Chemical composition and antioxidant activity of a Lebanese plant Euphorbia macroclada schyzoceras

Objective

To determine the chemical composition, total phenolic and total flavonoid contents of the crude extracts from leaves and stems of a Lebanese plant Euphorbia macroclada schyzoceras (E. macroclada), and to evaluate their antioxidant potential using DPPH, H₂O₂, and chelating of ferrous ions tests.

Methods

Quantification of the total phenolic and total flavonoid contents of the crude extracts from leaves and stems and the antioxidant activities were evaluated using spectrophotometric analyses. The chemical composition has been estimated using different techniques such as IR, LC/MS and NMR.

Results

Ethanolic extract from leaves of E. macroclada was better than aqueous extract and showed higher content in total phenolic and total flavonoid than found in the stems. On the other hand, using DPPH and H₂O₂ tests, this extract from leaves showed higher antioxidant capacity than aqueous extract. However, using the chelating of ferrous ions test, the antioxidant activity of the aqueous extract of both stems and leaves was stronger than that of ethanolic once. The chemical composition of the whole plant showed the presence of some aromatic compounds and fatty acids.

Conclusions

Both ethanolic and water extracts from both parts of this plant are effective and have good antioxidant power. So, this plant can be used in the prevention of a number of diseases related to oxidative stress.     

In Vitro Study to Evaluate Antibacterial and Non-haemolytic Activities of Four Iranian Medicinal Plants

Objective:

Aqueous extracts of four medicinal plants including Ferula gummosa, Echinophora orientalis, Nasturtium microphyllum and Verbascum thapsus were used to determine their antibacterial activities and minimum inhibitory concentration (MIC). The aim of this study was to assess antibacterial activity of extracts of four medicinal plants against a Gram-positive and a Gram-negative bacteria (Staphylococcus aureus PTCC1431, and Escherichia coli HP101BA 7601c).

Methods:

Radial diffusion assay was used to assess the antibacterial activity of extracted samples. Haemolysis assay was also used to examine their nontoxic effects on human red blood cells.

Results:

This study showed that all the mentioned plants have satisfactory antibacterial effects against both Gram-positive and Gram-negative bacteria. Minimum inhibitory concentration values of these samples were less than 750 μg/mL. In addition, no significant haemolytic activity was observed at their MIC values.

Conclusion:

The results of this study showed that all these studied plants have good potential for further studies for drug discovery.     

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

ObjectiveTo evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and methicillin resistance S. aureus.MethodsThe crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S. aureus and methicillin resistance S. aureus using agar well diffusion method.ResultsIn Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra.ConclusionsThe potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.     

肺部感染革兰阴性杆菌耐药性研究

目的：监测我院门诊及住院患者G^-杆菌分布和耐药性状况。方法：采用接种血平板、巧克力平板、中国蓝平板,按美国临床实验室标准化委员会（CLSI／NCCLS）标准,判断药敏试验。结果：碳青霉烯类仍是对革兰阴性杆菌（除嗜麦芽窄食单胞菌）抗菌作用最强的一类抗生素。头孢吡肟、头孢西丁对大肠埃希菌、肺炎克雷伯杆菌也有较强的抗菌作用,阿米卡星对革兰阳性菌也有较强的抗菌作用。结论：碳氨酶类仍是对革兰阴性杆菌作用最强的一类抗生素,尤其是治疗ESBLS（＋）阴性菌的首选药物,但对于嗜麦芽窄食单胞菌耐药率较高。     

