Ginger Bioactives: A Comprehensive Review of Health Benefits and Potential Food Applications

Ginger is an herbaceous and flowering plant renowned for its rhizome, which is widely employed as both a spice and an herb. Since ancient times, ginger has been consumed in folk medicine and traditional cuisines for its favorable health effects. Different in vitro and in vivo studies have disclosed the advantageous physiological aspects of ginger, primarily due to its antioxidant, anti-inflammatory, antimicrobial, and anti-carcinogenic properties. These health-promoting features are linked to the variety of bioactive compounds that are present in ginger. Following the advancement in consumer awareness and the industrial demand for organic antioxidants and functional ingredients, the application of ginger and its derivatives has been broadly investigated in a wide range of food products. The prominent features transmitted by ginger into different food areas are antioxidant and nutraceutical values (bakery); flavor, acceptability, and techno-functional characteristics (dairy); hedonic and antimicrobial properties (beverages); oxidative stability, tenderization, and sensorial attributes (meat); and shelf life and sensorial properties (film, coating, and packaging). This review is focused on providing a comprehensive overview of the tendencies in the application of ginger and its derivatives in the food industry and concurrently briefly discusses the beneficial aspects and processing of ginger.

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.

Gingerols synergize with anthocyanins to induce antioxidant activity in vitro

Oxidative stress caused by free radicals contributes to the pathogenesis of multiple chronic health conditions. Phytochemicals protect against oxidative stress; however, low bioavailability from dietary sources limits their health benefits. This study aimed to assess the effects of anthocyanins and gingerols' combination on the cellular antioxidant response of Caco-2 cells against oxidative stress. A strong synergism was observed for anthocyanin-gingerol (Ac-G) w/w combined ratios of 8:1 and 2:1 (dosages of (1 + 0.125) and (1 + 0.5) μg/mL) in the cellular antioxidant activity (CAA) and cytoprotective effects, with synergistic effect indicator (SE) values of 1.41 and 1.61, respectively. The synergism of Ac-G combinations promoted cellular antioxidant defense systems and cytoprotective effects by reducing the induced GPx enzyme activity, protecting SOD enzyme activity, reducing cellular ROS generation, increasing glutathione content, and inhibiting lipid peroxidation. Thus, Ac-G combinations showed potential in supporting the endogenous antioxidant systems to protect cells from oxidation and restore physiological redox status. The Ac-G formulation is a promising healthy option that can be developed into functional foods or nutraceutical products. Furthermore, it could help address the low bioavailability of these phenolics, as higher effects were achieved when combining the same doses.

Immunomodulatory effects and mechanisms of the extracts and secondary compounds of Zingiber and Alpinia species: a review

Zingiber and Alpinia species (family: Zingiberaceae) are popularly used in food as spices and flavoring agents and in ethnomedicine to heal numerous diseases, including immune-related disorders. However, their ethnomedicinal uses have not been sufficiently supported by scientific investigations. Numerous studies on the modulating effects of plants and their bioactive compounds on the different steps of the immune system have been documented. This review aimed to highlight up-to-date research findings and critically analyze the modulatory effects and mechanisms of the extracts and secondary compounds of several Zingiber and Alpinia species, namely, Zingiber officinale Roscoe, Z. cassumunar Roxb., Z. zerumbet (L.) Roscoe ex Sm., Alpinia galanga Linn., A. conchigera Griff, A. katsumadai Hayata, A. oxyphylla Miq., A. officinarum Hance, A. zerumbet (Pers.) Burtt. et Smith, and A. purpurata (Viell.) K. Schum. on the immune system, particularly via the inflammation-related signaling pathways. The immunomodulating activities of the crude extracts of the plants have been reported, but the constituents contributing to the activities have mostly not been identified. Among the extracts, Z. officinale extracts were the most investigated for their in vitro, in vivo, and clinical effects on the immune system. Among the bioactive metabolites, 6-, 8-, and 10-gingerols, 6-shogaol, and zerumbone from Zingiber species and cardamomin, 1'-acetoxychavicol acetate, yakuchinone, rutin, 1,8-cineole, and lectin from Alpinia species have demonstrated strong immunomodulating effects. More experimental studies using cell and animal models of immune-related disorders are necessary to further understand the underlying mechanisms, together with elaborate preclinical pharmacokinetics, pharmacodynamics, bioavailability, and toxicity studies. Many of these extracts and secondary metabolites are potential candidates for clinical development in immunomodulating agents or functional foods to prevent and treat chronic inflammatory disorders.

