rhizome changes upon the influence of temperature. Therefore, the aim of the review was to put together scientific results on the impact of traditional and unconventional methods of heat treatment on ginger rhizomes and to show the compositional differences that they induce in the plant matrix. Variations in the content and the transformation of some compounds into other metabolites will be also discussed, with particular attention paid to two major groups of secondary metabolites present in the plant, namely, phenolics and terpenes.

The ginger extract could improve diabetic retinopathy by inhibiting the expression of e/iNOS and G6PDH, apoptosis, inflammation, and angiogenesis

Diabetic retinopathy is a complication of diabetes, caused by high blood sugar levels damaging the retina. It is the result of damage to the small blood vessels and neurons of the retina. Ginger and its phytochemical compounds can improve oxidative damage and inflammation. However, the effects of this plant on ocular expression G6PDH and e/iNOS, eye cell apoptosis, and angiogenesis are not well known in this tissue. Therefore, the aim of this study was to evaluate the therapeutic potential of ginger extract on rats with type 2 diabetic retinopathy. Thirty-two Wistar rats were randomly divided into four controlled and treated groups. The serum level of metabolic factors such as lipid profiles, insulin and glucose, and the level of oxidative biomarkers along with the TNF-α level in eye tissue were measured. The expression of NF-κB, VEGF, BAX, Bcl-2, caspase-3, e/iNOS, and G6PDH in eye tissue was measured. Serum levels of lipid profiles, glucose, and insulin, oxidative and inflammatory markers were significantly increased in the diabetic group compared to control. While, treatment with ginger extract could significantly improve these factors in diabetic rats. Moreover, the ocular expression of e/iNOS, G6PDH, VEGF, NF-κB, and genes involved in apoptosis was changed in diabetic rats. However, treatment with ginger extract could ameliorate these changes in the diabetic-treated group. It can be concluded that ginger extract could improve diabetic retinopathy by inhibiting oxidative damage, inflammation, iNOS, VEGF, apoptosis, and improving eNOS and G6PDH. PRACTICAL APPLICATIONS: Microvascular complications of diabetes such as retinopathy can be one of the main causes of disability in people with diabetes. Chronic hyperglycemia, oxidative stress, inflammation, and apoptosis cause diabetic retinopathy through retinal damage. Ginger, on the other hand, is an available, inexpensive, and uncomplicated medicinal plant that contains more than 20 different phytochemicals, such as gingerol and shogaol, which have anti-inflammatory, antioxidant, antihypertensive, hypoglycemic, and hypolipidemic properties. The results of our study showed well that the ginger extract could improve diabetic retinopathy by inhibiting the expression of e/iNOS and G6PDH and oxidative damage, apoptosis, inflammation, and angiogenesis. Therefore, ginger and its compounds can be a good option to improve the complications of diabetes.

Plants of the Genus Zingiber: A Review of Their Ethnomedicine, Phytochemistry and Pharmacology

Plant of the genus Zingiber (Zingiberaceae) have primarily distributed in subtropical and tropical Asia, South America and Africa. The species of this genus have been widely used as food and in folk with a long history for treating various diseases. Reports related to the phytochemistry and phytochemistry of Zingiber species are numerous, but articles on the summary of the genus Zingiber remain scarce. This review aims at presenting comprehensive information about the genus Zingiber and providing a reference for the future application by systematically reviewing the literature from 1981 to 2020. Currently, a total of 447 phytochemical constituents have been isolated and identified from this genus, in which volatile oils, diarylheptanoids, gingerols, flavonoids and terpenoids are the major components. Gingerols, which are the main functional components, are the spicy and aromatic ingredients in the Zingiber species. Extracts and single compounds from Zingiber plants have been discovered to possess numerous biological functions, such as anti-inflammatory, anticancer, antimicrobial, larvicidal, antioxidant and hypoglycemic activities. This review provides new insights into the ethnomedicine, phytochemistry and pharmacology of the genus Zingiber and brings to the forefront key findings on the functional components of this genus in food and pharmaceutical industries.

