茶皂素―金属复合抗菌剂的制备及抗菌性能研究

通过抑菌环法探讨了茶皂素、金属离子、茶皂素―金属复合抗菌剂对大肠杆菌和金黄色葡萄球菌的抗菌活性,考察了茶皂素纯度、浓度、金属离子种类等因素对抗菌剂抗菌活性的影响。结果表明,茶皂素的抗菌活性与单一的金属离子的抗菌活性相当,茶皂素对大肠杆菌的最低抑制浓度为5 mg/mL,对金黄色葡萄球菌的最低抑制浓度是10 mg/mL;茶皂素与金属离子复配抗菌活性具有协同效应,尤其茶皂素―锌复合抗菌剂对大肠杆菌的抑制效果大大加强。     

Synthesis,Characterization and Antibacterial Activity of New 5-Aryl Pyrazole Oxime Ester Derivatives

Eleven new 1-{5-[4-（benzyloxy）phenyl]-3-methyl-4,5-dihydropyrazol-l-yl} oxime ester dcrivatives were synthesized and characterized by elemental analysis, HRMS, ^1H NMR data. All the compounds were screened for their antibacterial potential in vitro against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results indicate that compounds 8c and 8f possess potent activity with the minimum inhibitory concentrations（MIC） of 1.562--3.125 ug/mL against all the four bacteria. Compounds 8c, 8e and 8f show moderate inhibition against the DNA gyrase（IC50=1.9--2.5 ug/mL）. On the basis of the biological activities, structure-activity relationship was discussed.     

微量热法研究头孢菌素对大肠杆菌微生物活性的影响

用微量热法测定了两种头孢菌素头孢哌酮钠(CFZ)和头孢哌酮钠舒巴坦钠(CFZ-SBT)在37 ℃时对大肠杆菌DH5α代谢作用的影响. 根据产热曲线分别获得了大肠杆菌DH5α在不同浓度的头孢哌酮钠和头孢哌酮钠舒巴坦钠作用下的生长速率常数(k)、抑制率(I)、最大产热功率(Pm)以及最大产热功率所对应的时间tm等热动力学参数. 研究结果表明, 头孢哌酮钠和头孢哌酮钠舒巴坦钠对大肠杆菌的致死量分别为0.1和0.25 μg/mL. 通过研究k, I, Pm, tm和浓度(c)间的关系发现, 舒巴坦钠的加入没有增加头孢哌酮钠对大肠杆菌DH5α的抑制作用.     

Cytotoxic lignans from the stems of Styrax camporum (Styracaceae)

An ethanolic extract from the stems of Styrax camporum Pohl (Styracaceae), a plant traditionally used for gastrointestinal diseases, was fractionated and subjected to flash chromatography and afforded two benzofuran lignans, egonol and homoegonol, and one furofuran lignan, (+/-)syringaresinol, which were identified by spectral data interpretation. Their cytotoxic activities against Hep-2 (larynx epidermoid carcinoma), HeLa (human cervix carcinoma) and C6 (rat glioma) cell lines were evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay at several concentrations for 24h. Activities could be observed for egonol against C6 (IC50 = 3.2 microg/mL) and Hep-2 (IC50 = 3.6 microg/mL) cell lines, and for homoegonol against C6 (IC50 = 4.9 microg/mL) and HeLa (IC50 = 5.3 microg/mL) cells.     

In vitro inhibitory properties of ferrocene-substituted chalcones and aurones on bacterial and human cell cultures

Two series of ten chalcones and ten aurones, where ferrocene replaces the C ring and with diverse substituents on the A ring were synthesized. The compounds were tested against two antibiotic-sensitive bacterial strains, E. coli ATCC 25922 and S. aureus ATCC 25923, and two antibiotic-resistant strains, S. aureus SA-1199B and S. epidermidis IPF896. The unsubstituted compound and those with methoxy substitution showed an inhibitory effect on all bacterial strains at minimum inhibitory concentrations ranging between 2 and 32 mg L(-1). For four of these compounds, the effect was bactericidal, as opposed to bacteriostatic. The corresponding organic aurones did not show growth inhibition, underscoring the role of the ferrocene group. The methoxy-substituted aurones and the unsubstituted aurone also showed low micromolar (IC(50)) activity against MRC-5 non-tumoral lung cells and MDA-MB-231 breast cancer cells, suggesting non-specific toxicity.     

