Anti-Diabetic Activity of an Extract of Syzygium Jambolanum - A Review

Syzygium jambolanum is a promising natural treatment for diabetes.The potential benefits of S jambolanum for diabetes include lowering blood sugar levels,increasing insulin sensitivity,protecting pancreatic beta cells,and slowing the absorption of glucose into the bloodstream.The anti-diabetic activity of the crude extract of S jambolanum was evaluated in L6 myotubes and the lipid deposition in tissue was measured using Nile red Staining.Nile red staining confirmed that a considerable quantity of lipids had been deposited in the tissue treated with a crude extract of S jambolanum,comparable to the quantity of lipids deposited with a standard drug known as Rosiglitazone.This study analyzed the anti-diabetic activity of a crude extract of S jambolanum to understand its potential as a feedstock for extracting bioactive constituents to screen for bioactive molecules in the treatment of diabetes.

丁香 [Syzygium aromaticum (L.) Merr .et Perry]挥发油中天然抗菌成分研究(英文)

研究结果表明 ,丁香 [Syzygiumaromaticum (L .)Merr .etPerry]挥发油及其衍生物均可抑制黑曲霉(Aspergillusniger)和扩展青霉 (Penicilliumexpansun) 的生长 ,丁香挥发油对黑曲霉的最小抑菌浓度为 5 0 % ,对扩展青霉的最小抑菌浓度为 2 5 % ;丁香挥发油衍生物对黑曲霉的最小抑菌浓度为 2 5 % ,对扩展青霉的最小抑菌浓度为 2 0 %。用GC MS详细分析了丁香挥发油的化学成分 ,共鉴定了 2 0个化合物 ,其中主要成分为丁香酚 ,含量占挥发油成分总量的6 8.0 2 78%。

Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes

Objective:To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris(P.sylvestris)and Syzygium aromatkum(S.aromaticum)against Aedes aegypti(A.aegypti)and Culex quinquefasciatus(C.quinquefasciatus).Method:The chemical composition of the essential oils of both plants was determined using GCMS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A.aegypti and C.quinquefasciatus in accordance with the standard protocol.Results:The results as determined by GC-MS showed that oil of S.aromaticum has eugenol(80.5%)as its principal constituent while P.sylvestris has 3-Cyclohexene-1-methanol,.alpha.,.alpha.4-trimethyl(27.1%)as its dominant constituent.Both oils achieved over 85%larval mortality within24 h.The larvae of A.aegypti were more susceptible to the oils[LC_(50)(S.aromaticum)=92.56 mg/L,LC_(50)(P.sylvestris)=100.39 mg/L]than C.quinquefasciatus[LC_(50)(S.aromaticum)=124.42 mg/L;LC_(50)(P.sylvestris)=128.00 mg/L].S.aromaticum oil was more toxic to the mosquito larvae than oil of P.sylvatris but the difference in lethal concentrations was insignificant(P>0.05).Condusioii:The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control.

Effects of the Syzygium aromaticum L. extract on antioxidation and inhibition of matrix metalloproteinase in human dermal fibroblast

Objective: To investigate cosmetic potential of Syzygium aromaticum L.(S. aromaticum L.) and to determine its antioxidant and anti-wrinkling effects. Methods: Using highperformance liquid chromatography, eugenol component was quantitated. The antioxidant activity of S. aromaticum L. was analyzed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging and superoxide dismutase like activities. To determine cell viability, elastase and matrix metalloproteinase-1(MMP-1) activity, human dermal fibroblasts(HS68) were treated with S. aromaticum L. The inhibitory effect of S. aromaticum L. on tumor necrosis factor alpha induced MMPs expression in HS68 was analyzed by realtime-PCR. Results: The eugenol content was confirmed in S. aromaticum L. S. aromaticum L. was observed to have high 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and superoxide dismutase like activity. S. aromaticum L. had no cytotoxicity against the HS68 and dose-dependently increased elastase inhibition. Moreover, S. aromaticum L. significantly decreased MMP-1 content and inhibited gene levels of MMP-1, MMP-2, MMP-3 and MMP-9. Conclusions: The findings suggest that S. aromaticum L. has great potential as a cosmeceutical ingredient with antioxidant and antiwrinkling effects.