(Lepidoptera: Noctuidae)

The discovery of eco-friendly plant-based insecticides is currently booming in research with an attempt to replace synthetic chemical insecticides causing tremendous adverse effects. The present work studied the insecticidal potential of ginger, an important medicinal plant. Four crude extracts from Zingiber officinale rhizomes were evaluated for their contact toxicity against second instars of Spodoptera litura, Spodoptera exigua and Spodoptera frugiperda using the topical application. The hexane extract exhibited the strongest toxicity to S. exigua with the LD50 of 9.92 and 8.40 µg/larva at 24 and 48 h posttreatment, respectively, followed by S. frugiperda. Comparative toxicity of the most abundant secondary metabolites from the hexane extract, gingerols and shogaols, against both insects concluded that 8-shogaol (5) was identified as the most active compound against S. frugiperda with the LD50 of 7.68 and 3.96 µg/larva at 24 and 48 h posttreatment, respectively.

Using Metabolomics to Identify the Exposure and Functional Biomarkers of Ginger

Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics has become an important tool to increase our understanding of how diet affects human health. However, public and commercial mass spectral libraries of dietary metabolites are limited, resulting in the greatest challenge in converting mass spectrometry data into biological insights. In this study, we constructed an LC-MS/MS ginger library as an example to demonstrate the importance of dietary libraries for discovering food biomarkers. The functional and exposure biomarkers of ginger were investigated using plasma samples from mice treated with control and ginger extract diets. Our results showed clear discrimination between the metabolome of mice on normal and ginger extract diets. Using the in-house ginger library, we identified 20 ginger metabolites that can be used as exposure biomarkers of ginger. However, without the LC-MS/MS ginger library, none of the ginger metabolites could be accurately identified based on online mass databases. In addition, ginger treatment significantly impacts the endogenous metabolome, especially the purine metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis. Overall, we demonstrated that the construction of LC-MS/MS spectra dietary libraries would enhance the ability to identify potential dietary biomarkers and correlate potential health benefits associated with food consumption.

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.

A Rapid Non-Destructive Hyperspectral Imaging Data Model for the Prediction of Pungent Constituents in Dried Ginger

Ginger is best known for its aromatic odour, spicy flavour and health-benefiting properties. Its flavour is derived primarily from two compound classes (gingerols and shogaols), with the overall quality of the product depending on the interaction between these compounds. Consequently, a robust method for determining the ratio of these compounds would be beneficial for quality control purposes. This study investigated the feasibility of using hyperspectral imaging to rapidly determine the ratio of 6-gingerol to 6-shogoal in dried ginger powder. Furthermore, the performance of several pre-processing methods and two multivariate models was explored. The best-performing models used partial least squares regression (PSLR) and least absolute shrinkage and selection operator (LASSO), using multiplicative scatter correction (MSC) and second derivative Savitzky–Golay (2D-SG) pre-processing. Using the full range of wavelengths (~400–1000 nm), the performance was similar for PLSR (R² ≥ 0.73, RMSE ≤ 0.29, and RPD ≥ 1.92) and LASSO models (R² ≥ 0.73, RMSE ≤ 0.29, and RPD ≥ 1.94). These results suggest that hyperspectral imaging combined with chemometric modelling may potentially be used as a rapid, non-destructive method for the prediction of gingerol-to-shogaol ratios in powdered ginger samples.

