Comparative antioxidant and anti-inflammatory effects of [6]-gingerol, [8]-gingerol, [10]-gingerol and [6]-shogaol

Ethnopharmacological relevance

Zingiber officinale Rosc. (Zingiberaceae) has been traditionally used in Ayurvedic, Chinese and Tibb-Unani herbal medicines for the treatment of various illnesses that involve inflammation and which are caused by oxidative stress. Although gingerols and shogaols are the major bioactive compounds present in Zingiber officinale, their molecular mechanisms of actions and the relationship between their structural features and the activity have not been well studied.

Aim of the study

The aim of the present study was to examine and compare the antioxidant and anti-inflammatory activities of gingerols and their natural analogues to determine their structure–activity relationship and molecular mechanisms.

Materials and methods

The in vitro activities of the compounds [6]-gingerol, [8]-gingerol, [10]-gingerol and [6]-shogaol were evaluated for scavenging of 1,1-diphenyl-2-picyrlhydrazyl (DPPH), superoxide and hydroxyl radicals, inhibition of N-formyl-methionyl-leucyl-phenylalanine (f-MLP) induced reactive oxygen species (ROS) production in human polymorphonuclear neutrophils (PMN), inhibition of lipopolysaccharide induced nitrite and prostaglandin E₂ production in RAW 264.7 cells.

Results

In the antioxidant activity assay, [6]-gingerol, [8]-gingerol, [10]-gingerol and [6]-shogaol exhibited substantial scavenging activities with IC₅₀ values of 26.3, 19.47, 10.47 and 8.05 μM against DPPH radical, IC₅₀ values of 4.05, 2.5, 1.68 and 0.85 μM against superoxide radical and IC₅₀ values of 4.62, 1.97, 1.35 and 0.72 μM against hydroxyl radical, respectively. The free radical scavenging activity of these compounds also enhanced with increasing concentration (P < 0.05). On the other hand, all the compounds at a concentration of 6 μM have significantly inhibited (P < 0.05) f-MLP-stimulated oxidative burst in PMN. In addition, production of inflammatory mediators (NO and PGE₂) has been inhibited significantly (P < 0.05) and dose-dependently.

Conclusions

6-Shogaol has exhibited the most potent antioxidant and anti-inflammatory properties which can be attributed to the presence of α,β-unsaturated ketone moiety. The carbon chain length has also played a significant role in making 10-gingerol as the most potent among all the gingerols. This study justifies the use of dry ginger in traditional systems of medicine.     

Analgesic and anti-inflammatory activities of [6]-gingerol

In the present study, the analgesic and anti-inflammatory effects of [6]-gingerol, which is the pungent constituent of ginger, were performed. Intraperitoneal administration of [6]-gingerol (25 mg/kg-50 mg/kg) produced an inhibition of acetic acid-induced writhing response and formalin-induced licking time in the late phase. [6]-Gingerol (50 mg/kg-100 mg/kg) also produced an inhibition of paw edema induced by carrageenin. These results suggested that [6]-gingerol possessed analgesic and anti-inflammatory activities.     

6]-gingerol induces Ca2+ mobilization in Madin-Darby canine kidney cells

[6]-gingerol, a major phenolic compound derived from ginger (Zingiber officinale), is a potential chemopreventive compound that can induce stress in cancer cells and cause apoptotic cell death. This study examines the early signaling effects of [6]-gingerol on renal cells. It was found that [6]-gingerol caused a slow and sustained rise of [Ca2+]i in a concentration-dependent manner. [6]-gingerol also induced a [Ca2+]i rise when extracellular Ca2+ was removed, but the magnitude was reduced by 80%. Depletion of intracellular Ca2+ stores with CCCP, a mitochondrial uncoupler, did not affect the action of [6]-gingerol. In a Ca2+-free medium, the [6]-gingerol-induced [Ca2+]i rise was partially abolished by depleting stored Ca2+ with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). The elevation of [6]-gingerol-caused [Ca2+]i in a Ca2+-containing medium was not affected by modulation of protein kinase C activity. The [6]-gingerol-induced Ca2+ influx was blocked by nicardipine. U73122, an inhibitor of phospholipase C, abolished ATP (but not [6]-gingerol)-induced [Ca2+]i rise. These findings suggest that [6]-gingerol induces a significant rise in [Ca2+]i in MDCK renal tubular cells by stimulating both extracellular Ca2+ influx and thapsigargin-sensitive intracellular Ca2+ release via as yet unidentified mechanisms.     