Steamed Ginger Extract Exerts Anti-inflammatory Effects in Helicobacter pylori-infected Gastric Epithelial Cells through Inhibition of NF-κB

Ginger (Zingiber officinale) has traditionally been used as a treatment for inflammatory diseases in the Asian region. Recently, anti-inflammatory effects of steamed ginger extract (GGE03) have been reported, but its association with Helicobacter pylori (H. pylori)-induced gastritis has not been investigated. The purpose of this study was to assess the anti-inflammatory activity of GGE03 in H. pylori-infected gastric epithelial cells. Our studies revealed that the GGE03 suppressed the growth of H. pylori. GGE03 markedly reduced the expression of the H. pylori-induced pro-inflammatory cytokines including interleukin (IL)-8, TNF-α, IL-6, inducible NOS (iNOS) and IFN-γ. We also demonstrated that GGE03 treatment inhibited the H. pylori-activated NF-κB signaling pathway. In addition, the treatment with GGE03 significantly attenuated nitric oxide production and myeloperoxidase activity in H. pylori-infected gastric epithelial cells. These anti-inflammatory effects of GGE03 were more effective than ginger extract. Finally, we investigated the minimum effective concentration of GGE03 to inhibit H. pylori-induced inflammation. Our findings suggest that GGE03 not only inhibits the growth of H. pylori, but also attenuates H. pylori-induced inflammation.

Simultaneous Tests of Theaflavin-3,3'-digallate as an Anti-Diabetic Drug in Human Hepatoma G2 Cells and Zebrafish (Danio rerio)

Theaflavin-3,3′-digallate (TF3) is the most important theaflavin monomer in black tea. TF3 was proved to reduce blood glucose level in mice and rats. However, the elaborate anti-diabetic mechanism was not well elucidated. In this work, human hepatoma G2 (HepG2) cells and zebrafish (Danio rerio) were used simultaneously to reveal anti-diabetic effect of TF3. The results showed that TF3 could effectively rise glucose absorption capacity in insulin-resistant HepG2 cells and regulate glucose level in diabetic zebrafish. The hypoglycemic effect was mediated through down-regulating phosphoenolpyruvate carboxykinase and up-regulating glucokinase. More importantly, TF3 could significantly improve β cells regeneration in diabetic zebrafish at low concentrations (5 μg/mL and 10 μg/mL), which meant TF3 had a strong anti-diabetic effect. Obviously, this work provided the potential benefit of TF3 on hypoglycemic effect, regulating glucose metabolism enzymes, and protecting β cells. TF3 might be a promising agent for combating diabetes.

Aurones and Flavonols from Coreopsis lanceolata L. Flowers and Their Anti-Oxidant, Pro-Inflammatory Inhibition Effects, and Recovery Effects on Alloxan-Induced Pancreatic Islets in Zebrafish

(1) Background: Many flavonoids have been reported to exhibit pharmacological activity; a preparatory study confirmed that Coreopsis lanceolata flowers (CLFs) contained high flavonoid structure content; (2) Methods: CLFs were extracted in aqueous methanol (MeOH:H₂O = 4:1) and fractionated into acetic ester (EtOAc), normal butanol (n-BuOH), and H₂O fractions. Repeated column chromatographies for two fractions led to the isolation of two aurones and two flavonols; (3) Results: Four flavonoids were identified based on a variety of spectroscopic data analyses to be leptosidin (1), leptosin (2), isoquercetin (3), and astragalin (4), respectively. This is the first report for isolation of 2–4 from CLFs. High-performance liquid chromatography (HPLC) analysis determined the content levels of compounds 1–4 in the MeOH extract to be 2.8 ± 0.3 mg/g (1), 17.9 ± 0.9 mg/g (2), 3.0 ± 0.2 mg/g (3), and 10.9 ± 0.9 mg/g (4), respectively. All isolated compounds showed radical scavenging activities and recovery activities in Caco-2, RAW264.7, PC-12, and HepG2 cells against reactive oxygen species. MeOH extract, EtOAc fraction, and 1–3 suppressed NO formation in LPS-stimulated RAW 264.7 cells and decreased iNOS and COX-2 expression. Furthermore, all compounds recovered the pancreatic islets damaged by alloxan treatment in zebrafish; (4) Conclusions: The outcome proposes 1–4 to serve as components of CLFs in standardizing anti-oxidant, pro-inflammatory inhibition, and potential anti-diabetic agents.