Ginger (Zingiber officinale Roscoe) as a nutraceutical: Focus on the metabolic, analgesic, and antiinflammatory effects

Ginger (from the rizhome of Zingiber officinale Roscoe) has been widely used in ethnomedicine for the cure of several ailments. Main active ingredients include phenolic compounds named gingerols. In modern phytotherapy, ginger preparations are predominantly used to counteract nausea and vomiting in pregnant women. However, a number of other pharmacological actions of potential therapeutic interest, which might broaden the spectrum of its clinical use, have been reported. This focused review aims at giving a shot on the antinflammatory, analgesic, and metabolic actions of Zingiber officinale preparations, with a discussion on the clinical applications in knee osteoarthritis, dysmenorrhea, type‐2 diabetes, hyperlipidemia, overweight, and obesity.

Alternative processing technology for the preparation of carbonized Zingiberis Rhizoma by stir-frying with sand

Context: Carbonized ginger, a type of charry herb, has been used as a hemostatic medicine since ancient times. However, there are some serious problems such as inhomogeneous heating and emitting smoke during processing with traditional stir-frying method.Objective: To investigate the feasibility to obtain carbonized ginger by stir-frying with sand instead of stir-frying method.Materials and methods: Dried-ginger (100 g) was processed by stir-frying for 30 min at 270 ± 10 °C, or by stir-frying with sand (1:10, w/w) for 8 min at 240 ± 5 °C. The HPLC fingerprint was established for two samples. The adsorption capacity and major components including tannins, gingerols, shogaols and gingerone were quantitated by UV and HPLC, respectively. The hemostatic effect by prothrombin time (PT) and activated partial thromboplastin time (APTT) was evaluated in vitro.Results: The similarity of the two samples for HPLC fingerprints was >0.93. The sand-fried samples showed significantly higher adsorption capacity compared with the stir-fried samples (4.915 vs. 4.593 mg/g; p < 0.05) and higher contents of major components (4.698 vs. 3.930 mg/g, 1.352 vs. 1.144 mg/g, 2.419 vs. 2.095 mg/g, 0.666 vs. 0.568 mg/g and 1.083 vs. 0.911 mg/g for tannins, gingerone, 6-shogaol, 8-shogaol and 10-shogaol, respectively; p < 0.05); while no significant differences were seen for 6-gingerol, 8-gingerol and 10-gingerol (p > 0.05). The PT and APTT values were similar between the stir-fried and sand-fried test groups and significantly lower compared to controls (p < 0.05).Conclusions: The carbonizing process by stir-frying with sand is superior to the stir-frying method for carbonized ginger.

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.

Pharmacokinetics and Tissue Distribution of Gingerols and Shogaols from Ginger (Zingiber officinale Rosc.) in Rats by UPLC⁻Q-Exactive⁻HRMS

Gingerols and shogaols are recognized as active ingredients in ginger and exhibit diverse pharmacological activities. The preclinical pharmacokinetics and tissue distribution investigations of gingerols and shogaols in rats remain less explored, especially for the simultaneous analysis of multi-components. In this study, a rapid, sensitive, selective, and reliable method using an Ultra-Performance Liquid Chromatography Q-Exactive High-Resolution Mass Spectrometer (UPLC-Q-Exactive⁻HRMS) was established and validated for simultaneous determination of eight compounds, including 6-gingerol, 6-shogaol, 8-gingerol, 8-shogaol, 10-gingerol, 10-shogaol, Zingerone, and 6-isodehydrogingenone in plasma and tissues of rats. The analytes were separated on a Syncronis C18 column (100 × 2.1 mm, 1.7 µm) using a gradient elution of acetonitrile and 0.1% formic acid in water at a flow rate of 0.25 mL/min at 30 °C. The method was linear for each ingredient over the investigated range with all correlation coefficients greater than 0.9910. The lowest Lower Limit of quantitation (LLOQ) was 1.0 ng/mL. The intra- and inter-day precisions (Relative Standard Deviation, RSD%) were less than 12.2% and the accuracy (relative error, RE%) ranged from -8.7% to 8.7%. Extraction recovery was 91.4⁻107.4% and the matrix effect was 86.3⁻113.4%. The validated method was successfully applied to investigate the pharmacokinetics and tissue distribution of eight components after oral administration of ginger extract to rats. These results provide useful information about the pharmacokinetics and biodistribution of the multi-component bioactive ingredients of ginger in rats and will contribute to clinical practice and the evaluation of the safety of a Chinese herbal medicine.