2012年至2015年临床常见病原菌分布及耐药趋势分析

目的:分析我院4年来常见病原菌分布情况及其对抗菌药物的耐药情况,为区属机构及医院感染控制和临床合理应用抗菌药物及科学制定采购计划提供依据。方法:收集2012年至2015年我院临床送检标本分离的病原菌资料,动态比较分析病原菌构成比的变化和分布特征及抗生素耐药情况。结果:全院这4年共接收21 344个标本,共培养出致病菌4619株,其中G+菌1 338株,G-菌2 974株,真菌菌株307株。G-菌构成比高于G+菌。常见G-病原菌是假单胞菌属、大肠埃希氏菌、克雷伯菌属、不动杆菌属。常见G+病原菌是葡萄球菌属、链球菌属及肠球菌属。来源于不同标本的同种病原菌,其药敏结果趋势也不尽相同。这4年来,ESBLs阳性率(大肠埃希菌、肺炎克雷伯菌)有先抑后扬的趋势,哌拉西林和氨苄西林的抗菌活性最差,头孢呋辛、头孢噻肟、头孢哌酮和头孢曲松对肠杆菌科的抗菌效果一般,但头孢哌酮/舒巴坦对鲍曼不动杆菌具有很好的抗菌活性,头孢他啶对大肠埃希菌、铜绿假单胞菌及肺炎克雷伯菌都具有较好的抗菌活性,但对鲍曼不动杆菌抗菌活性最差。葡萄球菌对万古霉素、利奈唑胺、呋喃妥因、替考拉宁等最敏感,对复方新诺明及氨基苷类药物耐药率最高。肠球菌对多种抗生素耐药率高。结论:细菌的多重耐药日趋严重,通过对本院常见病原菌的耐药性趋势进行分析,可指导临床合理使用抗生素,提高药物敏感性,降低耐药性,同时降低医院感染率和病死率。     

The in-vitro antimicrobial activity of Abrus precatorius (L) fabaceae extract on some clinical pathogens

OBJECTIVES: To investigate the in-vitro antimicrobial activities of the extracts of Abrus precatorius on some clinical isolates as resistance to available and affordable antibiotics by these pathogens is on the increase. METHOD: In this study the antimicrobial effects of the extracts of Abrus precatorius from leaves, stem and the seed oil were tested against Staphylococcus aureus ATCC 25923, three clinical S. aureus isolates from different sources, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus anginosus (S.milleri), Bacillus subtilis, Corynebacterium spp (toxigenic strain of the mitis biotype), Escherichia coli ATCC 25922, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa as well as Candida albicans using the agar well diffusion technique. Aqueous and methanolic extraction, using the soxhlet extractor was carried out on all plant parts used while petroleum ether was the solvent used to extract the seed oil. To measure the MIC values, various concentrations of the stock, 512, 256, 128, 64, 32, 16, 8 and 4 microg/ml were assayed against the test bacteria. RESULT: At the different concentrations of the extracts used (512 microg/ml - 4 microg/ml), Staphylococcus aureus was the most sensitive organism with an MIC of 8 ug/ml for the leaf extract. Extract from the stem and seed oil were potent against some of the gram-positive bacteria and Candida albicans but not against S anginosus, E. faecalis and gram-negative bacteria tested. The pH of the extracts ranged between pH5 and pH8. This study demonstrates that Abrus precatorius particularly the seed oil has a potent antimicrobial activity. CONCLUSION: The results substantiate the ethno botanical use of different parts of Abrus precatorius for the treatment of various bacteria-related diseases. Topical application of Abrus precatorius extracts in ointments may be recommended especially for treating superficial infections caused by Staphylococcus aureus.     

Antidiarrheal and antimicrobial profiles extracts of the leaves from Trichilia emetica Vahl.(Meliaceae)

