Alpinia katsumadai Extracts Inhibit Adhesion and Invasion of Campylobacter jejuni in Animal and Human Foetal Small Intestine Cell Lines

Alpinia katsumadai is used in traditional Chinese medicine for abdominal distention, pain, and diarrhoea. Campylobacter jejuni is the most common cause of bacterial food‐borne diarrhoeal illnesses worldwide. Adhesion to gut epithelium is a prerequisite in its pathogenesis. The antimicrobial, cytotoxic, and anti‐adhesive activities of a chemically characterised extract (SEE) and its residual material of hydrodistillation (hdSEE‐R) from A. katsumadai seeds were evaluated against C. jejuni. Minimal inhibitory concentrations for SEE and hdSEE‐R were 0.5 mg/mL and 0.25 mg/mL, respectively, and there was no cytotoxic influence in the anti‐adhesion tests, as these were performed at much lower concentrations of these tested plant extracts. Adhesion of C. jejuni to pig (PSI) and human foetal (H4) small‐intestine cell lines was significantly decreased at lower concentrations (0.2 to 50 µg/mL). In the same concentration range, the invasiveness of C. jejuni in PSI cells was reduced by 45% to 65% when they were treated with SEE or hdSEE‐R. The hdSEE‐R represents a bioactive waste with a high phenolic content and an anti‐adhesive activity against C. jejuni and thus has the potential for use in pharmaceutical and food products. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of Cranberry Extracts on Growth and Biofilm Production of Escherichia coli and Staphylococcus species

Biofilm producing bacteria such as Staphylococcus species and Escherichia coli are the most common cause of catheter related urinary tract infections (UTIs). The American cranberry (Vaccinium macrocarpon) is utilized widely as a prophylaxis for UTIs due to its prevention of microbial adhesion. Cranberry contains proanthocyanidins (PACs), which have been implicated as active constituents responsible for its bacterial antiadhesive properties. Despite overwhelming data supporting cranberry's beneficial effects against human pathogenic bacteria, there is limited information regarding its effects on biofilm formation. This study evaluated the effects of three proprietary PAC‐standardized cranberry extracts on the inhibition of bacterial growth and biofilm production against a panel of clinically relevant pathogens: Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin‐resistant S. aureus (MRSA), Staphylococcus saprophyticus and Escherichia coli. The extracts inhibited the growth of the Gram‐positive bacteria (Staphylococcus spp.) but not the Gram‐negative species (E. coli) with minimum inhibitory concentrations in the range 0.02–5 mg/mL. The extracts also inhibited biofilm production by the Gram‐positive bacteria but did not eradicate their established biofilm. These results suggest that cranberry may have beneficial effects against the growth and biofilm producing capability of Gram‐positive bacteria pathogens. Copyright © 2012 John Wiley & Sons, Ltd.     

Inhibition of bacterial growth and biofilm production by constituents from Hypericum spp

Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific constituents responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericum ellipticum, Hypericum prolificum, and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin‐resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven compounds demonstrated growth inhibition against the Gram‐positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 µg/mL to 7.81 µg/mL. Four of the secondary metabolites inhibited biofilm production by certain Gram‐positive strains at sub‐MIC concentrations. Copyright © 2011 John Wiley & Sons, Ltd.     

In Vitro Antibacterial Activity and Synergistic Antibiotic Effects of Phlorotannins Isolated from Eisenia bicyclis Against Methicillin‐Resistant Staphylococcus aureus

Six phlorotannins, isolated from Eisenia bicyclis, were evaluated for antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) of the compounds were in the range 32 to 64 µg/mL. Phlorofucofuroeckol‐A (PFF) exhibited the highest anti‐MRSA activity, with an MIC of 32 µg/mL. An investigation of the interaction between these compounds and the β‐lactam antibiotics ampicillin, penicillin, and oxacillin revealed synergistic action against MRSA in combination with compound PFF. To our knowledge, this is the first report on the anti‐MRSA activity of phlorotannins from E. bicyclis. The results obtained in this study suggest that the compounds derived from E. bicyclis can be a good source of natural antibacterial agents against MRSA. Copyright © 2012 John Wiley & Sons, Ltd.     