Ameliorative Effects of <i>Syzygium aromaticum</i>Essential Oil on Fertility in Male Rats Exposed to Manganese

Introduction: Several substances were likely to cause the decline in male fertility which could go up to the complete sterility. The aim of this study was to assess the effects of Syzygium aromaticum essential oil on fertility in male rats exposed to manganese. Materials and Methods: Twenty four male rats, 6 months old, were divided into 2 groups;12 rats in one group received, by oral route, a water containing manganese chloride tetrahydrate (MnCl2·4H2O) is at the dose of 4.79 mg·ml-1 for 12 weeks. The group of control male rats received a distilled water in the same conditions. After a period of experimentation, each group was divided into two subgroups of 6 rats which received daily, by intraperitoneal way, a 0.1 mg/kg body weight, of Syzygium aromaticum essential oil. Results: After a chronic exposure, microscopic examination of the testes showed degeneration of the seminiferous tubules and the gremlin cell. Seminal parameters indicated a decrease in the sperm levels (21.3 × 106 cells/ml) and a rise of morphological abnormalities (66.1%). However, intraperitoneal administration of essential oil extracted from the flower buds of Syzygium aromaticum, during 3 weeks, to the rats previously intoxicated with Mn, showed a significant rising of sperm concentration (61.2 × 106 cells/ml) and a reduction of morphological abnormalities (10.8%). These changes were associated with a significant regeneration of seminiferous tubules and interstitial cells. Conclusion: This study revealed an ameliorative effect of essential oil Syzygium aromaticum in testicular tissue and the sperm quality.

Repellent and Fumigant Effects of Essential Oil from Clove Buds Syzygium aromaticum L. against Tribofium castaneum （Herbest） （Coleoptera： Tenebrionidae）

Essential oil from clove buds Syzygium aromaticum L. Merr. ＆ Perry （Myrtaceae） was extracted using petroleum ether in Soxhlet apparatus. The resultant oil contained eugenol （48.92%）, caryophyllene （18.55%）, α-caryophyllene （3.25%）, eugenol acetate （23%）, cis-13-docosenamide （3.2 1%）, presenting more than 96% of the oil. This oil was examined as a fumigant and repellent agent against adults of the red flour beetle, Tribolium castaneum. Data showed that various concentrations of the oil have revealed dramatic repellent activity against the tested insect, where it gave 100% repellency by 1.0, 0.8, and 0.2% clove oil at 4, 8, 10 min, respectively. The RTs0 and RT95 were 1.1 and 8.0 min at 0.2% and 0.4, 2.6 min at 0.8%, respectively. In addition, fumigation assay has also exhibited strong fumigant activity toward the adults of T. castaneum. At 100 μL oil/L air, mortality was 75, 80 and 100% after 6, 7, and 8 days exposure period with LCs0 and LC95 17 and 70 μL/L air, respectively. The utilization of clove oil for its potential effects against stored product insect is discussed.

The Effect of Mixture of Alpinia Galanga, Eurycoma Longifolia Jack and Syzygium Aromaticum Crude Extract on the Growth of Saccharomyces Cerevisiae and Escherichia Coli

Alpinia galanga, Eurycoma longifolia Jack and Syzygium aromaticum have been widely used in traditional medicine for decades. Antimicrobial activities for individual crude extract were well established. Crude methanolic extracts of Alpinia galanga, Eurycoma longifolia Jack and Syzygium aromaticum and the combination for all extracts were tested using well diffusion techniques against Saccharomyces cerevisiae （ATCC 9763） and Escherichia coli （ATCC 25922）. The mixed extracts were prepared based on the concentration ratio of 50 μg/μL which are 1：1, 1：1：1 and 1：2：2. Single Syzygium aromaticum extract showed higher inhibition zone on Saccharomyces cerevisiae compared to Escherichia coli. There is reduction in diameter of inhibition zone for single extract and mixture extracts either in combination of two or three extracts tested on Saccharomyces cerevisiae and Escherichia coli growth but they are not significant. In conclusion, Syzygium aromaticum showed highest activity against Saccharomyces cerevisiae and Escherichia coli. Reduction in diameter of inhibition zone indicated that Alpinia galanga and Eurycoma longifolia Jack extracts had antagonistic effect with Syzygium aromaticum.