Objective:To evaluate and-diarrhoeal and antimicrobial activities of the bioactive fraction of Trichilia emetica in order to provide a scientific basis for the management of gastroenteritis in Burkina Faso.Methods:To do this,polyphenols content of extract and fractions were investigated.FolinCiocalteu,AlCl_3 methods and tannic acid respectively were used for polyphenols content.The in vivo antidiarrhocal activity was done using Swiss albino mice of both sexes.In vitro antimicrobial activity(disc-diffusion assay,minimum inhibitory concentration and minimum microbicidal concentration or minimal bactericidal concentration) was assessed using seven bacteria strains(Gram-negative and Gram-positive).Results:About our study,it was found that ethyl acetate fraction effective attenuation factior(EAF) elicits the higher total phenolics and total flavonoids contents compared to the extracts of leaves of Trichilici emetica.EAF of Trichilia emetica Vahl..has positive effects in a dose dependent manner against diarrhoea induced by castor oil in experimental mice.The bioactive fraction also showed good antimicrobial activity against all tested Gram-negative and Grampositive bacteria strains.It was shown that experimental bacteria strains were more sensitive to the EAF effect compared to the ciprofloxacin.Conclusions:The obtained results allow justifying the traditional uses of Trichilia emetica and possess good antidiarrhoeal and antimicrobial activities of EAF from Trichilia emetica.Results of the present study have clearly supported the utilization of Trichilia emetica in Burkina Faso traditional medicine.     

Antimicrobial,hemagglutination and phytotoxic activity of crude ethanolic and aqueous extracts of Seriphidium kurramense

OBJECTIVE

To investigate the antimicrobial activity, hemagglutination and phytotoxic activity of crude ethanolic and aqueous extracts of Seriphidium kurramense.

Antioxidant and antibacterial activity of different parts of Leucas aspera

Objective

To evaluate antioxidant, antimicrobial and cytotoxic activity of different parts (root, flower, leaf and stem) of Leucas aspera (L. aspera) (Labiatae).

Methods

Different parts of L. aspera were extracted with 80% (v/v) methanol. The methanol extracts were subjected to antioxidant, antimicrobial and brine shrimp lethality assay.

Results

All the extracts showed moderate to potent antioxidant activity, among which the root extract demonstrated the strongest antioxidant activity with the IC₅₀ value of 6.552 µg/mL. Methanol extract of root possessed antioxidant activity near the range of vitamin E and thus could be a potential rich source of natural antioxidant. In case of antimicrobial screening, crude extracts of root, flower, leaf and stem showed notable antibacterial activity against tested microorganisms. The root extract showed the highest mean zone of inhibition ranging from 9.0–11.0 mm against tested microorganisms, at a concentration of 100 mg/mL. In the brine shrimp lethality bioassay, it was evident that the methanol root extract did not show significant toxicity. The LC₅₀ value for 12 h and 24 h observation was 2.890 mg/mL and 1.417 mg/mL, respectively.

Conclusions

The present finding suggests that the methanol root extract of L. aspera could be developed as pharmaceutical products.     

Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

ObjectiveTo investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis.MethodsAgar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts.ResultsMethanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth.ConclusionsThe efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.     

Antioxidant and antimicrobial properties of Litsea elliptica Blume and Litsea resinosa Blume (Lauraceae)

ObjectiveTo investigate antioxidant and antimicrobial activities of two plant species, Litsea elliptica (L. elliptica) and Litsea resinosa (L. resinosa).MethodsIn vitro method -2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was conducted for antioxidant activity determination while antimicrobial assay consisted of agar well diffusion assay and mycelial radial growth assay.ResultsMethanol extracts of root and stem of L. elliptica and L. resinosa exhibited the highest antioxidant activity with EC₅₀ of 23.99, 41.69, 11.22 and 35.48 mg/L respectively. All methanol extracts of L. resinosa as well as root extracts from L. elliptica showed significant scavenging activity. Hexane extract from stem of L. resinosa presented the largest inhibition zone in Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli while chloroform extract from inner bark of L. resinosa showed major inhibition towards Gram-positive bacteria Bacillus subtilis. Essential oils from the root of both species showed significant antifungal activities which are 80.11% and 66.85% respectively.ConclusionsOverall, methanol extracts from root and stem of both species showed antioxidant activity comparable to standard butylated hydroxytoluene. Extracts from L. resinosa demonstrated stronger antimicrobial properties compared to that from L. elliptica.     