Antimicrobial potential of Australian macrofungi extracts against foodborne and other pathogens

Basidiomycetous macrofungi have therapeutic potential due to antimicrobial activity but little information is available for Australian macrofungi. Therefore, the present study investigated 12 Australian basidiomycetous macrofungi, previously shown to have promising activity against Staphylococcus aureus and Escherichia coli, for their antimicrobial potential against a range of other clinically relevant micro‐organisms. Fruiting bodies were collected from across Queensland, Australia, freeze‐dried and sequentially extracted with water and ethanol. The crude extracts were tested at 10 mg/mL and 1 mg/mL against six pathogens including two Gram‐positive and two Gram‐negative bacteria along with two fungi using a high throughput 96‐well microplate bioassay. A degree of specificity in activity was exhibited by the water extract of Ramaria sp. (Gomphaceae) and the ethanol extracts of Psathyrella sp. (Psathyrellaceae) and Hohenbuehelia sp., which inhibited the growth of the two fungal pathogens used in the assay. Similarly, the ethanol extract of Fomitopsis lilacinogilva (Fomitopsidaceae) was active against the Gram‐positive bacteria B. cereus only. Activity against a wider range of the microorganisms used in the assay was exhibited by the ethanol extract of Ramaria sp. and the water extract of Hohenbuehelia sp. (Pleurotaceae). These macrofungi can serve as new sources for the discovery and development of much needed new antimicrobials. Copyright © 2011 John Wiley & Sons, Ltd.     

Catechin‐based Procyanidins from Peumus boldus Mol. Aqueous Extract Inhibit Helicobacter pylori Urease and Adherence to Adenocarcinoma Gastric Cells

In this work, the anti‐Helicobacter pylori effect of an aqueous extract from dried leaves of Peumus boldus Mol. (Monimiaceae) was evaluated. This extract displayed high inhibitory activity against H. pylori urease. Therefore, in order to clarify the type of substances responsible for such effect, a bioassay‐guided fractionation strategy was carried out. The active compounds in the fractions were characterized through different chromatographic methods (RP‐HPLC; HILIC‐HPLC). The fraction named F5 (mDP = 7.8) from aqueous extract was the most active against H. pylori urease with an IC₅₀ = 15.9 µg gallic acid equivalents (GAE)/mL. HPLC analysis evidenced that F5 was composed mainly by catechin‐derived proanthocyanidins (LC‐MS and phloroglucinolysis). The anti‐adherent effect of boldo was assessed by co‐culture of H. pylori and AGS cells. Both the aqueous extract and F5 showed an anti‐adherent effect in a concentration‐dependent manner. An 89.3% of inhibition was reached at 2.0 mg GAE/mL of boldo extract. In conjunction, our results suggest that boldo extract has a potent anti‐urease activity and anti‐adherent effect against H. pylori, properties directly linked with the presence of catechin‐derived proanthocyanidins. Copyright © 2014 John Wiley & Sons, Ltd.     

利用UPLC/Q-TOF-MS/MS主成分分析和T-test探讨生半夏与法半夏有毒成分的差异

目的：从化学成分探讨生半夏与法半夏的差异。方法：制备生半夏和法半夏样品并采用UPLC/Q-TOF-MS/MS测定,通过主成分分析(PCA)和T检验分析研究两组样品之间的差别,并确定相应的化学标记物。UPLC/Q-TOF-MS/MS可准确地测定得到荷质比和MS/MS 的碎片数据,通过参考文献或数据库对照相应数据我们可以鉴别相应化合物。结果：甘草苷、甘草素、溶血磷脂酰胆碱(LPC)是最具特征的化学标记物。由于LPC可导致炎症反应的发生,炮制前后LPC的减少是减毒的原因之一;甘草苷和甘草素有治疗炎症的作用且能减少肝损伤作用,其在炮制后的法半夏中的增加也是减毒的原因。结论：该方法不仅可探索传统中药炮制后减毒的机制还可分别对炮制前后中药的质量进行控制。     