HPLC-UV法测定大鼠血中[6]-姜酚的浓度

目的建立测定大鼠血浆中[6]-姜酚浓度的HPLC-UV法,为进一步研究[6]-姜酚的药代动力学提供可靠的方法。方法大鼠血浆样品以液-液萃取法提取后,采用HPLC-UV测定大鼠血浆中[6]-姜酚的浓度。HPLC条件:Hypersil C18柱(250mm×4.6mm,5μm),乙腈-水(45:55)为流动相,进样量:20μL,流速:1.0mL/min,紫外检测波长:280nm。结果[6]-姜酚线性范围为0.25～5.0μg/mL,最低检测限为0.1μg/mL,日内精密度RSD5.5%,日间精密度RSD6.8%。结论该测定方法具有灵敏、专一和快速的优点,可用于测定大鼠灌胃给药后[6]-姜酚的血浆浓度。     

Cholagogic effect of ginger and its active constituents

The effect of bile secretion in rats was examined in order to clarify the stomachic action of ginger and also to investigate its active constituents. The results showed that mainly the acetone extracts of ginger, which contain essential oils and pungent principles, caused an increase in the bile secretion. Further analyses for the active constituents of the acetone extracts through column chromatography indicated that [6]-gingerol and [10]-gingerol, which are the pungent principles, are mainly responsible for the cholagogic effect of ginger.     

花椒属植物对口腔致病菌的抗菌活性

目的：比较6种花椒属(Zanthoxylm)植物乙醇提取物对口腔致病菌的抗菌活性，从中寻找抗菌的活性物质。方法：用于抗菌活性实验的口腔致病菌是变形链球菌(Streptococcus mutans ATCC 25175)，放线菌(Aainomyces naeslundii ATCC 12104)和嗜血放线伴生杆菌(Actinobacillus actinomycetemicomtans ATCC 43717)。抗菌实验为琼脂扩散法(agar diffusion assays)和最低抑菌浓度法(MIC)。结果：拟蚬壳花椒(Z．lactura)的根对这些口腔致病菌表现出最强的抗菌活性，其次是两面针(Z．nitidum)和异叶花椒(Z．dimorphyllum)的根。进而对异叶花椒(Z．dimorphyllum)的根进行化学成分研究，分离到4个已知化合物，其中化合物Canthin-6-one对这三种口腔致病菌均有很强的抗菌能力，最低抑菌浓度(MIC)在15．6和62．5μg／mL之间。结论：Canthin-6-one可能是异叶花椒抗菌活性的物质基础。     

Bioassay-guided isolation and identification of antifungal compounds from ginger

A bioassay-guided isolation of antifungal compounds from an African land race of ginger, Zingiber officinale Roscoe, led to the identification of [6], [8] and [10]-gingerols and [6]-gingerdiol as the main antifungal principles. The compounds were active against 13 human pathogens at concentrations of <1 mg/mL. The gingerol content of the African land race was at least 3 x higher than that of typical commercial cultivars of ginger. Therefore, ginger extracts standardized on the basis of the identified compounds, could be considered as antifungal agents for practical therapy.     

Antibacterial activity of diospyrin, isodiospyrin and bisisodiospyrin from the root of Diospyros piscatoria (Gurke) (Ebenaceae)

Two dimeric naphthoquinones, diospyrin and isodiospyrin, isolated from the root of Diospyros piscatoria (Gurke), a common ingredient in several folk medicines, have been shown to have a broad spectrum of antibacterial activity. The minimum inhibitory concentrations (MICs) of diospyrin against Streptococcus pyogenes ATCC 12344 and Streptococcus pneumoniae ATCC 33400 ranged from 1.56 to 50 microg/mL. While those against Salmonella choleraesuis serotype typhi (S. typhi), ATCC 6539 and Mycobacterium chelonae ATCC 19977 were between 25 and 100 microg/mL. Isodiospyrin was more active than its racemic isomer diospyrin. The MICs against Gram-positive bacteria ranged from 0.78 to 50 microg/mL. While those against Pseudomonas aeruginosa ATCC 15443 and S. typhi ranged from 50 to 100 microg/mL. The MIC for M. chelonae was between 6.25 and 25 microg/mL. MICs were found to increase with the concentration of cells used for the inoculum. The MICs for Bacillus subtilis ATCC 6633 increased up to the highest concentration of cells tested. The same phenomenon was observed on M. chelonae, but with better effect in the latter. The kinetics of bacteria studies against both B. subtilis and M. chelonae increases with increasing concentration of isodiospyrin tested. Two tetrameric forms of plumbagin were isolated. The naphthoquinone bisisodiospyrin, gave MIC values between 300 and 400 micro g/mL. The second, as yet unidentified tetramer, was not active at 500 micro g/mL.     