Safety Assessment and Potential Anti-Inflammatory Effect of Ethanolic Extract of <i>Syzygium aromaticum</i>in Albino Rats

The present study was undertaken to investigate the effect of the ethanolic extract of Syzygium aromaticum to albino rats. Forty eight Albino rats were employed to test the safety and the anti-inflammatory effect of the extract. Safety of the extract was examined on experimental animal’s model at three dose levels of the extract orally in daily doses for three weeks. Effects of S. aromaticum on rats revealed no significant effect on biochemical or haematological parameters. The anti-inflammatory effect of the extract was tested in four equal groups;groups 1 and 2 were treated with 250 and 500 mg/kg of the extract, respectively, group 3 was treated with indomethacine and group 4 was the untreated control. Carrageenan was used as an acute form inducer of inflammation. Indomethacine, the non-steroidal anti-inflammatory drugs (NSAIDs), was used as a reference compound. Oedema size was monitored at the 1st, 2nd, 4th, 6th and after 24 hours. The ethanolic extract of S. aromaticum showed significant (P 0.001) decreased in the oedema size at efficacy rates of 79.41%, 82.39% and 63.92% for the dose, 500 mg/kg body weight at the 2nd, 4th and 6th hour respectively higher than that produced by indomethacine.

Potential of <i>Syzygium aromaticum</i>(Clove) Leaf Extract on Immune Proliferation Response in Balb/c Mice Infected with <i>Salmonella typhimurium</i>

Background and Objective: Syzygium aromaticum is an immunomodulator with the main active compound eugenol which can stimulate the function of lymphocyte proliferation and macrophage production. Lymphocytes play an important role for body protection against infection. This study aims to analyze the effect of S. aromaticum extract to increase proliferation of lymphocytes, lymphoblasts and macrophage production in Balb/c mice infected with Salmonella typhimurium. Methodology: Mice strain Balb/c were divided into 4 groups: treatment group infected with S. typhimurium and control group (without treatment) to tested the activity of peritoneal macrophages. The treatment group was administrated by S. aromaticum leaf extract (15 mg, 75 mg, 150 mg/kgbw) for 12 days. Results: S. aromaticum leaf extract increased the proliferation activity (p Conclusion: Administration of S. aromaticum leaf extract increased the proliferation activity of lymphocytes, lymphoblasts and ROI secretion of macrophagesin Balb/c mice infected with S. typhimurium.

Biological Activity of <i>Syzygium aromaticum</i>and <i>Ravensara aromatica</i>Essential Oils from Madagascar and Their Possible Use against Postharvest Mango Anthracnose

The fungitoxicity of five Malagasy essential oils (Eos) against Colletotrichum asianum was assessed in terms of conidial germination and mycelial growth. Their effect on defense-related compounds content, physicochemical properties and anthracnose lesions in mango fruits was also determined. Four of the tested Eos were from Ravensara aromatica leaves, and the last Eo was extracted from clove leaves. Their chemical compositions were then determined through GC-MS analysis and the active compound of the most fungitoxic Eo was determined by testing the toxicity of its major component to C. asianums spore germination, mycelial growth and its ability to inhibit anthracnose development on mango fruits. The R. aromatica Eos tested were fungistatic to C. asianum, whereas clove Eo was fungitoxic and the 4 chemotypes of R. aromatica Eo exhibited variable inhibiting capabilities: 1) all tested doses of all Eos (112.5 and 225 μL/L of air) were effective against C. asianum mycelial growth (10% - 100% inhibition) but doses of 225 μL/L were more inhibitory than those of 112.5 μL/L, 2) Conidial germination was more resistant to Eos toxicity since only 225 μL/L of methyl eugenol chemotype of R. aromatica Eo, all tested doses of the sabinene chemotype of R. aromatica Eo and clove Eo were found inhibitory toward conidial germination of C. asianum. 30 μL/L of sprayed clove Eoweretested on inoculated mangoes and were found to be effective against anthracnose development without affecting the resorcinol content in mango peel and the physicochemical properties of mango pulp. Tests on the major components of clove Eo showed fungitoxic activities against mycelial growth and conidial germination of C. asianum similar to those of clove Eo.