In vitro Antimicrobial Activity of Royleanone Derivatives Against Gram‐Positive Bacterial Pathogens

Infections caused by multiresistant bacterial pathogens are a significant problem worldwide, turning the search for natural compounds to act as alternatives to antibiotics of major importance. The aim of the present study was to investigate the in vitro antimicrobial activity of 7α‐acetoxy‐6β‐hydroxyroyleanone (1), isolated from Plectranthus grandidentatus (Lamiaceae), and 11 additional royleanone abietane derivatives of 1 (2–12) against important Gram‐positive human bacterial pathogens. Results showed that the aromatic and alkylic esters 2, 3 and 5 are more active than 1 against Enterococcus and Staphylococcus (minimum inhibitory concentration (MIC) values ranging from 0.98 to 62.50 µg/mL). Moreover, 7α‐acetoxy‐6β‐hydroxy‐12‐O‐(4‐chloro)benzoylroyleanone (2) gave rise to a new antibacterial‐prototype (MIC values of 3.91–15.63 µg/mL against Staphylococcus and of 0.98–3.91 µg/mL against Enterococcus). The results showed that the compounds under analysis also present antimicrobial activity against resistant bacteria. The hydrophobic extra‐interactions with bacterial targets seem to play an important role on the activity of royleanones derivatives. Copyright © 2013 John Wiley & Sons, Ltd.     

Suppression of Propionibacterium acnes‐stimulated proinflammatory cytokines by Chinese bayberry extracts and its active constituent myricetin in human sebocytes in vitro

Myrica rubra Sieb. et Zucc. (Myricaceae), known as Chinese bayberry, is traditionally used as folk medicine in Asian countries. The interaction of Propionibacterium acnes signalling with sebocytes is considered important in the pathogenesis of acne. In the present study, extracts and active compounds of Chinese bayberry were used to determine chemical antioxidant activity and anti‐inflammatory effects in P. acnes‐stimulated human SZ95 sebocytes. A high‐performance liquid chromatography with electrochemical detection system was used to analyse the phenolic composition of bayberry extracts. Accordingly, the flavonols, myricitrin and myricetin, were found to be abundant in the unhydrolysed and hydrolysed extracts of Chinese bayberry fruits, respectively. The anthocyanin cyanidin‐3‐glucoside was also predominantly found in the unhydrolysed extracts. Quantification of human inflammatory cytokines indicated that cell‐free extracts of P. acnes stimulated IL‐8 and IL‐6 production, which was inhibited by myricetin, rather than its glycoside or anthocyanin. Myricetin also exhibited inhibitory effects in P. acnes‐stimulated gene expression of Toll‐like receptor (TLR) 2 and protein phosphorylation of p70 S6 kinase. In conclusion, myricetin shows a suppressive effect on P. acnes‐induced cytokine production through regulation of the TLR and mammalian target of rapamycin pathways. Myricetin goes beyond previous research findings to potentially modulate inflammatory signalling in human sebocytes. These results will be valuable in developing anti‐inflammatory agents against skin acne.     