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis

The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis.     

高效液相色谱法同时测定姜及其不同炮制品中5种姜辣素的含量

 目的 建立测定姜及其炮制品中的姜酮、6-姜酚、8-姜酚、6-姜烯酚、10-姜酚含量的方法,并对生姜、干姜、炮姜、姜炭中的5种姜辣素化学成分进行定量分析比较,探讨5种化学成分在姜的炮制过程中的变化规律。方法 用Kromasil -C₁₈柱（4.6 mm×250 mm,5 μm）,流动相为乙腈（B）-0.1%醋酸水溶液（A）,梯度洗脱（0~10 min,B：40%;10~40 min,B：40%→90%;40~45 min,B：90%→100%;45~50 min,B：100%→40%）,流速1.0 mL·min^-1,检测波长275 nm,柱温30 ℃,进样量10 μL。结果 5个成分的线性范围分别为姜酮：0.625～20 μg·mL^-1(r=0.999 1)、6-姜酚：6.25～200 μg·mL^-1(r=0.999 7)、8-姜酚：1.25～40 μg·mL^-1(r=0.999 9)、6-姜烯酚：1.25～40 μg·mL^-1(r=0.999 1)、10-姜酚：1.875～60 μg·mL^-1(r=0.999 4);平均回收率(n=6)分别为101.5%,100.9%,104.7%,102.1%,105.5%;RSD分别为1.26%,1.60%,3.35%,2.98%,3.05%;从生姜到干姜、炮姜、姜炭的炮制过程中6-姜酚,8-姜酚,10-姜酚相对含量逐渐降低,6-姜烯酚的相对含量逐渐增高;姜酮在加工至炮姜时出现,且含量较少,在姜炭中含量有所增加。结论 本方法具有良好的重复性,能够准确的测定姜及其炮制品中5种成分的含量,为评价姜及其炮制品的质量提供了分析方法;生姜在炮制过程中,5种姜辣素类成分在质与量上均发生了变化。
     

Antifouling activity of meroditerpenoids from the marine brown alga Halidrys siliquosa

Nine tetraprenyltoluquinol-related metabolites (1-9) have been isolated from the organic extract of the temperate brown alga Halidrys siliquosa that exhibits antifouling properties. The planar structure of compounds 1-9 was elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of related metabolites. Antifouling and toxicity tests were conducted on these compounds: the most active (compounds 2, 6, and 9) inhibited both the growth of four strains of bacteria (MICs < 2.5 microg/mL) and settlement of cyprids of Balanus amphitrite (EC50 < 5 microg/mL), the latter at nontoxic concentrations (LC50 > 5 microg/mL).     

作炮制辅料用姜汁的HPLC指纹图谱比较

目的:对3种不同制法所得炮制辅料用姜汁进行RP-HPLC指纹图谱的比较研究。方法:Alltech C₁₈色谱柱(4.6 mm×250 mm,5μm),乙腈-水梯度洗脱,检测波长280 nm,柱温25℃,流速0.8 mL·min^-1。结果:相同品种不同批次姜汁间的化学成分差别小,榨汁与煮汁间的成分差异显著。3种制法所得姜汁及生姜、干姜中共有成分为色氨酸和6-姜辣素,其中煎煮的姜汁(生姜煎汁、干姜煎汁)中又有6-姜酚出现。结论:利用RP-HPLC指纹图谱分析法可较全面的反映不同制法的姜汁间的差异;生姜榨汁较全面的保留了生姜的指纹特征且各成分含量较高。     

