Determination of 6-gingerol in ginger (Zingiber officinale) using high-performance thin-layer chromatography

A sensitive and accurate High-Performance TLC (HPTLC) method has been developed to determine the quantity of 6-gingerol in rhizomes of Zingiber officinale (family: Zingiberaceae), commonly known as ginger. Methanol extracts of rhizomes from three different sources were used for HPTLC, n-hexane, and diethyl ether (40:60 v/v) as the mobile phase. The Rf of 6-gingerol was found to be 0.40. The calibration plot was linear in the range of 250-1200 ng of 6-gingerol and the correlation coefficient of 0.9997 was indicative of good linear dependence of peak area on concentration. The mean quantity of 6-gingerol was found to be 60.44+/-2.53 mg/g of ginger extract. The method permits reliable quantification of 6-gingerol and good resolution and separation of 6-gingerol from other constituents of ginger. To study the accuracy and precision of the method, recovery studies were performed by the method of standard addition. Recovery values from 99.79 to 99.84% showed the excellent reliability and reproducibility of the method. The proposed HPTLC method for quantitative monitoring of 6-gingerol in ginger can be used for routine quality testing of ginger extracts.     

Pharmacokinetics of [6]-gingerol after intravenous administration in rats with acute renal or hepatic failure.

The pharmacokinetics of [6]-gingerol were investigated in rats with acute renal failure induced by bilateral nephrectomy, or those with acute hepatic failure induced by a single oral administration of carbon tetrachloride (CCl4), to clarify the contribution of the kidney and liver to the elimination process of [6]-gingerol. After bolus intravenous administration, a plasma concentration-time curve of [6]-gingerol was illustrated by a two-compartment open model. There was no significant difference in either the plasma concentration-time curve or any pharmacokinetic parameters between the control and nephrectomized rats. It is suggested, therefore, that renal excretion does not contribute at all to the disappearance of [6]-gingerol from plasma in rats. In contrast, hepatic intoxication with CCl4 elevated the plasma concentration of [6]-gingerol at the terminal phase. Its elimination half-life increased significantly, from 8.5 to 11.0 min, in CCl4-intoxicated rats. The extent of [6]-gingerol bound to serum protein was more than 90% and was affected very slightly by the CCl4-intoxication. These aspects indicate that [6]-gingerol is eliminated partly by the liver.     

Immunosuppressive activity of 8-gingerol on immune responses in mice

8-gingerol is one of the principal components of ginger, which is widely used in China and elsewhere as a food, spice and herb. It shows immunosuppressive activity on the immune responses to ovalbumin (OVA) in mice. In the present study, we found that 8-gingerol suppressed lipopolysaccharide (LPS) and concanavalin A (ConA)-stimulated splenocyte proliferation in vitro. In vivo, 8-gingerol not only signi?cantly suppressed Con A-, LPS- and OVA-induced splenocyte proliferation (P < 0.05) but also decreased the percentage of CD19+ B cells and CD3+ T cell (P < 0.05) at high doses (50, 100 mg/kg). Moreover, OVA-speci?c IgG, IgG1 and IgG2b levels in OVA-immunized mice were reduced by 8-gingerol at doses of 50, 100 mg/kg. These results suggest that 8-gingerol could suppress humoral and cellular immune responses in mice. The mechanism might be related to direct inhibition of sensitized T and B lymphocytes.     

Screening for the extracorporeal coagulation activity quality markers (Q-markers) of dried and stir fried ginger

Ginger is a common condiment that is widely used as Chinese medicine in China and Southeast Asia. Dried ginger and stir fried ginger are two common processed products of ginger, with distinct clinical uses. The aim of this study was to identify the chemical components (quality markers, Q-mark) responsible for the differences in in vitro hemostatic activity between dried and stir fried ginger and to provide a basis for the selection between the two types of ginger in clinical application. In this study, methanolic extracts of dried and stir fried ginger were characterized using UPLC-Q/TOF-MS and then evaluated for in vitro coagulation activity. Spectral effect correlation analysis was used to identify quality markers, while molecular docking simulation was used to evaluate the binding energy between potential active compounds and target proteins. A total of 49 chemical constituents of the ginger extracts were identified using UPLC-Q/TOF-MS, 27 of which were significantly different between the two extracts. A fingerprint of 18 batches of dried and stir fried ginger established that zingiberone, 6-gingerol, 8-gingerol, 6-shogaol, 10-gingerol, 8-shogaol, and 10-shogaol were common constituents of the two extracts. Results of coagulation assays revealed that dried ginger had anti-coagulation effects, while stir fried ginger had hemostatic effect. Zingiberone, 6-shogaol and 10-shogaol were identified as the active components responsible for the hemostatic effect of Stir fried ginger through multivariate statistical analysis. In addition, molecular docking simulations suggested that these three components bound to Src proteins on platelets. Consequently, 6-gingerol, zingiberone, 6-shogaol and 10-shogaol were selected as quality markers to distinguish between dried and stir fried ginger. These results provide scientific evidence for the establishment of a quality evaluation system for the integrity and specificity of dried and stir fried ginger.     

