Antimicrobial antioxidant daucane sesquiterpenes from Ferula hermonis Boiss

Seventeen daucane sesquiterpenoid esters, including a new one (4), were isolated from the root of Ferula hermonis Boiss. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidence and correlated with known compounds. The relative stereochemistry of the new compound was determined using 2D NOESY and the most stable and the lowest energy conformation was determined using molecular modelling. The antimicrobial activity was evaluated by determination of MIC using the broth microdilution method against six bacterial strains and one fungal strain (Pseudomonas aeruginosa PAO1, Escherichia coli, Bacillus subtilis ATCC6633, Mycobacterium bovis BCG Pasteur, Mycobacterium tuberculosis H37Rv, Staphylococcus aureus ATCC6538 and Candida albicans SC5314). There was a significant indication that compounds 15, 16, 17 demonstrated potent activity against Gram +ve (S. aureus, B. subtilis), as well as Mycobacterium strains M. bovis BCG and M. tuberculosis H37Rv. None of the isolated compounds exhibited a significant antifungal activity. In the antioxidant study using the DPPH assay method, the highest radical scavenging activity was observed for compounds 15, 16, 17.     

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.     

Anti‐MRSA activity of oxysporone and xylitol from the endophytic fungus Pestalotia sp. growing on the Sundarbans mangrove plant Heritiera fomes

Heritiera fomes Buch.‐Ham., a mangrove plant from the Sundarbans, has adapted to a unique habitat, muddy saline water, anaerobic soil, brackish tidal activities, and high microbial competition. Endophytic fungal association protects this plant from adverse environmental conditions. This plant is used in Bangladeshi folk medicine, but it has not been extensively studied phytochemically, and there is hardly any report on investigation on endophytic fungi growing on this plant. In this study, endophytic fungi were isolated from the surface sterilized cladodes and leaves of H. fomes. The antimicrobial activities were evaluated against two Gram‐positive and two Gram‐negative bacteria and the fungal strain, Candida albicans. Extracts of Pestalotia sp. showed activities against all test bacterial strains, except that the ethyl acetate extract was inactive against Escherichia coli. The structures of the purified compounds, oxysporone and xylitol, were elucidated by spectroscopic means. The anti‐MRSA potential of the isolated compounds were determined against various MRSA strains, that is, ATCC 25923, SA‐1199B, RN4220, XU212, EMRSA‐15, and EMRSA‐16, with minimum inhibitory concentration values ranging from 32 to 128 μg/ml. This paper, for the first time, reports on the anti‐MRSA property of oxysporone and xylitol, isolation of the endophyte Pestalotia sp. from H. fomes, and isolation of xylitol from a Pestalotia sp.     

Characterisation of Antimicrobial Extracts from Dandelion Root (Taraxacum officinale) Using LC‐SPE‐NMR

Plant extracts have traditionally been used as sources of natural antimicrobial compounds, although in many cases, the compounds responsible for their antimicrobial efficacy have not been identified. In this study, crude and dialysed extracts from dandelion root (Taraxacum officinale) were evaluated for their antimicrobial properties against Gram positive and Gram negative bacterial strains. The methanol hydrophobic crude extract (DRE3) demonstrated the strongest inhibition of microbial growth against Staphylococcus aureus, methicillin‐resistant S. aureus and Bacillus cereus strains. Normal phase (NP) fractionation of DRE3 resulted in two fractions (NPF4 and NPF5) with enhanced antimicrobial activity. Further NP fractionation of NPF4 resulted in two fractions (NPF403 and NPF406) with increased antimicrobial activity. Further isolation and characterisation of compounds in NPF406 using liquid chromatography solid phase extraction nuclear magnetic resonance LC‐SPE‐NMR resulted in the identification of 9‐hydroxyoctadecatrienoic acid and 9‐hydroxyoctadecadienoic acid, while the phenolic compounds vanillin, coniferaldehyde and p‐methoxyphenylglyoxylic acid were also identified respectively. The molecular mass of these compounds was confirmed by LC mass spectroscopy (MS)/MS. In summary, the antimicrobial efficacy of dandelion root extracts demonstrated in this study support the use of dandelion root as a source of natural antimicrobial compounds. Copyright © 2015 John Wiley & Sons, Ltd.     