[Antagonism mechanism of gingerols against inflammatory effect of toxic raphides from Pinella pedatisecta]

This study was to investigate the mechanism of gingerols antagonizing the inflammatory effect of toxic raphides from Pinella pedatisecta. Mice peritonitis models induced by toxic raphides from P. pedatisecta were applied to observe the effect of gingerols on inflammatory mediators PGE2 in the exudates of abdominal inflammation in mice; rats peritoneal macrophage in vitro culture models were adopted to study the anti-inflammatory effects of gingerol against toxic raphides, with TNF-α and IL-1β in supernatant as indexes. Scanning electron microscopy was used to observe the changes in surface morphology of macrophages treated by raphides and gingerols. Macrophages-neutrophils co-cultured models were used to study the antagonism of gingerols against the effect of toxic raphides' stimulation on neutrophils migration. Results showed that gingerols could significantly inhibit the production of PGE2 in the exudates of abdominal inflammation induced by toxic raphides from P. pedatisecta in mice. Gingerols could significantly inhibit the toxic raphides from P. pedatisecta to induce the release of inflammatory factors, with certain dose dependence. Scanning electron microscopy showed that gingerols could significantly inhibit phagocytosis of macrophages, cytomembrane injury, and neutrophils migration induced by toxic raphides from P. pedatisecta. The results showed that the antagonism mechanism of gingerols against the toxic raphides from P. pedatisecta may be associated with inhibiting the pro-inflammatory toxicity including macrophage activation, inflammatory factors release, and neutrophils migration.

Comparison of Inhibitory Capacities of 6-, 8- and 10-Gingerols/Shogaols on the Canonical NLRP3 Inflammasome-Mediated IL-1β Secretion

Endogenous noninfectious substances that mediate the nucleotide oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation and interleukin (IL)-1β secretion causes inappropriate sterile inflammation and is implicated in the pathogenesis of several chronic diseases, such as type 2 diabetes mellitus, gout, atherosclerosis and Alzheimer’s disease. Consequently, dietary phytochemicals exhibiting capacities to suppress canonical NLRP3 inflammasome-mediated IL-1β secretion can be a reliable supplement to prevent such diseases. The purpose of this study was to investigate and compare the inhibitory effects of ginger phytochemicals, including 6-, 8- and 10-gingerols/shogaols on the canonical NLRP3 inflammasome-mediated IL-1β secretion in THP-1 macrophages with ordered stimulations of lipopolysaccharide (LPS) and adenosine 5′-triphosphate (ATP). At 20 μM, the 10-gingerol and all the shogaols significantly inhibited canonical IL-1β secretion. The shogaols had a more potent inhibitory capacity than that of corresponding gingerols. Increase of alkyl chain length impacted negatively the inhibitory activity of shogaols. Additionally, these effective ginger phytochemicals not only inhibited the LPS-primed expression of pro-IL-1β and NLRP3, but also decreased ATP-activated caspase-1. The results demonstrated that ginger phytochemicals, especially the most potent, 6-shogaol, might be promising for developing as an inhibitor of the canonical NLRP3 inflammasome-mediated IL-1β secretion and further applied in prevention of NLRP3 inflammasome-associated diseases.