鱼腥草素钠联合EDTA-Na2对生物被膜菌的影响

目的 探索鱼腥草素钠(SH)联合乙二胺四乙酸二钠(EDTA-Na₂)对生物被膜菌的影响,寻找潜在的抗生素替代品.方法 通过微量稀释法以及棋盘法,测定SH和EDTA-Na₂对铜绿假单胞菌(Pseudomonas aeruginosa,PA)、金黄色葡萄球菌(Staphylococcus aureus,SA)、白色念珠菌(Candida albicans,CA)的最小抑菌浓度(MIC)和最小膜清除浓度(MBEC)以及两药协同点;通过平板稀释涂布法测定3种菌在协同点的生存曲线;扫描电子显微镜法(SEM)观察PA、SA和CA生物被膜的形态.结果 SH对PA、SA和CA的MIC分别为2.048、0.064、0.064 mg/mL,MBEC分别为2.048、0.256、0.512 mg/mL;EDTA-Na₂对PA、SA和CA的MIC分别为3.75、0.938、0.117 mg/mL,MBEC分别为15、3.75、30 mg/mL;SH联合EDTA-Na₂(SH/EDTA-Na₂)对PA、SA和CA的MIC(mg/mL)分别为0.256/0.938、0.008/0.233、0.008/0.029,MBEC(mg/mL)分别为0.512/3.722、0.032/0.469、0.064/0.938;SEM观察到两药联合对细菌的生长抑制和生物被膜的清除有明显作用,载体上的细菌显著减少,未见或仅有少量的生物被膜结构,与空白对照组比较差异明显.结论 SH与EDTA-Na₂具有协同作用,二者联合能够显著增强SH对PA、SA和CA的生长抑制和生物被膜的清除作用.     

In vivo and in vitro antibacterial activity of acanthospermal B, a sesquiterpene lactone isolated from Acanthospermum hispidum

Acanthospermal B (AcB), the major sesquiterpene lactone (SL) of Acanthospermum hispidum, an herb widely spread in Argentina, is a selective antibacterial agent against Enterococcus faecalis and Staphylococcus aureus, but inactive on Gram‐negative and Lactobacillus. Methicillin‐resistant Staphylococcus aureus (MRSA) is one of the main microorganisms involved in human chronic infection. A balb\c mouse skin infection model was developed to reproduce the lesions caused by acute and chronic infections produced by MRSA. After determination of the maximum concentration of AcB unable to produce tissular injury after intradermal injection, the anti‐MRSA effect of AcB was evaluated on skin, liver and spleen tissues of infected mice. AcB, at doses of 2.5 mg/kg, produced a ten times decrease of MRSA growth in skin infection. In addition, the same dose prevented the dissemination to liver and/or spleen. AcB also displayed a bacteriostatic effect, in vitro, on MRSA cultures at 50 µg/mL that seems to be caused by partial denaturation of total bacterial DNA and/or inhibition of the PCR reaction in not denaturized DNA. Finally, total MRSA cell wall lysis occurred at a concentration of 100 µg/mL of AcB after 2 h of exposure. Copyright © 2010 John Wiley & Sons, Ltd.     

Anti‐Leishmanial,Anti‐Inflammatory and Antimicrobial Activities of Phenolic Derivatives from Tibouchina paratropica

A new phenolic derivative, 2,8‐dihydroxy‐7H‐furo[2,3‐f]chromen‐7‐one ( 1 ), together with isoquercitrin ( 2 ), was isolated from the aerial parts of Tibouchina paratropica. Compound structures were elucidated by spectroscopic methods. Both compounds show antimicrobial activit y towards a panel of bacterial and fungal pathogens, and compound 1 displayed potent anti‐parasitic activity against Leishmania donovani (IC₅₀ = 0.809 µg/mL). In addition, an 85% reduction in the secretion of the pro‐inflammatory cytokine IL‐6 was recorded when macrophages challenged with lipopolysaccharide were exposed to compound 1 , but no effect on the anti‐inflammatory IL‐10 was observed. Compound 2 showed neither anti‐parasitic nor anti‐inflammatory properties. In addition, no cytotoxic activities were observed against the human‐derived macrophage THP‐1 cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Two New Xanthones from Hypericum sampsonii and biological activity of the isolated compounds

Phytochemical investigation of the CH₂Cl₂ extract of the aerial part of Hypericum sampsonii yielded two new prenylated xanthones, hypericumxanthone A and B, together with three known xanthones. Their structures were elucidated by analysis of physical and spectral (UV, IR, mass and NMR) data and comparison of spectroscopic data with those reported previously. All these compounds were evaluated for in vitro antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). Two new compounds were also tested for their cytotoxicity against human breast (MCF‐7), hepatoma (HepG2), colon (HT‐29) and lung (A549) tumour cell lines. Two new compounds showed moderate antibacterial activities at minimum inhibitory concentrations (MIC) of 16 and 32 µg/mL, respectively, whereas the positive standard antibacterial drug, vancomycin, showed an MIC of 8 µg/mL. The other compounds were inactive against MRSA. In addition, hypericumxanthone B showed weak inhibitory activities against four human tumour cell lines. Copyright © 2010 John Wiley & Sons, Ltd.     