Antimicrobial activity of globulol isolated from the fruits of Eucalyptus globulus Labill

An antimicrobial sesquiterpene was separated by bioassay-guided isolation from the petroleum ether fraction of the ethanol crude extract of Eucalyptus globulus Labill (Myrtaceae) fruits, and was identified as globulol by physicochemical properties and spectroscopic analysis. Mycelial growth method revealed that the median effective inhibitory concentration (IC50) values of globulol on Alternaria solani, Fusarium oxysporum f.sp. niverum, F. graminearum, Rhizoctonia solani and Venturia pirina were 47.1 microg mL(-1), 114.3 microg mL(-1), 53.4 microg mL(-1), 56.9 microg mL(-1), 32.1 microg mL(-1) and 21.8 microg mL(-1), respectively. MTT-colorimetric assay revealed that IC50 values of globulol on Xanthomonas vesicatoria and Bacillus subtilis were 158.0 microg mL(-1) and 737.2 microg mL(-1), respectively. The results indicated that globulol could be a main antimicrobial compound in the ethanol crude extract of E. globulus fruits.     

Studies on the potential antioxidant properties of Senecio stabianus Lacaita (Asteraceae) and its inhibitory activity against carbohydrate-hydrolysing enzymes

This study showed for the first time the antioxidant and hypoglycaemic properties of the methanol, n-hexane and ethyl acetate extracts from Senecio stabianus Lacaita, a plant that belongs to the Asteraceae family. The antioxidant activities were carried out using two different in vitro assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) (ABTS) test. The ethyl acetate extract showed the highest activity with inhibitory concentration 50% (IC(50)) values of 35.5 and 32.7?μg?mL(-1) on DPPH test and ABTS test, respectively. This activity may be related to a good total phenol and flavonoid content. All extracts were also tested for their potential inhibitory activity of α-amylase and α-glucosidase digestive enzymes. The n-hexane extract exhibited the highest α-amylase inhibition with an IC(50) value of 0.21?mg?mL(-1). Through bioassay-guided fractionation processes seven fractions (A-G) were obtained and tested. Based on the phytochemical analysis, the activity of n-hexane extract may be related to the presence of monoterpenes and sesquiterpenes.     

Synthesis, characterization, and antimicrobial evaluation of oxadiazole congeners

A series of 1,3-oxazole, 1,3-thiazole, isomeric 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,3,4-tetrazole heterocycles was synthesized. All the compounds shared as a common feature the presence of a 4-hydroxyphenyl substituent. The structures of the synthesized compounds were confirmed by MS, 1H-NMR, and elemental analysis. In vitro antimicrobial activity for all the newly synthesized compounds at concentrations of 200-25 μg/mL was evaluated against Gram+ve organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Gram-ve organisms such as Escherichia coli (E. coli), and the fungal strain Aspergillus niger (A. niger) by the cup plate method. Ofloxacin and ketoconazole (10 μg/mL) were used as reference standards for antibacterial and antifungal activity, respectively. Compounds 15, 16, and 20 showed notable antibacterial and antifungal activities at higher concentrations (200 μg/mL), whereas 17-19 were found to display significant antibacterial or antifungal activity (25-50 μg/mL) against the Gram+ve, Gram-ve bacteria, or fungal cells used in the present study.     