Insecticidal Activity of the Powders Obtained from the Bauxite Red Mud, Zyzygium aromaticum and Citrus sinensis Peel Extracts on the Conservation of Corn against Sitophilus zeamais: Physicochemical Properties

The remarkable push of technologies increasingly recommends materials for their constructions.Hence the extraction of alumina is for different uses.The exploitation of bauxite pollutes the surrounding areas in this case the discharge of mud wheel.Furthermore,the excessive use of dangerous conventional synthetic insecticides continues to be in circulation in Cameroon despite the known adverse effects.These problems lead us to formulate bio insecticides from rejection of the extraction of alumina and extracts of S.aromaticum and Citrus sinensis which respectively offer us essential oils eugenol and limonene having insecticidal properties against the main insects,pests of corn stocks,Sitophilus zeamais.From the kinetic point of view of the adsorption of the extracts of eugenol,limonene and their association by the red mud,the adsorption curve shows that the Eu/Li mixture(30/70)is better by 0.36 mg/g during the 24 h.The results showed a high toxicity of the Eu-Li binary mixture of ratio 30/70 with respective mortality rates of 95.88%after 8 days of exposure to the concentration of 5 mL/L on the adults of Sitophilus zeamais.The other composites induce an average rate of 80%.The results from the physicochemical analysis of corn before and after treatment with formulated insecticides showed a slight loss in nutritional quality of 14.90%in ash,12.5%in protein,16.14%in lipids and 13.63%in total sugars for 180 days.The powdery formulation from red mud and Eu-Li(30/70)mixture can therefore ensure the protection of corn stocks against Sitophilus zeamais in a farming environment.

Safety evaluation of an anti-haemorrhoid(pile)herbal recipe(locally called‘Agbo jedi-jedi’)of Southwestern Nigeria using animal genetic assays

Objective:In this study,an anti-haemorrhoid herbal recipe containing bark of Alstonia boonei and dried cloves–Syzygium aromaticum was investigated for cytogenotoxicity,mutagenicity and histopathological effects following the micronucleus and sperm morphology assays using Wistar albino rats.Methods:The rats were administered anti-haemorrhoid herbal recipe at 25.0%,50.0%and 100.0%,while distilled water and 0.05%sodium azide were the negative and positive controls,respectively.Phytochemicals in the herbal recipe were elucidated using the Fourier Transform Infrared(FTIR)and Gas Chromatography Flame Ionization Detection(GC-FID)techniques.Results:In the treated rats,there was increase in body weight,cells division inhibition,micronucleated polychromatic/normochromatic erythrocytes(MNPCEs&MNNCEs)and abnormal sperm cells were significantly induced at 100.0%(P<0.05),whereas 25.0%herbal recipe promoted cell division.The herbal recipe at 50.0%and 100.0%did not cause any histopathological damages on the liver,kidney and testis except at 25.0%.Polyphenolics,terpenoids and alkaloids were detected in this anti-haemorrhoid herbal recipe which could be cytotoxic,clastogenic and spermatotoxic at a high concentration(100.0%).Conclusion:These results necessitate regulation and control of consumption of the anti-haemorrhoid herbal recipe by people through the authorized government agencies in Nigeria.

福田河白菊与其他菊花栽培品种HPLC指纹特征研究

目的比较不同产地各种菊花栽培品种的HPLC指纹特征,为构建福田河白菊的HPLC指纹图谱奠定基础。方法采用INERTSILC18柱,乙腈-水(含2%四氢呋喃,0.1%三氟醋酸)为流动相,梯度洗脱,体积流量1mL/min;柱温30℃,对不同菊花栽培品种以及同属其他相关种进行对比色谱分析。结果构建了菊花的HPLC指纹图谱模式,该模式显示不同产地菊花品种的HPLC图谱具有较高的相似性,有15个共有峰,其中4个为10强峰,2个为10强峰或次强峰。指纹数据反映了各品种菊花在地域和亲缘关系上的联系以及各自独特的特征。结论该色谱系统可以用于构建福田河白菊、湖北金菊等不同菊花品种的指纹图谱。