Determination of Gingerols in Ginger by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A rapid and sensitive ultra-high performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of 6-, 8-, and 10-gingerol in the rhizomes of Zingiber officinale Rosc. The chromatographic separation was achieved isocratically on a C₁₈ (2.1 mm × 100 mm; 1.7 µm) column using acetonitrile:water (90:10 v/v) at a flow rate of 0.25 mL/min. Mass spectrometric transitions for 6-gingerol, 8-gingerol, and 10-gingerol occurred at m/z 277.2467/177.1470, 305.3196/177.1617, and 333.3614/177.1666, respectively. The analysis time was 3.0 min and the elution of 6-, 8-, and 10- gingerol occurred at 1.27, 1.51, and 1.80 min. The linear dynamic range was established over the concentration range of 2 and 1000 ng/mL for the analytes. The limits of detection and quantitation for 6-gingerol, 8-gingerol, and 10-gingerol were 0.921, 0.856, and 1.069 ng/mL, and 2.951, 2.727, and 3.013 ng/mL, respectively. The relative standard deviation and accuracy were found to be satisfactory. The results showed significant variation (0.176%–0.290% w/w) in gingerols among twelve accessions and that the Patna and Lucknow varieties contained the highest concentrations and were concluded to be superior. These results may be used to devise strategies for cultivating this plant for large scale production.     

Synthesis of fluorinated 2,3-dihydropyran-4-ones by cyclocondensation of 1,3-dicarbonyl dianions with aldehydes

The reaction of the dianion of 1,1,1-trifluoro-pentane-2,4-dione with aldehydes and subsequent addition of hydrochloric acid afforded 2,3-dihydro-6-trifluoromethyl-pyran-4-ones. The reaction of the dianion of acetylacetone with fluorinated benzaldehydes gave the corresponding fluorinated 2-aryl-2,3-dihydro-6-methyl-pyran-4-ones. All reactions proceeded in very good yield and with very good regioselectivity.     

Anti-Platelet Aggregation and Vasorelaxing Effects of the Constituents of the Rhizomes of<em> Zingiber officinale</em>

In the present study, the chemical investigation of the bioactive fractions of the rhizomes of Zingiber officinale has resulted in the identification of twenty-nine compounds including one new compound, O-methyldehydrogingerol (1). Some of the isolates were subjected into the evaluation of their antiplatelet aggregation and vasorelaxing bioactivities. Among the tested compounds, [6]-gingerol (13) and [6]-shogaol (17) exhibited potent anti-platelet aggregation bioactivity. In addition, [10]-gingerol (15) inhibited the Ca²⁺-dependent contractions in high K⁺ medium. According to the results in the present research, the bioactivity of ginger could be related to the anti-platelet aggregation and vasorelaxing mechanism.     

Neutral and anionic guests and their effect on the formation of pseudorotaxanes by using a flexible tetracationic imidazolium macrocycle

The ability to control and direct molecular assembly has important implications in the design of environmentally responsive materials. Reported here is the use of competitive neutral- and anionic-guest recognition to control the formation, disruption, replacement-based construction and higher-order assembly properties of pseudorotaxane structures involving a large, cationic tetraimidazolium receptor. In particular, we showed that the chloride anion (as the tetrabutylammonium (TBA(+)) salt) serves to replace directly the 2,6-naphthalene dicarboxylate dianion from the preformed complex, involving this dianion. In contrast, the addition of the nitrate anion (as the TBA(+) salt) serves to effect displacement of a pre-bound 2,6-naphthalene dicarboxylate dianion in a stepwise manner allowing for stabilization of a so-called "outside"-binding mode under appropriate conditions. We have also found that by using biphenyl-3,4,3',4'-tetraamine as the guest, a 1D-donor-acceptor-donor coordination polymer can be stabilized, whereas the addition of 6-amino-naphthalene-2-sulfonate anion to the pre-formed complex between the tetraimidazolium receptor and the 2,6-naphthalene dicarboxylate dianion produces a new pseudorotaxane complex. This guest-based competition and subsequent molecular translocation is supported by solution-state NMR spectroscopic studies as well as solid-state single-crystal X-ray structural analyses. The results described herein provide initial evidence that guest competition can be used to control molecular "switching" and substrate binding within an appropriately designed anion receptor.     