Evaluation of antibacterial effect and mode of Coptidis rhizoma by microcalorimetry coupled with chemometric techniques

In this study, the antibacterial effect and mode of Coptidis rhizoma on Escherichia coli was evaluated by microcalorimetry coupled with chemometric techniques. Using an isothermal microcalorimeter, the metabolic profiles of E. coli growth at 37 °C affected by 15 batches of C. rhizoma were measured. Through principal component analysis (PCA) on nine quantitative thermo-kinetic parameters obtained from the metabolic power-time profiles of E. coli, the antibacterial effects of C. rhizoma from various sources could be easily evaluated by analyzing the change of the two main thermo-kinetic parameters, growth rate constant k(2) and maximum heat-output power P(2)(m), in the second exponential phase of E. coli growth. Then, hierarchical clustering analysis (HCA) was carried out on the two parameters to distinguish those C. rhizoma samples in respect to their antibacterial effects. Clear results were obtained to show that all 15 C. rhizoma samples with different antibacterial effects could be successfully grouped in accordance with their origins. Ranked in decreasing order, the antibacterial mode of C. rhizoma samples that were from Sichuan province had the strongest antibacterial effects, followed by samples from Chongqing city and Hubei province. Our results revealed that the developed microcalorimetry with chemometric techniques had the potential perspective for evaluating the effect and mode of Coptidis rhizoma and other Chinese materia medicas.     

Herbicidal activity of curvuiinic acid isolated from Nimbya alternantherae

A phytotoxic compound, identified as 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (curvulinic acid), was isolated from liquid cultures of the phytopathogenic fungus Nimbya alternantherae. The activity of curvulinic acid on seed germination and seedling growth of Capsella bursa-pastoris was evaluated. Percentage seed germination of C. bursa-pastoris was decreased with increasing concentrations of curvulinic acid. The compound had stronger inhibitory effects on root length than shoot length. At a concentration of 600 microg x mL(-1), curvulinic acid caused 73.5% and 66.7% growth inhibition on roots and shoots with IC50 values of 204.7 and 281.1 microg x mL(-1), respectively. The finding of curvulinic acid in N. alternantherae and its herbicidal activity are reported here for the first time.     

Chemical constituents and antioxidant and biological activities of the essential oil from leaves of Solanum spirale

The essential oil of the leaves Solanium spirale Roxb. was isolated by hydrodistillation and analyzed for the first time using GC and GC-MS. Thirty-nine constituents were identified, constituting 73.36% of the total chromatographical oil components. (E)-Phytol (48.10%), n-hexadecanoic acid (7.34%), beta-selinene (3.67%), alpha-selinene (2.74%), octadecanoic acid (2.12%) and hexahydrofarnesyl acetone (2.00%) were the major components of this oil. The antioxidant activity of the essential oil was evaluated by using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. The oil exhibited week antioxidant activity with an IC50 of 41.89 mg/mL. The essential oil showed significant antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with MIC values of 43.0 microg/mL and 21.5 microg/mL, respectively. It also showed significant cytotoxicity against KB (oral cancer), MCF-7 (breast cancer) and NCI-H187 (small cell lung cancer) with the IC50 values of 26.42, 19.69, and 24.02 microg/mL, respectively.     

微量热法研究蟾蜍甾二烯类化合物对嗜热四膜虫BF5生长代谢的影响

采用微量热法研究中药蟾蜍中4种蟾蜍甾二烯类化合物(BD)对嗜热四膜虫BF5生长代谢的影响.在不同给药条件下,以表达热功率-时间曲线(热谱曲线)的特征参数生长速率常数(k),最大产热功率(Pmax)和半数抑制浓度(IC50)为指标,对4种蟾蜍甾二烯类化合物干预嗜热四膜虫生长代谢程度进行客观的量化评价.结果表明:k和Pmax均随4种蟾蜍甾二烯类化合物浓度的增加而相应减小,且k与不同化合物的相应浓度间有良好的线性关系(r0.98);华蟾毒精、蟾毒灵、蟾毒它灵和日蟾毒它灵的IC50分别为119.2、106.14、73.80和54.75μg·mL-1,即毒性效应大小顺序为日蟾毒它灵蟾毒它灵蟾毒灵华蟾毒精.初步构毒关系研究表明,在蟾蜍甾二烯结构母核C11上引入α-OH,C14上引入β-OH,C16上引入β-OAC以及C14与C15未发生脱水均可明显增加蟾蜍甾二烯对嗜热四膜虫BF5的毒性作用.     