p53 Rather Than β-Catenin Mediated the Combined Hypoglycemic Effect of Cinnamomum cassia (L.) and Zingiber officinale Roscoe in the Streptozotocin-Induced Diabetic Model

Background: The antioxidant, hypoglycemic, and insulin-enhancing effects of ginger and cinnamon were previously confirmed in experimental and human studies, while the combined effect of ginger and cinnamon was not thoroughly investigated until now.

Objectives: This study was designed to assess the antidiabetic effect of combined administration of ginger (Zingiber officinale Roscoe) and cinnamon (Cinnamomum cassia L.) in streptozotocin (STZ)-induced diabetic rats compared to metformin and to explain the mechanism behind this effect.

Materials and methods: STZ was utilized to induce diabetes mellitus in male Sprague–Dawley rats. Assessments of fasting blood glucose level (BGL), the total antioxidant capacity (TAC), serum insulin, HOMA-IR, and HOMA–β cells were performed. Pancreatic gene expression of β-catenin and p53 was assessed using RT-PCR. Assessment of histopathological alterations of pancreatic islet cells was performed using routine and immunohistochemical techniques.

Results: BGL significantly decreased (p = 0.01), while serum insulin and TAC significantly increased (p < 0.001) in both metformin- and ginger plus cinnamon–treated groups compared to the untreated diabetic group. HOMA–β cell index significantly increased (p = 0.001) in ginger plus cinnamon, indicating their enhancing effect on insulin secretion in diabetic conditions. p53 gene expression was significantly upregulated (p < 0.001), while β-catenin was insignificantly downregulated (p = 0.32) in ginger plus cinnamon–treated groups. Insulin immunoexpression in β cells significantly increased (p = 0.001, p = 0.004) in metformin- and ginger plus cinnamon–treated groups, respectively.

Conclusions: The combined administration of ginger and cinnamon has a significant hypoglycemic and antioxidant effect in STZ-induced diabetes mostly through enhancing repair of islet cells mediated via upregulation of pancreatic p53 expression. Therefore, testing this effect in diabetic patients is recommended.

Antiulcer Activity of Steamed Ginger Extract against Ethanol/HCl-Induced Gastric Mucosal Injury in Rats

Ginger (Zingiber officianale), the most widely consumed species, is traditionally used as a folk medicine to treat some inflammatory diseases in China and Korea. However, the functional activity of steamed ginger extract on gastric ulcers has not been previously explored. The present study aimed to investigate antiulcer activity of steamed ginger extract (GGE03) against ethanol (EtOH)/HCl-induced gastric ulcers in a rat model. GGE03 (100 mg/kg) was orally administered for 14 days to rats before oral intubation of an EtOH/HCl mixture to induce gastric damage. Pretreatment with GGE03 markedly protected the formation of microscopic pathological damage in the gastric mucosa. Further, administration of GGE03 significantly increased mucosal total nitrate/nitrite production in gastric tissues, and elevated total GSH content, catalase activity and superoxide dismutase (SOD) expression as well as decreasing lipid peroxidation and myeloperoxidase (MPO) activity. Underlying protective mechanisms were examined by assessing inflammation-related genes, including nuclear factor-κB (NF-κB), prostaglandin E2 (PGE2), and pro-inflammatory cytokines levels. GGE03 administration significantly reduced the expression of NF-κB and pro-inflammatory cytokines. Our findings suggest that GGE03 possesses antiulcer activity by attenuating oxidative stress and inflammatory responses.