The Crotyl Alcohol Dianion: Addition Reactions

Conditions are developed for the generation and subsequent addition of crotyl alcohol dianion.     

Pharmacokinetics of [6]-gingerol after intravenous administration in rats

A high-performance liquid chromatographic method to determine [6]-gingerol, a pungent constituent of ginger, in rat plasma was developed and a pharmacokinetic study was performed in rats. Quantitative analysis with high reproducibility was achieved for [6]-gingerol over the concentration range of 0.2-40 micrograms/ml. After bolus intravenous administration at a dose of 3 mg/kg, the plasma concentration-time curve was described by a two-compartment open model. [6]-Gingerol was rapidly cleared from plasma with a terminal half-life of 7.23 min and a total body clearance of 16.8 ml/min/kg. Serum protein binding of [6]-gingerol was 92.4%.     

Reactivity of a novel ambident dianion formed by double deprotonation of β-thiosubstituted dithiopropanoates : A lithio-acrylate equivalent.

A novel lithium allyl dianion has been generated by double deprotonation of β-alkyl (aryl) thio-dithioester. Reactions of this dianion with alkyl iodide, trimethylsilyl chloride and epoxyde occur at the γ-site. The regiochemistry of its addition to carbonyl compounds depends on the carbonyl compounds, e.g., for aldehydes ketones, α -and γ-regioselectivity respectively, were observed. The reactivity with cyclopentenone was also examined.γ-Selectivity with alkyl halides and epoxydes; γ and α-prefered selectively with respectively ketones and aldehydes.     

A Mixed-Anion System Consisting of a Germyl Anion and Anions Delocalized on Conjugated Carbon Ring Skeletons

A trianion consisting of one germyl anion and two anions delocalized on conjugated carbon ring skeletons was synthesized by trimerization of the germanium analogue of the anthryl anion, which exhibits high germylene character. In addition, the generation of the putative intermediate of this reaction, the radical anion of 9-germaanthracene, was confirmed by the formation of the corresponding dimeric dianion. The isolated trianion and dianion were characterized by X-ray crystallographic analysis together with NMR spectroscopy and theoretical calculations.     

Interaction of alkali metals with unsaturated heterocyclic compounds. The reductive metalation of 1,4-diphenylphthalazine

1,4-Diphenylphthalazine ( 1 ) was reduced in tetrahydrofuran by sodium metal to a monomeric dianion 2 . Chemical reactions of this new dianion were examined with various reagents. Generally, the protonation, acylation and alkylation products were 1,2-dihydrophthalazine derivatives. An annulation of the phthalazine ring system was accomplished by treating the dianion with 1,3-dichloropropane or 1,4-dichlorobutane. With 1,2-dichloroethane however, only 1,4-diphenylnaphthalene was detected.     

The alkali metal reduction of pyrene structural and preparative aspects

Reduction of pyrene with alkali metals yields the corresponding dianion salts. The solvent, counterion and temperature must be carefully selected since side reactions such as protonation (e.g. in liquid ammonia) or cleavage of the etheral solvent occur readily. Moreover, the spectroscopic characterization of the dianion is complicated by rapid electron transfer processes. There is no experimental evidence for distorted dianion structures or for further reduction of pyrene toward a tetraanion. Knowledge of the ionic π-structures is essential for an understanding of reductive alkylation processes.     

Preparation of the monomers of gingerols and 6-shogaol by flash high speed counter-current chromatography

The flash high speed counter-current chromatographic (FHSCCC) separation of gingerols and 6-shogaol was performed on a HSCCC instrument equipped with a 1200-ml column (5 mm tubing i.d.) at a flow rate of 25 ml/min. The performance met the FHSCCC feature that the flow rate of mobile phase (ml) is equal to or greater than the square of the diameter of the column tubing (mm). The separation employed the upper phase of stationary phase of the n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) as the stationary phase. A stepwise elution was performed by eluting with the lower phase of n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) for first 90 min and the lower phase of the n-hexane-ethyl acetate-methanol-water (3:2:6:5, v/v) for the second 90 min. In each separation 5 g of the ethyl acetate extract of rhizomes of ginger was loaded, yielding 1.96 g of 6-gingerol (98.3%), 0.33 g of 8-gingerol (97.8%), 0.64 g of 6-shogaol (98.8%) and 0.57 g of 10-gingerol (98.2%). The separation can be expected to scale up to industrial separation.     

Titanium-induced conjugated addition of the fluorenone dianion to α, β-enones.

Cross-coupling of fluorenone and enones with TiCL₄Mg led to γ-ketol derivatives resulting of a conjugate addition of the fluorenone dianion to enones.     