Antibacterial and antifungal screening of Centaurium pulchellum crude extracts and main secoiridoid compounds

The main principles of C. pulchellum (Sw.) Druce, secoiridoid glycosides, have been studied as potent bioactive compounds. Here we scored their content in extracts of ten populations of this species. Antibacterial and antifungal assays of the extracts and pure secoiridoid glycosides were performed against eight bacterial strains and five fungal species. Methanol extracts from both aerial parts and roots exhibited excellent antibacterial (0.05-0.2 mg mL(-1)) and very good antifungal (0.1-2 mg mL(-1)) activity. Pure secoiridoid glycosides isolated from these extracts demonstrated very strong antibacterial (0.01-0.04 mg mL(-1)) and especially antifungal (0.001-0.1 mg mL(-1)) activity.     

Investigation of the Effect of Four Organic Acids in Radix Isatidis on E. coli Growth by Microcalorimetry

The inhibitory effects of four organic acids (OAs) in Radix Isatidis, a traditional Chinese medicinal herb, on Escherichia coli (E. coli) growth were investigated by microcalorimetry. The power‐time curves of E. coli growth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k₁, k₂), half inhibitory ratio (IC₅₀), maximum heat output (P_max) and peak time (t_p). The values of k₁ and k₂ of E. coli growth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover, P_max was reduced and the value of t_p increased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC₅₀ of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring.     

Antibacterial activity of 15-deoxygoyazensolide isolated from the stems of Minasia alpestris (Asteraceae) against oral pathogens

This work reports the isolation of the sesquiterpene lactone 15-deoxygoyazensolide from the stems of Minasia alpestris and the evaluation of its antimicrobial activity against the following oral pathogens: Enterococcus faecalis, Streptococcus salivarius, Streptococcus sobrinus, Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, and Lactobacillus casei. Despite the cytotoxicity and genotoxicity of other sesquiterpene lactones of the furanoheliangolide-type, our results revealed that this compound exhibits low antibacterial activity against the evaluated oral pathogens; however, an interesting selectivity against E. faecalis (minimum inhibitory concentration [MIC]=40 μg mL(-1)) and S. sobrinus (MIC=60 μg mL(-1)) was observed.     

First isolation of sesquiterpenes and flavonoids from Zingiber spectabile and identification of zerumbone as the major cell growth inhibitory component

Nine sesquiterpenes and eight flavonoids were isolated from Zingiber spectabile for the first time. Structures were determined by spectroscopic methods. The major compound zerumbone (1) was found to be the most active (IC(50) 13 microg mL(-1)) in cell growth inhibitory assay against colon carcinoma SW480 cells.     

Essential oil composition, cytotoxic and antibacterial activities of five Etlingera species from Borneo

Essential oils obtained by hydrodistillation from the rhizomes of Etlingera pyramidosphaera (K. Schum.) R. M. Sm, E. megalocheilos (Griff.) A.D. Poulsen, comb. nov., E. coccinea (Blume) S. Sakai & Nagam, E. elatior (Jack) R. M. Sm, and E. brevilabrum (Valeton) R. M. Sm were analyzed by GCMS. The highest oil yield was obtained from E. pyramidosphaera (0.45%), followed by E. elatior (0.38%), E. coccinea (0.30%), E. brevilabrum (0.28%) and E. megalocheilos (0.25%). The major constituents of the essential oils were oxygenated monoterpenes, followed by sesquiterpenes, oxygenated sesquiterpenes, oxygenated diterpenes and diterpenes. The essential oils from E. pyramidosphaera and E. brevilabrum exhibited the best cytotoxicity against MCF 7 (LC50: 7.5 +/- 0.5 mg mL(-1)) and HL 60 (LC50: 5.0 mg mL(-1)), respectively. Strong inhibition was also observed for the essential oils of E. coccinea and E. megalocheilos against Staphylococcus aureus (MIC: 8.0 +/- 0.5 mg mL(-1), and 5.0 +/- 0.5 mg mL(-1)) and Streptococcus pyrogenes (MIC: 6.0 +/- 0.5 mg mL(-1) and 8.0 +/- 0.5 mg mL(-1)).     