Flavonoids from Sophora moorcroftiana and their Synergistic Antibacterial Effects on MRSA

Synergy is now a widely recognized approach that has direct applicability for new pharmaceuticals. The ethanolic extract of the aerial parts of the herb Sophora moorcroftiana showed significant antibacterial activity against drug‐resistant Staphylococcus aureus, and its minimum inhibitory concentration (MIC) was 8 µg/mL. In a phytochemical study of the extract, five flavonoids were obtained. However, the isolates exhibited antibacterial activity in the range of 32–128 µg/mL, which was weaker than the extract. In combination with antibiotics, the antibacterially inactive compound genistein (1) and diosmetin (4) showed significant synergistic activity against drug‐resistant S. aureus. In combination with norfloxacin, genistein (1) reduced the MIC to 16 µg/mL and showed synergy against strain SA1199B with a fractional inhibitory concentration index (FICI) of 0.38. With the antibiotics norfloxacin, streptomycin and ciprofloxacin, diosmetin (4) showed synergy against SA1199B, RN4220 and EMRSA‐15, with FICI values of 0.38, 0.38 and 0.09, respectively. In an efflux experiment to elucidate a plausible mechanism for the observed synergy, genistein showed marginal inhibition of the NorA efflux protein. Copyright © 2013 John Wiley & Sons, Ltd.     

Quinolone Alkaloids from Fructus Euodiae Show Activity Against Methicillin‐Resistant Staphylococcus aureus

Fructus Euodiae is used in Traditional Chinese Medicine to treat infection. In this study, four of the quinolone alkaloids isolated from Fructus Euodiae showed activity against methicillin‐resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) were 8–128 µg/mL, which were equivalent to or lower than the control antibiotics, oxacillin, erythromycin and tetracycline (MIC ≥128 µg/mL). Among these isolated quinolone alkaloids, evocarpine with a 13 carbon alkenyl chain substituent at position‐2 showed the best activity against MRSA. This study has demonstrated the potential of quinolone alkaloids from Fructus Euodiae as anti‐MRSA compounds and supports the traditional use of the fruit as a treatment for bacterial infections. Copyright © 2013 John Wiley & Sons, Ltd.     

Antibacterial activity of the roots,stems and leaves of Alchornea floribunda

Ethnopharmacological relevance

Alchornea floribunda Müll. Arg. is used in traditional medicine across Africa for the treatment of bacterial, fungal, parasitic and inflammatory disorders.

Aim of the study

To evaluate the antibacterial activity of the crude extracts of different plant parts in order to provide a scientific rationale for the proposed broad efficacy of Alchornea floribunda in the treatment of bacterial infections.

Materials and methods

Extracts of roots, stems and leaves were prepared using solvents of various polarities in order to extract a wide range of phytochemicals. The antibacterial activity of these crude extracts was evaluated by micro-dilution assay, against Gram-positive (i.e. Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus and Staphylococcus saprophyticus) as well as Gram-negative (i.e. Escherichia coli, Klebsiella pneumoniae, Moraxella catarrhalis and Proteus mirabilis) bacteria.

Results

Generally, the ethanol (EtOH), methanol (MeOH), ethyl acetate (EtOAc) and chloroform (CHCl₃) extracts demonstrated the best activities, with the leaves exhibiting the highest average activity for six of the eight pathogens. Of these, the ethanolic leaf extract was the most active against Staphylococcus aureus with an MIC value of 50 µg/mL. Some other notable activity was observed for the ethyl acetate and chloroform root extracts against Staphylococcus aureus (50 µg/mL), and for selected stem extracts against Staphylococcus aureus (50 µg/mL), Klebsiella pneumoniae (63 µg/mL) and Staphylococcus saprophyticus (63 µg/mL).