Antibacterial activity of two canthin-6-one alkaloids from Allium neapolitanum

The emergence of multidrug-resistant strains of many human pathogens has led to an urgent need for the discovery and development of new antimicrobial agents. As part of an ongoing investigation into the antibacterial properties of the Alliaceae, the isolation of 1 (canthin-6-one), 2 (8-hydroxy-canthin-6-one) and 3 (5(zeta)-hydroxy-octadeca-6(E)-8(Z)-dienioc acid)) from A. neapolitanum, a perennial bulbous herb found in open pastures of the Mediterranean is reported. Compounds 1 and 2 were isolated by Sephadex LH-20 from fractions exhibiting a positive reaction with Dragendorff's reagent on TLC, compound 3 was isolated after HPLC purification of Sephadex fractions. Structures were elucidated by extensive 1D and 2D NMR experiments and are in accordance with published data, however, the 13C NMR data for compound 2 and the 1H and 13C NMR data for compound 3 are reported here for the first time. Canthin-6-one alkaloids are well-known constituents of the Simaroubaceae and Rutaceae, and display a wide range of biological activities. These metabolites are reported as constituents of the Alliaceae here for the first time, and displayed minimum inhibitory concentrations (MICs) in the range 8-32 microg/mL against a panel of fast-growing Mycobacterium species and 8-64 microg/mL against multidrug-resistant (MDR) and methicillin-resistant (MRSA) strains of Staphylococcus aureus. Compound 3 displayed antimycobacterial activity in the range of 16-32 microg/mL.     

Pharmacological evidence for an interaction between constituents (blend effect) of the Japanese-Sino medicine “Keishi-ka-zyutubu-tō” in neuromuscular blockade in diabetic mice

The pharmacological interaction between constituents of Keishi-ka-zyutubu-tō (composed of 7 crude drugs, namely peony, liquorice, jujube, cassia, ginger, Atractylodes lancea, and aconite), a medicine of Japanese-Sino origin, was investigated in in situ sciatic nerve-gastrocnemius muscle preparations using genetically dlabetic KK-CA^y mice. When administered intra-arterially, the drug caused a degree of inhibition of the diabetic neuromuscular junction 280 times greater than normal. The two constituents, peony-liquorice, were only 2.6 times more potent in diabetic muscles. When further combined with peony-liquorice, the potency ratio was increased 4.9 times for cassia, 5.9 times for ginger and 8.7 times for Atractylodes lancea. In combination with the representative compounds contained in the above crude drugs except for jujube, the potency ratio of paeoniflorin (PF) and glycyrrhizin (GLR) was increased 6.6 times for cinnamaldehyde, 6.1 times for [8]-gingerol and 14 times for β-eudesmol in diabetic muscles. Aconite potentiated the blocking effects of peony-liquorice to the same extent in diabetic muscles as in normal muscles. This tendency was also confirmed when mesaconitine was combined with PF-GLR. The single effect of β-eudesmol or [8]-gingerol was 5.2 times or 3.7 times more potent, respectively, on diabetic muscles than on normal muscles. Cinnamaldehyde or mesaconitine demonstrated the same degree of sensitivity in both diabetic and normal muscles. These results indicated that the preferentially more potent neuromuscular blocking effects of Keishi-ka-zyutubu-tō in diabetic muscles were mainly attributable to β-eudesmol, a major component of Atractylodes lancea.     

ent-rosane and labdane diterpenoids from Sagittaria sagittifolia and their antibacterial activity against three oral pathogens

Seven new ent-rosane diterpenoids, sagittines A-G (1-7), together with one new labdane diterpene, 13-epi-manoyl oxide-19-O-alpha-l-2',5'-diacetoxyarabinofuranoside (8), were isolated from the whole plant of Sagittaria sagittifolia. The structures and relative configurations of 1-8 were characterized using spectroscopic means, chemical methods, and X-ray crystallography. Compounds 1-4 exhibited antibacterial activity against the oral pathogens Streptococcus mutans ATCC 25175 and Actinomyces naeslundiis ATCC 12104, with MIC values between 62.5 and 125 microg/mL. Compound 5 was active against only A. naeslundiis ATCC 12104, with an MIC value of 62.5 microg/mL.     

干姜经不同炮制法对6-姜酚含量的影响

目的:研究干姜经不同的炮制方法对其主要化学成分6-姜酚含量的影响。方法:采用HPLC测定炒黄、炒炭(清炒、闷煅)、麸炒、砂炒等不同炮制工艺后干姜中6-姜酚含量的变化。结果:传统炮制中6-姜酚的含量从大到小依次为:炒黄>麸炒>干姜>砂炒>炒炭>闷煅。结论:炮制火候和条件是影响干姜中6-姜酚含量的主要因素,炒黄的温度条件相对最低,其6-姜酚含量最高为8.57 mg·g-1,麸炒温度条件比炒黄稍高一些,其6-姜酚含量为8.14 mg·g-1,说明一定受热程度有利于提高干姜中6-姜酚含量。     

Chemical Constituents in Essential Oils from Elsholtzia ciliata and Their Antimicrobial Activities