Antimicrobial flavonoids from the twigs of Populus nigra x Populus deltoides

A bioassay-guided fractionation of the ethyl acetate extract from the twigs of the hybrid poplar 'Neva', Populus nigra L.?×?Populus deltoides Marsh, led to the isolation of three flavonoids, which were identified by means of spectrometric and physicochemical analysis as 5-hydroxy-7-methoxy-flavone (1), 5,7-dihydoxy-flavone (2) and 5,7-dihydroxy-flavonol (3). These compounds were further screened for their antimicrobial activity against plant pathogens, including three bacteria (Pseudomonas lachrymans, Ralstonia solanacearum and Xanthomonas vesicatoria) and one fungus (Magnaporthe oryzae). Compounds 2 and 3 showed significant antibacterial activity, with minimum inhibitory concentrations (MICs) ranging from 15 to 25?μg?mL(-1), and median inhibitory concentrations (IC(50) values) from 4 to 18?μg?mL(-1). The results obtained provide promising baseline information for the potential use of the extract and flavonoids from this plant as antimicrobial agents to help control plant diseases.     

Evaluation of the effects of Mitragyna speciosa alkaloid extract on cytochrome P450 enzymes using a high throughput assay

The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown to be a fast and cost-effective way to perform CYP inhibition studies. The results indicated that MSE has the most potent inhibitory effect on CYP3A4 and CYP2D6, with apparent half-maximal inhibitory concentration (IC(50)) values of 0.78 μg/mL and 0.636 μg/mL, respectively. In addition, moderate inhibition was observed for CYP1A2, with an IC(50) of 39 μg/mL, and weak inhibition was detected for CYP2C19. The IC(50) of CYP2C19 could not be determined, however, because inhibition was <50%. Competitive inhibition was found for the MSE-treated CYP2D6 inhibition assay, whereas non-competitive inhibition was shown in inhibition assays using CYP3A4, CYP1A2 and CYP2C19. Quinidine (CYP2D6), ketoconazole (CYP3A4), tranylcypromine (CYP2C19) and furafylline (CYP1A2) were ACCESSused as positive controls throughout the experiments. This study shows that MSE may contribute to an herb-drug interaction if administered concomitantly with drugs that are substrates for CYP3A4, CYP2D6 and CYP1A2.     

Antioxidant and anticancer activity of fresh corm extract from Romulea tempskyana (Iridaceae)

The antioxidant and anticancer properties of a medicinal plant, Romulea tempskyana (R. tempskyana) (Iridaceae) were investigated. The fresh corm water extract of R. tempskyana significantly increased cell viability against H(2)O(2) cytotoxicity(.) The extract also showed high inhibition of the lipid peroxidation activity (78.20%), reducing power (IC(50) 64.99?μg?mL(-1)) activity and hydroxyl (IC(50) 38.66?μg?mL(-1)), superoxide (IC(50) 25.99?μg?ml(-1)) and DPPH (IC(50) 19.88?μg?mL(-1)) radical scavenging activity. On the other hand, treatment of the cells with higher extract concentration showed the anticancer activity inducing cytotoxicity. The extract significantly affected Hepatoma G2 and H1299 cell proliferation (IC(50); 103.79 and 88.15?μg?mL(-1)). The amount of MDA (2-fold and 2.5-fold) and activities of several cellular antioxidant enzymes, including Se-GSPx (30%, 15%), non-Se-GSH-Px (11%, 16%) and GST (17%, 23%) increased in Hepatoma G2 and H1299 cells treated with IC(50) concentrations of extract, respectively. These findings suggest that R. tempskyana extract exhibits antioxidant and carcinogenesis-reducing potential.