Studies on the antibacterial activity of Khaya senegalensis [(Desr.) A. Juss)] stem bark extract on Salmonella enterica subsp. enterica serovar Typhi [(ex Kauffmann and Edwards) Le Minor and Popoff]

ObjectiveTo study the phytochemical screening and antibacterial activity of the stem bark extracts of Khaya senegalensis (K. senegalensis) against Salmonella enterica subsp. enterica serovar Typhi.MethodsThe plant components were extracted using methanol, ethanol and water. The phytochemical screening of the stem bark extracts were carried out using a standard method. The antibacterial assay of the stem bark extracts against Salmonella Typhi (S. Typhi) using the agar well diffusion method with different concentrations of 50, 100, 200, 400 and 500 mg/mL and the corresponding concentrations of the control was carried out and the result compared with a standard antibiotic, amoxicillin as the control.ResultsThe results obtained from the phytochemical screening of the three plant bark extracts of K. senegalensis showed 10 plant secondary metabolites including saponins, tannins, reducing sugars, aldehyde, phlobatannins, flavonoids, terpenoids, alkaloids, cardiac glycoside and anthroquinones. The ethanol and aqueous extracts showed antibacterial activities against S. Typhi at concentration of 50 mg/mL with the zone diameter of inhibition (ZDI) of 14 mm and 15 mm respectively. The ethanol and aqueous extracts also showed zone diameter of inhibition of 23 mm and 25 mm respectively at 250 mg/mL and 27 mm each at 500 mg/mL. The ethanol and aqueous stem bark extracts gave the highest ZDI at 500 mg/mL while 100 mg/mL gave the least ZDI for ethanol extract and 50 mg/mL for the aqueous extract. This was followed by 400 mg/mL that gave 24 mm ZDI of the aqueous extract and 27 mm of the ethanol extract. The methanol extract showed intermediate susceptibility evidenced by ZDI of 10 mm at 100 mg/mL concentration. The methanol extract also showed antibacterial activity of 24 mm ZDI against the test organism at a higher concentration of 250 mg/mL and 26 mm at 500 mg/mL concentration. The methanol, ethanol and aqueous extracts displayed antibacterial activities against S. Typhi with a statistical significant difference at (P≤0.05). The extracts compared favourably with the standard antibiotic, the control. The minimum inhibitory concentration of the extracts was 250, 200, 200 and 100 mg/mL for methanol, ethanol, aqueous extracts and amoxicillin (control) respectively. The minimum lethal concentration of the extracts was 250, 250, 400 and 200 mg/mL for methanol, ethanol, aqueous extracts and control respectively.ConclusionsThe antibacterial properties of K. senegalensis stem bark extract can be harnessed for the production of new antibiotics or the enhancement of already existing antibiotics.     

皮寒药不同提取液体外抗菌作用研究

目的:研究皮寒药全草水提液、乙醇提取液的体外抗菌作用.方法:采用纸片扩展法和2倍递增稀释浓度法检测皮寒药提取液的最低抑菌浓度( MIC)及测定其对5种菌种的抑菌率.结果:皮寒药水提液、乙醇提取液对表皮葡萄球菌的生长有明显的抑制作用,MIC均为25μg/mL;皮寒药乙醇提取液( 100μg/mL)对金色葡萄球菌有一定的抑制作用,其抑制率88.57％;皮寒药水提液(12.5μg/mL)和乙醇提取液(12.5μg/mL)对表皮葡萄球菌的抑菌率分别为80.39％、32.68％.结论:皮寒药水提液和乙醇提取液对表皮葡萄球菌有明显抑菌作用,且水提液比乙醇提取液的抑制作用强;乙醇提取液对金色葡萄球菌表现出抑菌作用,但药物浓度较大.皮寒药水提液和乙醇提取液在实验药物浓度下对绿脓杆菌、大肠杆菌及沙门氏菌无明显抑制作用.     