基于指纹图谱结合化学模式识别法评价不同产地蒲桃叶药材质量

建立蒲桃叶HPLC指纹图谱并指认其中2种成分,结合主成分和聚类分析对不同产地蒲桃叶综合品质进行分析,为其质量评价提供理论和数据基础。采用Sonoma C_(18)(2)(4.6 mm×250 mm,5μm)色谱柱,0.1%甲酸水-甲醇为流动相,梯度洗脱,检测波长290 nm,流速1.0 mL/min,进样量10μL,柱温30℃,采用《中药色谱指纹图谱相似度评价系统(2012版)》进行相似度评价,确定共有峰。采用SPSS 22.0统计软件进行聚类分析、主成分分析,建立不同产地蒲桃叶的综合评价表。10批蒲桃叶HPLC指纹图谱标定12个共有峰,指认了2种化学成分,1号峰为没食子酸,4号峰为对羟基苯甲酸。10批蒲桃叶可聚为三类,茂名产蒲桃叶聚为一类,肇庆蒲桃叶聚为一类,其余地区产蒲桃叶聚为一类。主成分、因子分析表明肇庆蒲桃叶质量总体优于其他产地,1、2、4、5、6、12共有峰可作为蒲桃叶质量评价主要成分。10批样品相似度为0.591~0.994,表明不同批次蒲桃叶样品存在差异。所建HPLC指纹图谱和含量测定方法简便、稳定性好,结合化学模式可为蒲桃叶药材质量控制与评价提供参考。

NaCl处理对刺槐和丁香种子萌发的影响

设置0.2%、0.4%、0.6%和0.8%4种浓度的NaCl溶液,对刺槐和丁香种子的萌发进行盐胁迫处理。结果表明,随着NaCl浓度的升高,刺槐和丁香种子的发芽率、发芽势、发芽指数和活力指数均呈下降趋势。综合分析认为:刺槐种子的耐盐性比丁香种子的耐盐性强,刺槐种子能忍耐的盐胁迫浓为0.6%以下,丁香种子能忍耐的盐胁迫浓为0.2%以下。

NaCl处理对刺槐和丁香种子发芽苗生长的影响

设置0.2%、0.4%、0.6%和0.8%四种浓度的NaCl溶液,对刺槐和丁香种子发芽苗生长进行盐胁迫处理。结果表明,随着NaCl浓度的升高,刺槐和丁香种子发芽后幼苗的根长、苗长、鲜重呈下降趋势;刺槐种子发芽苗的耐盐性高于丁香种子发芽苗,刺槐种子和丁香种子能忍耐的盐胁迫浓度分别为0.6%以下、0.2%以下。

<i>In Vitro</i>Efficacy of Clove Oil and Eugenol against <i>Staphylococcus</i>spp and <i>Streptococcus mutans</i>on Hydrophobicity, Hemolysin Production and Biofilms and their Synergy with Antibiotics

The present study aimed to evaluate Syzygium aromaticum (clove) plant extract, clove oil and eugenol for their antibacterial activity and their potential to eradicate bacterial biofilms alone and in combination with antibiotics. Anti-bacterial efficacy of S. aromaticum extract, clove oil and eugenol was evaluated as minimum inhibitory concentration (MIC) and subsequently sub-MICs was selected for inhibition of virulence factors against test bacterial strains. Biofilm cultivation and eradication was assayed using XTT reduction in 96-well microtiter plate. Checkerboard method was used to study the interaction between essential oils and antibiotics. Staphylococcus aureus MTCC3160, Staphylococcus epidermidis MTCC435, Staphylococcus sciuri (SC-01), Staphylococcus auricularis (SU-01) and Streptococcus mutans MTCC497 were found strong biofilm former among all the test bacterial strains. The potency of test agents was found in the order of eugenol > clove oil > S. aromaticum methanolic extract. Sub-MIC (0.5 × MIC) of clove oil and eugenol showed a significant reduction in cell surface hydrophobicity (p < 0.05) and hemolysin production in the test bacterial strains. Eugenol showed no increase in sessile MIC (SMIC) against S. auricularis (SU-01), S. epidermidis MTCC435 and S. mutans MTCC497 compared to planktonic MIC (PMIC). Antibiotics (vancomycin and azithromycin) exhibited upto 1000-folds increased in SMIC compared to PMIC against all the test bacterial strains. Synergy was observed between eugenol and antibiotics (vancomycin/azithromycin) against all the test bacterial strains in both planktonic and sessile mode. Highest synergy was exhibited between eugenol and azithromycin in planktonic mode (FICI value 0.141). Further, microscopy also confirmed the spectacular effect of combination treatment on pre-formed S. aureus MTCC3160 and S. mutans MTCC497 biofilms. These findings highlighted the promising role of clove oil and eugenol alone and in combination on pathogenic bacterial biofilms.