Nine New Gingerols from the Rhizoma of Zingiber officinale and Their Cytotoxic Activities

Nine new gingerols, including three 6-oxo-shogaol derivatives [(Z)-6-oxo-[6]-shogaol (1), (Z)-6-oxo-[8]-shogaol (2), (Z)-6-oxo-[10]-shogaol (3)], one 6-oxoparadol derivative [6-oxo-[6]-paradol (4)], one isoshogaol derivative [(E)-[4]-isoshogaol (5)], and four paradoldiene derivatives [(4E,6Z)-[4]-paradoldiene (8), (4E,6E)-[6]-paradoldiene (9), (4E,6E)-[8]-paradoldiene (10), (4E,6Z)-[8]-paradoldiene (11)], together with eight known analogues, were isolated from the rhizoma of Zingiber officinale. Their structures were elucidated on the basis of spectroscopic data. It was noted that the isolation of 6-oxo-shogaol derivatives represents the first report of gingerols containing one 1,4-enedione motif. Their structures were elucidated on the basis of spectroscopic and HRESIMS data. All the new compounds were evaluated for their cytotoxic activities against human cancer cells (MCF-7, HepG-2, KYSE-150).

Quantitation of Gingerols in Human Plasma by Newly Developed Stable Isotope Dilution Assays and Assessment of Their Immunomodulatory Potential

In a pilot study with two volunteers, the main pungent and bioactive ginger (Zingiber officinale Roscoe) compounds, the gingerols, were quantitated in human plasma after ginger tea consumption using a newly established HPLC-MS/MS(ESI) method on the basis of stable isotope dilution assays. Limits of quantitation for [6]-, [8]-, and [10]-gingerols were determined as 7.6, 3.1, and 4.0 nmol/L, respectively. The highest plasma concentrations of [6]-, [8]-, and [10]-gingerols (42.0, 5.3, and 4.8 nmol/L, respectively) were reached 30-60 min after ginger tea intake. Incubation of activated human T lymphocytes with gingerols increased the intracellular Ca(2+) concentration as well as the IFN-γ secretion by about 20-30%. This gingerol-induced increase of IFN-γ secretion could be blocked by the specific TRPV1 antagonist SB-366791. The results of the present study point to an interaction of gingerols with TRPV1 in activated T lymphocytes leading to an augmentation of IFN-γ secretion.

Protective effects of the standardized extract of Zingiber officinale on myocardium against isoproterenol-induced biochemical and histopathological alterations in rats

CONTEXT

Ginger [Zingiber officinale Roscoe. (Zingiberaceae)] has been universally used as a spice as well as for its health benefits.

OBJECTIVE

The present study evaluates the protective effect of the standardized extract of ginger against isoproterenol (ISO)-induced myocardial infarction (MI) in rats.

MATERIALS AND METHODS

Wistar rats were pretreated orally with three doses of standardized ginger extract (100, 200, and 400 mg/kg of body weight) or propranolol (5 mg/mL) for 28 d prior to ISO (85 mg/kg) induced MI in two doses on days 29 and 30. The rats were sacrificed 48 h after the first induction; serum and hearts were collected for biochemical and histopathological analysis.

RESULTS

Gingerols and shogaols were identified and quantitatively analyzed in the extracts using validated reversed phase HPLC methods. Pretreatment with ginger extract at 400 mg/kg showed a significant decrease (p < 0.05) in all the cardiac enzyme activities, i.e., cardiac troponin I (cTnI) (0.57 ng/mL), creatine kinase MB isoenzyme (CK-MB) (10.34 pg/mL), lactate dehydrogenase (LDH) (115.22 U/L), alanine transaminase (ALT) (15.79 U/L), and aspartate transaminase (AST) (46.72 U/L) when compared with ISO-control rats. There were significant rises (p < 0.05) in the activity of glutathione peroxide (GPx) (53.16 U/L), catalase (CAT) (210.41 U/L), and superoxide dismutase (SOD) (280.89 U/mL) of the pretreated rats when compared with the ISO-control. Histopathological examination showed an improvement in membrane cell integrity in pretreated rats compared with untreated rats.

CONCLUSION

The ethanol extract of ginger exhibited cardioprotective potential in treating myocardial injury following ISO administration.

Regioselective glucuronidation of gingerols by human liver microsomes and expressed UDP-glucuronosyltransferase enzymes: reaction kinetics and activity correlation analyses for UGT1A9 and UGT2B7

OBJECTIVES

To determine the reaction kinetics for regioselective glucuronidation of gingerols (i.e. 6-, 8- and 10-gingerol) by human liver microsomes and expressed UDP-glucuronosyltransferase (UGT) enzymes, and to identify the main UGT enzymes involved in regioselective glucuronidation of gingerols.

