Phytochemical analysis and antimicrobial activity of Cardaria draba (L.) Desv. volatiles

Two different volatile isolates from the aerial parts of Cardaria draba (L.) Desv., obtained either by hydrodistillation (Extract I) or by CH₂Cl₂ extraction subsequent to hydrolysis by exogenous myrosinase (Extract II), were characterized by GC‐FID and GC/MS analyses. The main volatiles obtained by hydrodistillation, i.e., 4‐(methylsulfanyl)butyl isothiocyanate ( 1 ; 28.0%) and 5‐(methylsulfanyl)pentanenitrile ( 2 ; 13.8%), originated from the degradation of glucoerucin. In Extract I, also volatiles without sulfur and/or nitrogen were identified. These were mostly hexadecanoic acid (10.8%), phytol (10.2%), dibutyl phthalate (4.5%), and some other compounds in smaller percentages. Extract II contained mostly glucosinolate degradation products. They originated from glucoraphanin, viz., 4‐(methylsulfinyl)butyl isothiocyanate ( 3 ; 69.2%) and 5‐(methylsulfinyl)pentanenitrile ( 4 ; 4.5%), glucosinalbin, viz., 2‐(4‐hydroxyphenyl)acetonitrile ( 5 ; 7.2%), and glucoerysolin, viz., 4‐(methylsulfonyl)butyl isothiocyanate ( 6 ; 5.0%). Moreover, the volatile samples were evaluated for their antimicrobial activity using the disc‐diffusion method and determining minimum inhibitory concentrations (MIC). All volatile isolates expressed a wide range of growth inhibition activity against both Gram‐positive and Gram‐negative bacteria and fungi. The MIC values varied between 4 and 128 μg/ml.     

Hedge Mustard (Sisymbrium officinale): Chemical Diversity of Volatiles and Their Antimicrobial Activity

Volatile compounds of hedge mustard (Sysimbrium officinale) have been investigated for the first time. Forthy‐two compounds were identified after hydrodistillation (without or upon autolysis) after gas chromatography and gas chromatography/mass spectrometry analyses. In addition, after decoction and hydrolysis of O‐glycosides, 18 volatile O‐aglycones were identified. In general, the main volatiles found in hydrodistillates were: isopropyl isothiocyanate (27.6–48.9%), 2‐methylpropanenitrile (0.5–18.8%), (Z)‐hex‐3‐en‐1‐ol (0.5–18.0%), sec‐butyl isothiocyanate (4.9–9.4%), (E)‐hex‐2‐enal (3.5–8.6%), (Z)‐hex‐2‐en‐1‐ol (0.3–8.4%), octanoic (0.5–8.6%) and dodecanoic acid (0–5.0%), 2‐methylbutanenitrile (0–4.6%), dibutyl phthalate (0–4.5%), and ethyl linolenate (0–3.6%). The main volatile O‐aglycones were: 2‐phenylethyl alcohol (21.5%), 6,7‐dehydro‐7,8‐dihydro‐3‐oxo‐α‐ionol (9.3%), eugenol (8.3%), benzyl alcohol (7.0%), ethyl vanillate (5.2%), 6‐(tert‐butyl)‐5‐methylphenol (5.1%), vanillin acetone (4.7%), ethyl 4‐hydroxybenzoate (4.3%), and 2‐hydroxy‐β‐ionone (3.8%). All hydrodistillates exhibited great potential of antibacterial activity against five Gram‐positive bacteria, nine ampicillin‐resistant Gram‐negative bacteria, and four fungi at a concentration of 500 μg/ml using the disc diffusion method.     

Glucosinolate changes in developing pods of single and double low varieties of autumn-sown oilseed rape (B. napus)

Single and double low varieties of oilseed rape were grown in the 1987/88 and 1988/89 seasons to study changes in the concentrations of total and individual glucosinolates within pods during development. Total glucosinolate concentration in seeds of all varieties increased during development when expressed on a fresh weight basis. The levels of the major alkenyl glucosinolates present in the seed; 2–hydroxy-3–butenyl, 3–butenyl and 4–pentenyl had been reduced in the transition from single to double low varieties. The major indole glucosinolates in the seed, 4–hydroxy-3–indolylmethyl and 3–indolylmethyl were present in the same amounts in single and double low varieties but in the latter represented a greater proportion of the total seed glucosinolate content. A decline in the total glucosinolate concentration in the pod walls with time together with the analogous profile of individual glucosinolates in the seeds and pod walls suggests that the pod wall is a major site of seed glucosinolate synthesis. Other plant parts may also have an important role to play in provision of intact glucosinolates or precursors to the pod walls for glucosinolate biosynthesis.     