2616株临床分离菌菌群和耐药性分析

目的:了解临床分离出的细菌菌群和耐药性,为细菌性感染的诊断和治疗提供依据。方法:用常规手工方法分离鉴定细菌,药敏试验采用微量稀释法(MIC)测定抗菌药物敏感性。结果:分离出的2616株细菌中,革兰氏阳性菌占34.63%,革兰氏阴性菌占49.77%。常见的G+菌为凝固酶阴性葡萄球菌、金黄色葡萄球菌、肠球菌和肺炎球菌;常见的G-菌主要为大肠埃西菌、克雷伯菌属。耐甲氧西林金黄色葡萄球菌(MRSA)占51.06%、产超广谱β-内酰胺酶(ESBLs)大肠杆菌占52.17%、产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯氏菌占10.34%。结论:临床医生了解细菌菌群和耐药性特点,有助于临床医生合理、安全使用抗菌药物。     

重症医学科常见病原茵分布及其耐药性分析

目的探讨重症医学科（ICU）分离细菌菌株及细菌耐药情况,为重症医学科临床防治工作提供一定的参考依据。方法对2008年5月-2009年5月我院ICU所分离的细菌菌株、真菌及细菌耐药性进行回顾性分析。结果全年共分离获得菌株322株,分离菌仍以革兰阴性杆菌为主,有227株,占70,50％,主要为铜绿假单胞菌（25．6％）、鲍曼不动杆菌（14．91％）,其次为大肠埃希菌、肺炎克雷伯菌、嗜麦芽假单胞菌;革兰阳性球菌有5（1株,占15．53％,主要为金黄色葡萄球菌（4．9％）,其次分别为溶血性葡萄球菌、屎肠球菌和其他凝固酶阴性葡萄球菌;真菌有45株,占13．98％．体外药敏试验显示：革兰阴性杆菌呈多重耐药特性;嗜麦芽假单胞菌对亚胺培南／西司他丁、美罗培南天然耐药;万古霉素对金黄色葡萄球菌及表皮葡萄球菌均有很强抗菌活性,敏感性均达到100％,但屎肠球菌出现耐药菌株。结论我院重症医学科近1年来分离菌以革兰阴性杆菌为主,各种细菌呈多重耐药特性,应予以高度重视,临床工作中应注意合理使用抗生素,减少耐药菌的产生。     

Preliminary phytochemical screening and in vitro anti-Helicobacter pylori activity of acetone and aqueous extracts of the stem bark of Sclerocarya birrea (Anacardiaceae)

Helicobacter pylori antibiotic resistance and other problems associated with combination therapy have generated a considerable interest in the search for alternative therapeutic agents. In order to identify novel sources of such agents, the antimicrobial activity of five solvent extracts of the stem bark of Sclerocarya birrea was investigated against 30 clinical strains of H. pylori and a reference strain NCTC 11638 using standard microbiological techniques. Metronidazole and amoxicillin were included in these experiments as positive control antibiotics. The active phytocomponents were detected by TLC and indirect bioautography. All the extracts exhibited anti-H. pylori activity with zone diameters of inhibition between 0 and 21 mm. The acetone and aqueous extracts showed potent anti-H. pylori activity with minimum inhibitory concentration (MIC(90)) values ranging from 0.06-2.50 mg/mL, whereas those for the control antibiotics ranged from 0.001-5.0 mg/mL. The acetone extract was highly bactericidal at 1.2 mg/mL with complete elimination of the organisms within 18 h. The activity of both acetone and aqueous extracts was better than metronidazole (p<0.05). Most of the active phytocomponents were located in the acetone extract; R(f)≤0.62 with >90% inhibition. These results demonstrate that the acetone and aqueous extracts of S. birrea may contain compounds with therapeutic activity; therefore, they may represent potential sources of new anti-H. pylori regimen.     