METHODS

The rates of glucuronidation were determined by incubating the gingerols with uridine diphosphoglucuronic acid-supplemented microsomes. Kinetic parameters were derived by fitting an appropriate model to the data. Activity correlation analyses were performed to identify the main UGT enzymes contributing to hepatic metabolism of gingerols.

KEY FINDINGS

Glucuronidation at the 4'-OH group was much more favoured than that at 5-OH. The degree of position preference was compound-dependent; the catalytic efficiency ratios of 4'-O- to 5-O-glucuronidation were 9.1, 19.7 and 2.9 for 6-, 8- and 10-gingerol, respectively. UGT1A8 (an intestinal enzyme), UGT1A9 and UGT2B7 were the enzymes showing the highest activity towards gingerols. Formation of 5-O-glucuronide was mainly catalysed by UGT1A9. UGT2B7 was the only enzyme that generated glucuronides at both 4'-OH and 5-OH sites, although a strong position preference was observed with 4'-OH (≥80.2%). Further, activity correlation analyses indicated that UGT2B7 and UGT1A9 were primarily responsible for 4'-O-glucuronidation and 5-O-glucuronidation of gingerols in the liver, respectively.

CONCLUSIONS

Gingerols were metabolized by multiple hepatic and gastrointestinal UGT enzymes. Also, UGT1A9 and 2B7 were the main contributors to regioselective glucuronidation of gingerols in the liver.

Anti-inflammatory activity of grains of paradise (Aframomum melegueta Schum) extract

The ethanolic extract of grains of paradise (Aframomum melegueta Schum, Zingiberaceae) has been evaluated for inhibitory activity on cyclooxygenase-2 (COX-2) enzyme, in vivo for the anti-inflammatory activity and expression of several pro-inflammatory genes. Bioactivity-guided fractionation showed that the most active COX-2 inhibitory compound in the extract was [6]-paradol. [6]-Shogaol, another compound from the extract, was the most active inhibitory compound in pro-inflammatory gene expression assays. In a rat paw edema model, the whole extract reduced inflammation by 49% at 1000 mg/kg. Major gingerols from the extract [6]-paradol, [6]-gingerol, and [6]-shogaol reduced inflammation by 20, 25 and 38%. respectively when administered individually at a dose of 150 mg/kg. [6]-Shogaol efficacy was at the level of aspirin, used as a positive control. Grains of paradise extract has demonstrated an anti-inflammatory activity, which is in part due to the inhibition of COX-2 enzyme activity and expression of pro-inflammatory genes.

Quantitative analysis of ginger components in commercial products using liquid chromatography with electrochemical array detection

For the first time, a sensitive reversed-phase HPLC electrochemical array method has been developed for the quantitative analysis of 8 major ginger components ([6]-, [8]-, and [10]-gingerol, [6]-, [8]-, and [10]-shogaol, [6]-paradol, and [1]-dehydrogingerdione) in 11 ginger-containing commercial products. This method was valid with unrivaled sensitivity as low as 7.3-20.2 pg of limit of detection and a range of 14.5-40.4 pg for the limit of quantification. The levels of 8 ginger components in 11 different commercial products were quantified by use of this method. The results found that both levels and ratios among the 8 compounds vary greatly in commercial products.

Quantitation of 6-, 8- and 10-Gingerols and 6-Shogaol in Human Plasma by High-Performance Liquid Chromatography with Electrochemical Detection

Zingiber officinale is one of the most commonly used spices. We developed a method to determine the main pungent ginger constituents, 6-, 8- and 10-gingerols and 6-shogaol in human plasma. Quantitation was achieved using a reversed-phase C(18) column using high-performance liquid chromatography with electrochemical detection. The assay was linear from 0.1 to 5.0 μg/mL. The within-day coefficients of variation for the assay at 5.0 μg/mL were ≤ 5% for all analytes. The recovery of all four analytes was ≥99% for at 5.0 μg/mL. The lower limit of quantitation was 0.1 μg/mL except for 10-gingerol which was 0.25 μg/mL. Currently, there is no analytical method for detecting pungent ginger constituents in human plasma. This HPLC method allows for the detection of all four of ginger's pungent constituents simultaneously in a relatively short run time of 25 minutes. This method should be useful for determining plasma levels of 6-, 8-, 10-gingerol and 6-shogaol in phase I clinical trials.