Conclusion

This study demonstrates the promising antibacterial activity of Alchornea floribunda against both Gram-positive and Gram-negative bacteria responsible for gastrointestinal, skin, respiratory and urinary ailments, and validates its use in the ethnopharmacology of the region.     

Inhibition Activity of Wild Berry Juice Fractions against Streptococcus pneumoniae Binding to Human Bronchial Cells

Bacterial adhesion to the cell surface is a crucial step before infection can take place. Inhibition of bacterial binding offers a novel preventive approach against infections. Cranberry (Vaccinium macrocarpon Ait.) juice has been found to have antiadhesive activity against different bacteria. Streptococcus pneumoniae is an important pathogen and the most common cause for pneumonia, meningitis, and otitis media. In this study the inhibitory activity of cranberry (Vaccinium oxycoccos L.), bilberry (Vaccinium myrtillus L.) and crowberry (Empetrum nigrum and Empetrum hermaphroditum L.) juice fractions against pneumococcal binding was tested using human bronchial cells (Calu‐3) as an adhesion model. In addition, the antimicrobial activity of the berry juice fractions was tested. It was found that the studied berry juice fractions had antiadhesion activity and cranberry juice was the most active. The adhesion inhibition activity of cranberry juice was nearly 90% at a concentration of 8.7 mg/g of soluble solids. The antimicrobial activity of the studied berry juice fractions was found to be remarkable; pneumococcal growth was inhibited totally at a concentration of ～86 mg/g. Both antiadhesion and antimicrobial activities were reduced after solid‐phase extraction of the berry juices, which may suggest molecular synergistic effects of the berry juice molecules against S. pneumoniae. The findings indicate that cranberry, bilberry and crowberry juices have potential against pneumococcal infections.     

High Throughput Screening of Natural Products for Anti‐mitotic Effects in MDA‐MB‐231 Human Breast Carcinoma Cells

Some of the most effective anti‐mitotic microtubule‐binding agents, such as paclitaxel (Taxus brevifolia) were originally discovered through robust National Cancer Institute botanical screenings. In this study, a high‐through put microarray format was utilized to screen 897 aqueous extracts of commonly used natural products (0.00015–0.5 mg/mL) relative to paclitaxel for anti‐mitotic effects (independent of toxicity) on proliferation of MDA‐MB‐231 cells. The data obtained showed that less than 1.34 % of the extracts tested showed inhibitory growth (IG₅₀) properties <0.0183 mg/mL. The most potent anti‐mitotics (independent of toxicity) were Mandrake root (Podophyllum peltatum), Truja twigs (Thuja occidentalis), Colorado desert mistletoe (Phoradendron flavescens), Tou Gu Cao Speranskia herb (Speranskia tuberculata), Bentonite clay, Bunge root (Pulsatilla chinensis), Brucea fruit (Brucea javanica), Madder root (Rubia tinctorum), Gallnut of Chinese Sumac (Melaphis chinensis), Elecampane root (Inula Helenium), Yuan Zhi root (Polygala tenuifolia), Pagoda Tree fruit (Melia Toosendan), Stone root (Collinsonia Canadensis), and others such as American Witchhazel, Arjun, and Bladderwrack. The strongest tumoricidal herbs identified from amongst the subset evaluated for anti‐mitotic properties were wild yam (Dioscorea villosa), beth root (Trillium Pendulum), and alkanet root (Lithospermum canescens). Additional data was obtained on a lesser‐recognized herb: (S. tuberculata), which showed growth inhibition on BT‐474 (human ductal breast carcinoma) and Ishikawa (human endometrial adenocarcinoma) cells with ability to block replicative DNA synthesis, leading to G2 arrest in MDA‐MB‐231 cells. In conclusion, these findings present relative potency of anti‐mitotic natural plants that are effective against human breast carcinoma MDA‐MB‐231 cell division. Copyright © 2013 John Wiley & Sons, Ltd.