Objective To compare the chemical constituents in the essential oils from the leaves, flowers, and seeds of Elsholtzia ciliata and their antimicrobial activities. Methods The chemical constituents in essential oils were extracted by the hydro-distillation method and analyzed by GC-MS. The chemical constituents in essential oils were identified on the basis of comparison on their retention indices and MS spectrum with published data. Moreover, the antimicrobial activities of the chemical constituents in the oils against the growth of six bacteria strains and one pathogenic yeast strain were evaluated by using minimum inhibitory concentration and minimum bactericidal concentration methods. Results A total of 58 compounds were identified, while compounds 31, 35, and 36 were identified in the essential oils from the leaves, flowers, and seeds, respectively. Fifteen compounds were identified as shared constituents in the leaves, flowers, and seeds. The chemical constituents in the essential oils showed the inhibitory activities against the six bacteria strains and the yeast strain. Conclusion The major constituents are different in the essential oils of the leaves, flowers, and seeds. The major chemical constituents in the essential oils are monoterpenoids and sesquiterpenoids. And the chemical constituents in the essential oils obtained from the leaves show higher inhibitory activities especially against Bacillus subtillis CMCC63501 and Escherichia coli ATCC25922.     

Zingiber officinale (ginger) compounds have tetracycline‐resistance modifying effects against clinical extensively drug‐resistant Acinetobacter baumannii

Extensively drug‐resistant Acinetobacter baumannii (XDRAB) is a growing and serious nosocomial infection worldwide, such that developing new agents against it is critical. The antimicrobial activities of the rhizomes from Zingiber officinale, known as ginger, have not been proven in clinical bacterial isolates with extensive drug‐resistance. This study aimed to investigate the effects of four known components of ginger, [6]‐dehydrogingerdione, [10]‐gingerol, [6]‐shogaol and [6]‐gingerol, against clinical XDRAB. All these compounds showed antibacterial effects against XDRAB. Combined with tetracycline, they showed good resistance modifying effects to modulate tetracycline resistance. Using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging method, these four ginger compounds demonstrated antioxidant properties, which were inhibited by MnO₂, an oxidant without antibacterial effects. After the antioxidant property was blocked, their antimicrobial effects were abolished significantly. These results indicate that ginger compounds have antioxidant effects that partially contribute to their antimicrobial activity and are candidates for use in the treatment of infections with XDRAB. Copyright © 2010 John Wiley & Sons, Ltd.     

6-gingerol prevents patulin-induced genotoxicity in HepG2 cells

Patulin (PAT) is a mycotoxin produced by several Penicillium, Aspergillus and Byssochlamys species. Since PAT is a potent genotoxic compound, and PAT contamination is common in fruits and fruit products, the search for newer, better agents for protection against genotoxicity of PAT is required. In this study, the chemoprotective effect of 6-gingerol against PAT-induced genotoxicity in HepG2 cells was investigated. The comet assay and micronucleus test (MNT) were used to monitor genotoxic effects. To further elucidate the underlying mechanisms, the intracellular generation of reactive oxygen species (ROS) and level of reduced glutathione (GSH) were tested. In addition, the level of oxidative DNA damage was evaluated by immunocytochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG). The results showed that 6-gingerol significantly reduced the DNA strand breaks and micronuclei formation caused by PAT. Moreover, 6-gingerol effectively suppressed PAT-induced intracellular ROS formation and 8-OHdG level. The GSH depletion induced by PAT in HepG2 cells was also attenuated by 6-gingerol pretreatment. These findings suggest that 6-gingerol has a strong protective ability against the genotoxicity caused by PAT, and the antioxidant activity of 6-gingerol may play an important part in attenuating the genotoxicity of PAT.     

Antibacterial, partially acetylated oligorhamnosides from Cleistopholis patens

Three new (1-3) and five known (4-8) partially acetylated oligorhamnoside derivatives were obtained from Cleistopholis patens via high-throughput natural products chemistry procedures. The rapid structure elucidation and dereplication were performed primarily utilizing a capillary-scale NMR probe and LR-/HRESIMS spectroscopic methods. Compounds 1, 2, and 6 were found to possess significant in vitro antibacterial activity against the Gram-positive bacteria methicillin-resistant Staphylococcus aureus ATCC 33591 and S. aureus 78-13607A with MICs of < or =16 microg/mL. Furthermore, 2 and 6 were found to show significant in vitro antibacterial activity against an expanded panel of Gram-positive pathogens including either ATCC strains or well-characterized clinical isolates from the global SENTRY Antimicrobial Surveillance Program.