Chemical composition and biological activity of a new type of Brazilian propolis: Red propolis

Propolis has been used as a medicinal agent to treat infections and promote wound healing for centuries. The aim of the present study was to test the antimicrobial, antioxidant, and cytotoxic activities of a new type of Brazilian propolis, popularly called red propolis, as well as to analyze its chemical composition. The antimicrobial activity against Staphylococcus aureus ATCC 25923 and Staphylococcus mutans UA159 was evaluated and the chloroform fraction (Chlo-fr) was the most active with lower MIC ranging from 25 to 50 μg/ml. The hexane fraction (H-fr), having the highest concentration of total flavonoids, showed the best sequestrating activity for the free radical DPPH. The ethanolic extract of propolis (EEP) showed cytotoxic activity for the HeLa tumor cells with an IC₅₀ of 7.45 μg/ml. When the EEP was analyzed by GC–MS, seven new compounds were found, among which four were isoflavones. Our results showed that the red propolis has biologically active compounds that had never been reported in other types of Brazilian propolis.     

Antimicrobial activity of Acacia mellifera extracts and lupane triterpenes

Ethnopharmacological relevance

Acacia mellifera (Vahl) Benth (Leguminosae) is a subtropical medicinal plant that is widely used in traditional African medicines against various diseases such as pneumonia and malaria.

Aim of the study

The present study was performed to evaluate the antimicrobial effects of extracts from the stem bark of Acacia mellifera.

Materials and methods

The extracts were examined for antibacterial and antifungal activity using the disc-diffusion method against bacterial strains: Streptococcus pneumoniae (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 35218), Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) and fungal strains Candida albicans (ATCC 90028), Candida krusei (ATCC 6255), Cryptococcus neoformans (ATCC 6603) and clinical isolates of Microsporum gypseum and Trichophyton mentagrophytes.

Results

Some of these extracts were found to be active against some bacterial and fungal strains and were further fractionated to give 12 pure compounds. The methanolic and methanol:dichloromethane (1:1) extracts exhibited antibacterial and antifungal activity. The two were active against Staphylococcus aureus (ATCC 25923), Microsporum gypseum, and Trichophyton mentagrophytes. Activity guided fractionation led to isolation of two active compounds: 3-(Z)-cis coumaroylbetulin and 30-hydroxylup-20 (29)-en-3β-ol which were against Staphylococcus aureus (ATCC 25923), Microsporum gypseum, Trichophyton mentagrophytes and Pseudomonas aeruginosa (ATCC 27853).

Conclusions

These results may partly explain and support the use of Acacia mellifera stem barks for the treatment of infectious diseases in traditional Kenya medicine.     

In vitro Combinatory Antimicrobial Effect of Plumbagin with Oxacillin and Tetracycline against Staphylococcus aureus

Plumbagin (5‐hydroxy‐2‐methyl‐1,4‐naphthoquinone), a bicyclic naphthoquinone naturally distributed among Plumbago species, has been reported to have antimicrobial activity against a wide range of microorganisms. In this study, plumbagin was examined for its combinatory antimicrobial effect with tetracycline or oxacillin against nine strains of Staphylococcus aureus, including its methicillin‐ and multidrug‐resistant strains. Minimum inhibitory concentrations were determined through the broth microdilution method, whereas the combinatory effect was evaluated according to the sum of fractional inhibitory concentration (ΣFIC) indices. Additive interactions were obtained for both combinations against most of the strains tested. Synergy was obtained for combination with oxacillin against two out of seven strains (ΣFIC range 0.273–0.281), both were methicillin resistant. Our results proved plumbagin as a compound suitable for anti‐Staphylococcal combinatory testing. Moreover, to the best of our knowledge, this is the first report of plumbagin synergy with oxacillin against S. aureus strains, including its resistant forms. Copyright © 2014 John Wiley & Sons, Ltd.     