Chemical composition and antimicrobial activity of the essential oil of Teucrium ramosissimum (Lamiaceae)

The phytochemical composition of the essential oil of Teucrium ramosissimum (aerial parts), harvested in a mountainous region of Tunisia, was analyzed. A total of 68 compounds, accounting for 99.44% of the essential oil, were identified by GC and GC/MS. The major compounds were beta-eudesmol (61; 44.52%), caryophyllene oxide (56; 9.35%), alpha-thujene (1; 5.51%), sabinene (4; 4.71%), and T-cadinol (59; 3.9%). The essential oil, which is being used in Tunisian folk medicine against infectious diseases, was tested for its antimicrobial properties against five different bacteria, and found to have weak to moderate activity, with minimal-inhibitory-concentration (MIC) and minimal-bactericidal-concentration (MBC) values in the range 0.24-0.36 and 1.3-2.9 mg/ml, resp.     

Anticancer activities of an antimicrobial peptide derivative of Ixosin-B amide

In nature, antimicrobial peptides (AMPs) represent the first line of defense against infection by pathogens; thus, they are generally good candidates for the development of antimicrobial agents. Recently, we reported two potent antimicrobial peptides, KWLRRVWRWWR-amide (MAP-04-03) and KRLRRVWRRWR-amide (MAP-04-04), which were derived from a fragment of Ixosin-B-amide (KSDVRRWRSRY). Since some cationic AMPs exhibited cytotoxic activity against cancer cells, in the current study, we further investigated the anticancer activity of these potent antimicrobial peptides by antiproliferative assays and wound-healing assays, and the effect of peptide on the cytoskeleton alteration and cell morphology were analyzed by confocal microscopy. Results indicated that MAP-04-03 not only exhibited inhibitory effects on the proliferation (IC₅₀ = 61.5 μM) and on the cell migration of MCF-7 breast cancer cells (at a concentration of 5 μM), but also affected the cytoskeleton at the concentration of 25 μM. These results demonstrated that MAP-04-03 can serve as a lead peptide analog for developing potent anticancer agents.     

In vitro antimicrobial activity of propolis and synergism between propolis and antimicrobial drugs

The aim of this study was to investigate antimicrobial properties of ethanolic extract of 13 propolis (EEP) samples from different regions of Serbia against 39 microorganisms (14 resistant or multiresistant to antibiotics), and to determine synergistic activity between antimicrobials and propolis. Antimicrobial activity of propolis samples was evaluated by agar diffusion and agar dilution method. The synergistic action of propolis with antimicrobial drugs was assayed by the disc diffusion method on agar containing subinhibitory concentrations of propolis. Obtained results indicate that EEP, irrespectively of microbial resistance to antibiotics, showed significant antimicrobial activities against Gram-positive bacteria (MIC 0.078%–1.25% of EEP) and yeasts (0.16%–1.25%), while Gram-negative bacteria were less susceptible (1.25&%ndash;>5%). Enterococcus faecalis was the most resistant Gram-positive bacterium, Salmonella spp. the most resistant Gram-negative bacteria, and Candida albicans the most resistant yeast. EEP showed synergism with selected antibiotics, and displayed ability to enhance the activities of antifungals. The shown antimicrobial potential of propolis alone or in combination with certain antibiotics and antifungals is of potential medical interest.     

Synthesis and antimicrobial activity of polyhalobenzonitrile quinazolin-4(3H)-one derivatives

A novel series of polyhalobenzonitrile quinazolin-4(3H)-one derivatives were synthesized and characterized by NMR, IR, MS, and HRMS spectra. All of the newly prepared compounds were screened for antimicrobial activities against four strains of bacteria (Gram-positive bacterial: Staphylococcus aureus and Bacillus cereus; Gram-negative bacterial: Escherichia coli and Pseudomonas aeruginosa) and one strain of fungi (Candida albicans). Among the synthesized compounds, 5-(dimethylamino)-8-(2,4,5-trichloro-isophthalonitrile) quinazolin-4(3H)-one (7k) exhibited significant activity towards Gram-positive bacterial, Gram-negative bacterial, and the fungi strains. The MIC (0.8–3.3 μg/mL) and MBC (2.6–7.8 μg/mL) for this compound were close to those of nofloxacin, chlorothalonil, and fluconazole, making it the most potent antimicrobial agents in the series.     

Synthesis and comparative study on the antimicrobial activity of hybrid materials based on silver nanoparticles (AgNps) stabilized by polyvinylpyrrolidone (PVP)

Hybrid materials based on polyvinylpyrrolidone (PVP) with silver nanoparticles (AgNps) were synthesized applying two different strategies based on thermal or chemical reduction of silver ions to silver nanoparticles using PVP as a stabilizer. The formation of spherical silver nanoparticles with diameter ranging from 9 to 16 nm was confirmed by TEM analysis. UV-vis and FTIR spectroscopy were also applied to confirm the successful formation of AgNps. The antibacterial activity of the synthesized AgNPs/PVP against etalon strains of three different groups of bacteria—Staphylococcus aureus (S. aureus; gram-positive bacteria), Escherichia coli (E. coli; gram-negative bacteria), Pseudomonas aeruginosa (P. aeruginosa; non-ferment gram-negative bacteria), as well as against spores of Bacillus subtilis (B. subtilis) was studied. AgNps/PVP were tested for the presence of fungicidal activity against different yeasts and mold such as Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Aspergillus brasiliensis. The hybrid materials showed a strong antimicrobial effect against the tested bacterial and fungal strains and therefore have potential applications in biotechnology and biomedical science.     