Toxicological evaluation of grains of paradise (Aframomum melegueta) [Roscoe] K. Schum

ETHNOPHARMACOLOGICAL RELEVANCE

Grains of Paradise (Aframomum melegueta [Roscoe] K. Schum.) seeds are used in West Africa as a remedy for variety of ailments such as stomach ache, snakebite, diarrhea and they have reported anti-inflammatory properties. Additionally, the seeds contain gingerols and related compounds that may be useful against cardiovascular disease, diabetes, and inflammation.

AIM OF STUDY

A 28-day sub-chronic toxicity study in male and female Sprague-Dawley rats was conducted to evaluate the safety of a Grains of Paradise extract.

MATERIALS AND METHODS

An ethanolic extract of the seeds was evaluated for toxicological effect on rats.

RESULTS

A dose-related increase in absolute and relative liver weights was observed in males and females dosed with 450 and 1500 mg/kg. There was a corresponding increase in alkaline phosphatase with no signs of steatosis or cirrhosis. At the same doses, there was a significant decrease in blood glucose in male rats.

CONCLUSIONS

This study shows that Grains of Paradise extract may be useful as a treatment for diabetes, however liver toxicity should be considered.

Ginger (Zingiber officinale Roscoe) and the gingerols inhibit the growth of Cag A+ strains of Helicobacter pylori

BACKGROUND

Ginger root (Zingiber officinale) has been used traditionally for the treatment of gastrointestinal ailments such as motion sickness, dyspepsia and hyperemesis gravidarum, and is also reported to have chemopreventative activity in animal models. The gingerols are a group of structurally related polyphenolic compounds isolated from ginger and known to be the active constituents. Since Helicobacter pylori (HP) is the primary etiological agent associated with dyspepsia, peptic ulcer disease and the development of gastric and colon cancer, the anti-HP effects of ginger and its constituents were tested in vitro.

MATERIALS AND METHODS

A methanol extract of the dried powdered ginger rhizome, fractions of the extract and the isolated constituents, 6-,8-,10-gingerol and 6-shogoal, were tested against 19 strains of HP, including 5 CagA+ strains.

RESULTS

The methanol extract of ginger rhizome inhibited the growth of all 19 strains in vitro with a minimum inhibitory concentration range of 6.25-50 micrograms/ml. One fraction of the crude extract, containing the gingerols, was active and inhibited the growth of all HP strains with an MIC range of 0.78 to 12.5 micrograms/ml and with significant activity against the CagA+ strains.

CONCLUSION

These data demonstrate that ginger root extracts containing the gingerols inhibit the growth of H. pylori CagA+ strains in vitro and this activity may contribute to its chemopreventative effects.

Gingerols: a novel class of vanilloid receptor (VR1) agonists

1. Gingerols, the pungent constituents of ginger, were synthesized and assessed as agonists of the capsaicin-activated VR1 (vanilloid) receptor. 2. [6]-Gingerol and [8]-gingerol evoked capsaicin-like intracellular Ca(2+) transients and ion currents in cultured DRG neurones. These effects of gingerols were blocked by capsazepine, the VR1 receptor antagonist. 3. The potency of gingerols increased with increasing size of the side chain and with the overall hydrophobicity in the series. 4. We conclude that gingerols represent a novel class of naturally occurring VR1 receptor agonists that may contribute to the medicinal properties of ginger, which have been known for centuries. The gingerol structure may be used as a template for the development of drugs acting as moderately potent activators of the VR1 receptor.