Anti‐leishmanial Activities of Extracts and Isolated Compounds from Drechslera rostrata and Eurotium tonpholium

The fungal extract of Drechslera rostrata and Eurotium tonpholium showed a significant anti‐leishmanial activity against Leishmania major; IC₅₀ was 28.8 and 28.2 μg/mL, respectively. Seven compounds, five from D. rostrata (H1–H5) and two from E. tonpholium (H6 and H7), were isolated and identified using different spectroscopic analysis including ¹HNMR, ¹³CNMR, Hetero‐nuclear multiple bond connectivity (HMBC), Hetero‐nuclear Multiple Quantum Correlation (HMQC), and EI‐MS. The isolated compounds are: di‐2‐ethylhexyl phthalate (1), (22E)‐5α,8α‐epidioxyergosta‐6,22‐diene‐3β‐ol (2),1,3,8‐trihydroxy‐6‐methyl‐nthraquinone (3), aloe‐emodine 8‐O‐glucopyranoside(4), 2R, 3R,4R,5R hexane 1, 2, 3, 4, 5, 6 hexole (Mannitol) (5), 1,8‐dihydroxy‐3‐methoxy‐6‐methyl‐anthraquinone (6) and 1, 4, 5‐trihydroxy‐7‐methoxy‐2‐methyl‐anthraquinone (7). However, compounds (1) and (6) showed activity against L. major with IC₅₀ of 3.2 and 10.38 µg/mL, respectively. On the other hand, oral administration of the two extracts (100 mg/kg) and compounds 1 and 6 (50 mg/kg) showed very good activity when compared with the anti‐leishmanial drug Pentostam (125 mg/kg). Interestingly, the complete heeling activity of the extracts and compounds (1) and (6) was obtained after 13–17 days of treatment, while complete healing activity of Pentostam was obtained after 28 days. No alteration on liver and kidney functions was recorded on animals treated with the two extracts for 15 consecutive days. Copyright © 2013 John Wiley & Sons, Ltd.     

Pimarane‐type Diterpenes Obtained by Biotransformation: Antimicrobial Properties Against Clinically Isolated Gram‐positive Multidrug‐resistant Bacteria

The present study describes the antimicrobial activity of five pimarane‐type diterpenes obtained by fungal biotransformation against several nosocomial multidrug‐resistant bacteria. Among the investigated metabolites, ent‐8(14),15‐pimaradien‐3β‐ol was the most active compound, with very promising minimal inhibitory concentration values (between 8.0 and 25.0 µg mL^?1). Time‐kill assays using this metabolite against Staphylococcus aureus (HCRP180) revealed that this compound exerted its bactericidal effect within 24 h at all the evaluated concentrations (8.0, 16.0, and 24.0 µg mL^?1). When this metabolite was associated with vancomycin at their minimal bactericidal concentration values, the resulting combination was able to drastically reduce the number of viable strains of S. aureus within the first 6 h, compared with these chemicals alone. The checkerboard assays conducted against this microorganism did not evidence any synergistic effects when this same combination was employed. In conclusion, our results point out that ent‐8(14),15‐pimaradien‐3β‐ol is an important metabolite in the search for new effective antimicrobial agents. Copyright © 2012 John Wiley & Sons, Ltd.     

灯盏细辛的抗氧化活性研究

目的:研究灯盏细辛6个化合物的抗氧化活性.方法:以灯盏细辛为原料,采用有机溶剂提取法和色谱柱法对灯盏细辛中化学成分进行提取与分离,利用核磁共振等波谱学方法进行结构鉴定,体外法检测6个化合物对1-二苯基-2-苦味酰肼自由基清除法( DPPH),2,2′-联氨-双-(3-乙基苯并噻唑啉-6-磺酸)自由基清除法(ABTS),O2·自由基和·OH自由基的清除能力,并以维生素C(Vc)为阳性对照,结果:6个化合物者对DPPH,ABTS,O-2·,·OH自由基均具有清除作用,且与浓度呈良好的量效关系,6个化合物清除自由基能力与Vc相似.结论:灯盏细辛中的6个化合物均具有较强的抗氧化活性.     