老年患者下呼吸道感染病原菌分布和耐药性分析

目的:了解我院老年患者下呼吸道感染病原菌分布及其耐药性。方法:对2005年1月～2006年1月老年患者深部痰细菌培养及药敏试验结果进行回顾性分析。结果:472例痰标本中376例培养阳性,阳性率为79.7%;376例阳性标本中检出病原菌396株,其中革兰阴性杆菌270株(68.2%),革兰阳性球菌71株(17.9%),真菌55株(13.9%);铜绿假单胞菌居首位(30.8%);肺炎克雷伯菌和大肠埃希菌的ESBLs阳性率分别为14.7%和20.8%;药敏试验结果显示,亚胺培南对肠杆菌科细菌保持100.0%的抗菌活性;铜绿假单胞菌对多种抗菌药物敏感性下降,出现20.0%对亚胺培南耐药株;葡萄球菌属对万古霉素一致敏感。结论:老年患者下呼吸道感染以革兰阴性杆菌为主,而且耐药性较强,临床微生物室应加强病原菌及其耐药性的监测,以指导临床合理使用抗菌药物。     

某些喀麦隆食用植物对多重耐药革兰氏阴性菌的抗菌及抗生素增强活性

Objective:To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant(MDR) phenotypes.Methods:The antimicrobial activity of the extracts was performed using the broth microdilution method.The phytochemical screening of these extracts was also performed using standard methods.Resutts:Ocimum basilicum,Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria.The extracts from G.africanum and E.robusta were the most active with the lowest minimal inhibitory concentration of 64 μg/mL on Escherichia coli AG100 A for both extracts and also against Klebsiella pneumoniae K24 for G.africanum.When tested in the presence of phenylalanine-arginine β-Naphtylamide(PA β N),an efflux pump inhibitor,the extract of Thymus vulgaris and E.Robusta showed the best activities on most tested strains.E.Robusta extract showed good synergistic effects,improving the activity of commonly used antibiotics in about 85%of cases.Conclusion:The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.     

人工合成多肽P12体外杀菌作用的研究

目的对人工设计并合成的P12多肽进行体外杀菌活性的研究。方法从NCBI网站中找到具有代表性的抗菌多肽作为合成P12多肽的模板,利用琼脂铺板法将不同浓度的P12与6种细菌作用后,计算P12对6种细菌杀菌率。结果 P12对革兰阳性菌（金黄色葡萄球菌、枯草杆菌、炭疽杆菌）具有较强杀菌活性,其LD99在20~400μg/ml。对革兰阴性菌（大肠杆菌、绿脓杆菌、变形杆菌）杀菌活性较弱,其LD99约为1 200μg/ml。结论人工设计合成的P12对革兰阳性细菌具有较强的杀菌活性,对革兰氏阴性细菌也具有杀菌活性。     

Bactericidal activity of organic extracts from Flourensia cernua DC against strains of Mycobacterium tuberculosis

BACKGROUND: Tuberculosis is a chronic disease caused mainly by Mycobacterium tuberculosis. The emergence of antibiotic-resistant strains of this species underscores the need for novel effective drugs against resistant mycobacteria as first-line antituberculosis medications. METHODS: Crude aqueous (obtained by decoction, in accordance with the traditional mode of preparation), methanol, acetone, and hexane extracts from aerial parts of Artemisia ludoviciana Nutt., Chenopodium ambrosioides L., Marrubium vulgare L., Mentha spicata L., and Flourensia cernua DC were assessed for their ability to either inhibit the growth of or kill M. tuberculosis strains H37Rv and CIBIN:UMF:15:99, the former being sensitive to, and the latter resistant to, streptomycin, isoniazide, rifampin, ethambutol, and pyrazinamide. These five plant species are used in Mexico to treat respiratory disorders. RESULTS: Flourensia cernua was the uniquely active plant among those evaluated. Its hexane and acetone extracts not only inhibited the growth of but killed M. tuberculosis. The hexane extract showed a minimal inhibitory concentration (MIC) of 50 and 25 microg/mL against sensitive and resistant strains, respectively; the acetone extract was active against only CIBIN:UMF:15:99 (MIC = 100 microg/mL). CONCLUSIONS: The hexane extract from F. cernua leaves could be an important source of bactericidal compounds against multidrug-resistant M. tuberculosis.