丁香和瑞香狼毒提取物对苦瓜枯萎病菌抑菌机理初探

近年来,苦瓜因其独特的药理作用种植面积越来越大,但由于连作使得苦瓜枯萎病发病情况日趋严重,极大影响着苦瓜的产量及品质。试验以丁香(Syzygium aromaticum)、瑞香狼毒(Stellera chamaejasme)、羌活(Notopteryg iumincisum)、芫花(Daphne genkwa)、结香(Edgeworthia chrysantha)和八角(Illicium verum)等6种植物提取物为供试材料,测定其对苦瓜枯萎病菌(Fusarium oxysporum f.sp.momordicae)的菌丝生长速率、孢子萌发以及酶活性的影响,旨在筛选对苦瓜枯萎病菌高效抑制的植物源农药,为进一步开发植物源农药提供理论依据。结果表明,丁香和瑞香狼毒提取物在质量浓度为4.0 mg/mL时,抑菌率均达到了100%,在质量浓度为2.0 mg/mL时,抑菌率分别达到了100%、87.02%,丁香和瑞香狼毒提取物EC50值为0.2565、0.3548 mg/mL;且在质量浓度为4.0 mg/mL时,二者对苦瓜分生孢子萌发抑制率均达到了80%以上。丁香和瑞香狼毒提取物处理苦瓜枯萎病菌后,丙二醛含量、丙酮酸含量较对照组均有明显提高,几丁质酶活性较对照组明显降低,处理组菌丝中的可溶性蛋白明显低于对照组。综上,丁香和瑞香狼毒提取物对苦瓜枯萎病菌有良好的抑制效果,二者均可破坏病原菌的膜脂结构以及细胞壁结构,从而影响病原菌的正常生长。

黄土丘陵区典型人工幼林土壤水分特征

为明确黄土丘陵区典型人工幼林土壤水分时空变化特征,采用ECH2O土壤水分监测系统,基于标准径流小区坡面土壤水分观测方法,收集土壤水分及气象数据,分析了撂荒地与不同类型人工幼林土壤水分状况及时间稳定性。结果表明:(1)与撂荒地相比,人工幼林土壤含水量整体较低,且具有明显的季节性变化特征,变化趋势基本一致,均随降水量的增加(减少)而升高(降低);(2)不同类型人工林土壤水分垂直分布差异较大,相较于撂荒地,刺槐和油松在50 cm深度土层土壤含水量较低,在80—120 cm深度土层土壤含水量较高,丁香幼林土壤水分整体偏低;(3)油松和撂荒地土壤水分代表深度分别为:120 cm和80 cm,决定系数(R2≥0.9)和纳什系数(NSE≥-0.1)对该结果的评价显示土壤水分代表深度的选择均是可接受的,刺槐和丁香不同深度土层土壤水分差异较大。研究认为,在黄土丘陵区,人工幼林显著影响土壤水分垂直分布规律,土壤含水量整体呈低态势,相较于撂荒地,刺槐和丁香土壤水分变异性较大,油松较为稳定。

Inhibition of Escherichia coli nitroreductase by the constituents in Syzygium aromaticum

Gut bacterial nitroreductases play an important role in reduction of various nitroaromatic compounds to the corresponding N-nitroso compounds,hydroxylamines or aromatic amines,most of which are carcinogenic and mutagenic agents.Inhibition of gut nitroreductases has been recognized as an attractive approach for reducing mutagen metabolites in the colon,so as to prevent colon diseases.In this study,the inhibitory effects of 55 herbal medicines against Escherichia coli(E.coli)nitroreductase(EcNfsA)were examined.Compared with other herbal extracts,Syzygium aromaticum extract showed superior inhibitory potency toward EcNf-sA mediated nitrofurazone reduction.Then,the inhibitory effects of 22 major constituents in Syzygium aromaticum against EcNfsA were evaluted.Compared with other tested natural compounds,ellagic acid,corilagin,betulinic acid,oleanic acid,ursolic acid,urolith-in M5 and isorhamnetin were found with strong to moderate inhibitory effect against EcNfsA,with IC50 values ranging from 0.67 to 28.98 mol·L^(−1).Furthermore,the inhibition kinetic analysis and docking simulation demonstrated that ellagic acid and betulinic acid potently inhibited EcNfsA(Ki<2μmol·L−1)in a competitively inhibitory manner,which created strong interactions with the catalytic triad of EcNfsA.In summary,our findings provide new scientific basis for explaining the anti-mutagenic activity of Syzygium aromaticum,where some newly identified EcNfsA inhibitors can be used for developing novel agents to reduce the toxicity induced by bacteri-al nitroreductase.