Antioxidant activity of yellow dock (Rumex crispus L., Polygonaceae) fruit extract

The methanol extract of ripe Rumex crispus L. fruits was evaluated for its antioxidant potential by assays for ferric‐reducing antioxidant power (FRAP), DPPH‐free radical scavenging activity (DPPH) and the influence on lipid peroxidation in liposomes (LP). Considerable activity was observed in all test systems (FRAP: 9.9 mmol Fe²⁺/g; DPPH IC₅₀: 3.7 μg/mL; LP IC₅₀: 4.9 μg/mL), comparable to that of BHT (FRAP: 8.0 μg/mL; DPPH IC₅₀: 19.4 μg/mL; LP IC₅₀: 3.5 μg/mL), but lower than the activity of ascorbic acid, rutin and quercetin, used as positive control substances. The in vivo effects were evaluated in several hepatic antioxidant systems (activities of LPx, GSH‐Px, Px, CAT and XOD, as well as GSH content), after treatment with the studied yellow dock extract in different doses, or in combination with carbon tetrachloride (CCl₄). Pretreatment with the R. crispus extract inhibited CCl₄‐induced oxidative stress by decreasing LPx and increasing GSH content in a dose dependent manner, bringing the levels of antioxidant enzymes to near control values. Copyright © 2010 John Wiley & Sons, Ltd.     

Bioavailability of Bioactive Molecules from Olive Leaf Extracts and its Functional Value

Olive leaves are an important low‐cost source of bioactive compounds. The present study aimed to examine the effect of in vitro digestibility of an olive leaf aqueous extract so as to prove the availability of its phenolic compounds as well as its antioxidant, antimicrobial, and anticancer activity after a simulated digestion process. The total phenolic content was significantly higher in the pure lyophilized extract. Phenolic compounds, however, decreased by 60% and 90% in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), respectively. Regarding antioxidant activity, it was reduced by 10% and 50% after gastric and intestinal digestion, respectively; despite this fact, high antioxidant capacity was found in both SGF and SIF. Moreover, the olive leaf extract showed an unusual combined antimicrobial action at low concentration, which suggested their great potential as nutraceuticals, particularly as a source of phenolic compounds. Finally, olive leaf extracts produced a general dose‐dependent cytotoxic effect against U937 cells. To sum up, these findings suggest that the olive leaf aqueous extract maintains its beneficial properties after a simulated digestion process, and therefore its regular consumption could be helpful in the management and the prevention of oxidative stress‐related chronic disease, bacterial infection, or even cancer. Copyright © 2016 John Wiley & Sons, Ltd.     

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.     

Antiplasmodial and cytotoxic activity of khellactone derivatives from Angelica purpuraefolia chung

The methanolic extract of the rhizomes parts of Agelica purpuraefolia was investigated for its activity against chloroquine‐sensitive strains of Plasmodium falciparum using the parasite lactate dehydrogenase assay method. Two natural khellactone, (+)‐4′‐Decanoyl‐cis‐khellactone (1) and (+)‐3′‐Decanoyl‐cis‐khellactone (2) were isolated from the rhizomes parts of A. purpuraefolia. Two compounds were evaluated for in vitro antiplasmodial activities as well as their cytotoxic potential on SK‐OV‐3 cancer cell line cells. Compounds 1, 2 showed notable growth inhibitory activity against chloroquine‐sensitive strains of Plasmodium falciparum with IC₅₀ values from 1.5 and 2.4 μM. This compound showed no significant cytotoxicity (IC₅₀ > 100 μM) evaluated using SK‐OV‐3 cancer cell line cells. This is the first report on the antiplasmodial activity of the compounds from A. purpuraefolia. Copyright © 2009 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.     

Antimicrobial,anti-inflammatory,anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil

The root of Carlina acanthifolia All. (Asteraceae) has been traditionally used in the treatment of various disorders including stomach and skin diseases. We studied antimicrobial, anti-inflammatory, anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil, in order to validate some of the ethnopharmacological claims. Antimicrobial activity was tested on 15 bacteria and three strains of fungi using the agar diffusion and broth microdilution methods. In assessing anti-inflammatory activity the carrageenan-induced rat paw oedema test was used, while ethanol-induced stress gastric ulcer test in rats was used in testing anti-ulcer activity. Antioxidant properties were evaluated trough the effect of the essential oil on lipid peroxidation (TBA assay) and its capability of quenching 2,2-diphenyl-1-picrylhydrazyl (DPPH) and OH radicals. The oil expressed significant antimicrobial activity, being the most active against Gram (+) bacteria: Streptococcus pyogenes, Enterococcus faecalis, Bacillus subtilis and against Candida albicans. In all applied concentrations, Carlina acanthifolia root essential oil reduced carrageenan-induced rat paw oedema in dose-dependent manner, achieving high degree of anti-inflammatory activity. The effect was comparable with that of indomethacin used as a reference drug. In the ethanol-induced stress gastric ulcer test in rats, it was shown that the tested essential oil produced significant dose-dependent gastroprotective activity. The results also pointed out substantial and dose-dependent antioxidant activity of the investigated essential oil, with carlina oxide as the main antioxidant component.     