Reduction of diesters of 1,2-diols. Regioselective C-O bond cleavage of the anionic forms

The electrochemical reduction of benzoate diesters of glycols has been studied in acetonitrile and N,N-dimethylformamide as solvents. The reductions occur in two closely spaced one-electron steps, and it was found that the dianion diradicals decompose by one of two routes, depending on the substituents on the ethylene moiety: cleavage of two benzoates to produce alkene or formation of benzil by way of a postulated cyclic intermediate to produce also the dianion of the diol. These correspond to cleavage of the R-OC(O)Ar bonds and the RO-C(O)Ar bonds, respectively. When the radical formed by the former cleavage is a primary or secondary radical, the reaction is too slow to compete with the latter reaction that produces benzil. However, when that radical is either tertiary or benzylic, the former cleavage reaction is fast and no benzil is detected. The dianions of p-cyano- and p-nitrobenzoate esters are rather stable on the voltammetric time scale. However, the addition of lithium ions results in detectable formation of 4,4'-dicyanobenzil from four different p-cyanobenzoate diesters.     

Small gas-phase dianions produced by sputtering and gas flooding

We have extended our previous experiment [Schauer et al., Phys. Rev. Lett. 65, 625 (1990)] where we had produced small gas-phase dianion clusters of C(n) (2-)(n > or =7) by means of sputtering a graphite surface by Cs(+) ion bombardment. Our detection sensitivity for small C(n) (2-) could now be increased by a factor of about 50 for odd n. Nevertheless, a search for the elusive pentamer dianion of C(5) (2-) was not successful. As an upper limit, the sputtered flux of C(5) (2-) must be at least a factor of 5000 lower than that of C(7) (2-), provided that the lifetime of C(5) (2-) is sufficiently long to allow its detection by mass spectrometry. When oxygen gas (flooding with either O(2) or with N(2)O) was supplied to the Cs(+)-bombarded graphite surface, small dianions of OC(n) (2-)(5< or =n < or =14) and O(2)C(7) (2-) were observed in addition to C(n) (2-)(n > or =7). Similarly, Cs(+) sputtering of graphite with simultaneous SF(6) gas flooding produced SC(n) (2-)(6< or =n< or =18). Mixed nitrogen-carbon or fluorine-carbon dianion clusters could not be observed by these means. Attempts to detect mixed metal-fluoride dianions for SF(6) gas flooding of various Cs(+)-bombarded metal surfaces were successful for the case of Zr, where metastable ZrF(6) (2-) was observed. Cs(+) bombardment of a silicon carbide (SiC) wafer produced SiC(n) (2-) (n=6,8,10). When oxygen gas was supplied to the Cs(+)-bombarded SiC surface, small dianions of SiOC(n) (2-) (n=4,6,8) and of SiO(2)C(n) (2-) (n=4,6) as well as a heavier unidentified dianion (at mz=98.5) were observed. For toluene (C(7)H(8)) vapor flooding of a Cs(+)-bombarded graphite surface, several hydrocarbon dianion clusters of C(n)H(m) (2-)(n> or =7) were produced in addition to C(n) (2-)(n> or =7), while smaller C(n)H(m) (2-) with n< or =6 could not be observed. BeC(n) (2-) (n=4,6,8,10), Be(2)C(6) (2-), as well as BeC(8)H(m) (2-) (with m=2 and/or m=1) were observed for toluene vapor flooding of a Cs(+)-bombarded beryllium metal foil. The metastable pentamer (9)Be(12)C(4) (2-) at mz=28.5 was the smallest and lightest dianion molecule that we could detect. The small dianion clusters of SC(n) (2-), OC(n) (2-), BeC(n) (2-), and SiO(m)C(n) (2-) (m=0,1,2) have different abundance patterns. A resemblance exists between the abundance patterns of BeC(n) (2-) and SiC(n) (2-), even though calculated molecular structures of BeC(6) (2-) and SiC(6) (2-) are different. The abundance pattern of SC(n) (2-) is fairly similar to that of C(n) (2-).     

Rapid and Accurate Analytical Method for the Determination of Gingerols in Three Medicinal Gingers (Zingiber officinale Roscoe) by High Performance Liquid Chromatography

Abstract

A rapid, simple, sensitive, and accurate high performance liquid chromatographic (HPLC) method has been developed and validated for the simultaneous determination of 6-gingerol, 8-gingerol, and 10-gingerol in three medicinal gingers. The chromatographic separation of three gingerols was achieved within 4 min on a sub-2 µm particles column. Gradient elution was performed using acetonitrile-water as the mobile phase at a flow rate of 1.0 mL/min. The injection volume was 2 µL, and the detection wavelength was set at 280 nm. Validation studies revealed that the method was reliable and reproducible for the simultaneous quantitation of the three gingerols in three medicinal gingers.