贵州白苞蒿抗肿瘤、抗氧化内生真菌的筛选与鉴定

白苞蒿Artemisia lactiflora是一种重要的药用植物。对已分离获得的54株白苞蒿内生真菌粗提物分别采用MTT法和DPPH法进行体外抗肿瘤和抗氧化活性筛选,并采用分子生物学方法对筛选出的活性内生真菌进行鉴定。结果显示,共计10株（18.5%）白苞蒿内生真菌粗提物对人骨髓白血病细胞系（HL-60）、人乳腺癌细胞系（MCF-7）和人前列腺癌细胞系（PC-3）生长的抑制活性较好,其中以链格孢属GYBH47菌株粗提物的抗肿瘤活性最佳,对3种肿瘤细胞株的生长均有抑制作用;共计2株（3.7%）白苞蒿内生真菌粗提物的抗氧化活性较好,其中,拟茎点霉属GYBH42菌株粗提物同时具有抗氧化活性和细胞毒活性。表明贵州白苞蒿内生真菌是寻找有价值的生物活性成分的潜在资源,其生物活性成分值得进一步研究和开发。     

Isolation and characterization of a new hispolone derivative from antioxidant extracts of Pistacia atlantica

The quantification of the total phenolic compounds of Pistacia atlantica showed that the different parts of the tree are rich in natural phenolic compounds. The antioxidant tests proved that the phenolic extracts have a strong antioxidant activity. The positive correlation between the Trolox equivalent antioxidant capacity (TEAC) and the amount of phenolic compounds confirms their contribution to the antioxidant activity. Among the various phenolic compounds isolated and characterized by spectroscopic methods, a new natural antioxidant 1 (methyl 5‐(3,4‐dihydroxyphenyl)‐3‐hydroxypenta‐2,4‐dienoate) derived from hispolone 2 has been isolated from the mushroom Inonotus hispidus growing on Pistacia atlantica. Hispolone 2 (6‐(3,4‐dihydroxyphenyl)‐4‐hydroxyhexa‐3,5‐dien‐2‐one) and hispidin 3 (6‐(2‐(3,4‐dihydroxyphenyl)vinyl)‐4‐hydroxy‐2H‐pyran‐2‐one) have been also identified using spectroscopic methods, including 2D‐NMR and EI‐MS. Copyright © 2009 John Wiley & Sons, Ltd.     

Antimicrobial,antioxidant and anti‐inflammatory activity of young shoots of the smoke tree,Cotinus coggygria Scop

In this study, we investigated the antimicrobial activity of the young shoots of the smoke tree, Cotinus coggygria Scop., Anacardiaceae. The acetone extract and the derived ethyl acetate fraction effectively inhibited the growth of Gram‐positive and Gram‐negative bacteria (MIC 25–200 µg/ml), while the chloroform fraction showed pronounced activity against the yeast Candida albicans (MIC 3.12 µg/ml). The ethyl acetate fraction exhibited a significant ferric‐reducing ability (10.7 mmol Fe²⁺/g extract), a very high DPPH radical scavenging activity (SC₅₀ = 1.7 µg/ml) and inhibition of lipid peroxidation (IC₅₀ = 41.8 µg/ml). High amounts of total phenolics (929.8 mg/g), tannins (833.8 mg/g) and flavonoids (35.5 mg/g) were determined in the ethyl acetate fraction, which also exerted significant anti‐inflammatory (76.7%) and cytotoxic effects (IC₅₀ = 15.6 µg/ml). Copyright © 2012 John Wiley & Sons, Ltd.