Glucosinolate spectrum of some AlgerianCruciferae

Seventeen glucosinolates were identified and quantified by micro-scale GC analysis in Algerian samples fromSisymbrieae, Arabideae, Lepidieae, andBrassiceae tribes of theCruciferae. Major glucosinolates and their amino acid precursors allowed species to fall naturally into tribes as classified byJanchen.     

Synthesis and antimicrobial activity of cysteine-free coprisin nonapeptides

Coprisin is a 43-mer defensin-like peptide from the dung beetle, Copris tripartitus. CopA3 (LLCIALRKK-NH₂), a 9-mer peptide containing a single free cysteine residue at position 3 of its sequence, was derived from the α-helical region of coprisin and exhibits potent antibacterial and anti-inflammatory activities. The single cysteine implies a tendency for dimerization; however, it remains unknown whether this cysteine residue is indispensible for CopA3’s antimicrobial activity. To address this issue, in the present study we synthesized eight cysteine-substituted monomeric CopA3 analogs and two dimeric analogs, CopA3 (Dimer) and CopIK (Dimer), and evaluated their antimicrobial effects against bacteria and fungi, as well as their hemolytic activity toward human erythrocytes. Under physiological conditions, CopA3 (Mono) exhibits a 6/4 (monomer/dimer) molar ratio in HPLC area percent, indicating that its effects on bacterial strains likely reflect a CopA3 (Mono)/CopA3 (Dimer) mixture. We also report the identification of CopW, a new cysteine-free nonapeptide derived from CopA3 that has potent antimicrobial activity with virtually no hemolytic activity. Apparently, the cysteine residue in CopA3 is not essential for its antimicrobial function. Notably, CopW also exhibited significant synergistic activity with ampicillin and showed more potent antifungal activity than either wild-type coprisin or melittin.     

Self-assembled synthesis, characterization and antimicrobial activity of zinc(II) salicylaldimine complexes

One-pot metal promoted reactions between salicylaldehyde and 4-methyl-1,3-phenylenediamine in the presence of metal salts acting as template agents yield zinc(II) salicylaldimine complexes containing N,N′-bis(salicylidene)-4-methyl-1,3-phenylenediamine (H₂L) as a result of the [2 + 1] Schiff base condensation. The complexes of formula [Zn(HL)Cl(H₂O)₂] · C₂H₅OH and [Zn(H₂L)₂Cl(NO₃)(H₂O)] · CH₃OH were characterized as powder solids and in solution by spectroscopic methods (IR, ¹H and ¹³C NMR, FAB-MS, ESI-MS, UV-Vis), thermogravimetric and elemental analysis, potentiometry, and tested for antimicrobial activity against Staphylococcusaureus in a minimum inhibitory concentration (MIC) experiment. In these two powder solid species, the salicylaldimine, formed in a self-assembly process, acts in two different coordination modes: as monodeprotonated bidentate chelator with an N,O donor set or as a neutral monodentate using exclusively oxygen as the donor atom without involving the nitrogen atoms in the coordination. However, crystals of these two complexes are isomorphous, with 1:2 metal:ligand stoichiometry, and display the latter, relatively rare coordination pattern. In solution, the presence of a 1:1 complex of monodeprotonated state is only detected. The complexes exhibit antimicrobial activity against S.aureus.     

Characterization and antimicrobial activity of the bioactive metabolites in streptomycete isolates

Twenty different streptomycete isolates were obtained from soils of southeast Serbia. Five isolates identified as Streptomyces hygroscopicus (SH100, SH101, SH102, SH103, and SH104) showed strong activity against Botrytis cinerea, a parasite found in domestic vines. These isolates were extensively studied for their in vitro antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeasts and fungi, and also antiviral activity against Herpes simplex. The results indicated that the obtained isolates were highly active against Botrytis cinerea, Candida albicans, and Herpes simplex, with an inhibition zone at ≥31 mm. The structure of the bioactive components was determined using elemental analysis, as well as UV/VIS, FTIR, and TLC.     

Palladium(II) complexes of quinolinylaminophosphonates: synthesis, structural characterization, antitumor and antimicrobial activity

Three types of palladium(II) halide complexes of quinolinylaminophosphonates have been synthesized and studied. Diethyl and dibutyl [α-anilino-(quinolin-2-ylmethyl)]phosphonates (L1, L2) act as N,N-chelate ligands through the quinoline and aniline nitrogens giving complexes cis-[Pd(L1/L2)X₂] (X═Cl, Br) (1-4). Their 3-substituted analogues [α-anilino-(quinolin-3-ylmethyl)]phosphonates (L3, L4) form dihalidopalladium complexes trans-[Pd(L3/L4)₂X₂] (5-8), with trans N-bonded ligand molecules only through the quinoline nitrogen. Dialkyl [α-(quinolin-3-ylamino)-N-benzyl]phosphonates (L5, L6) give tetrahalidodipalladium complexes [Pd₂(L5/L6)₃X₄] (9-12), containing one bridging and two terminal ligand molecules. The bridging molecule is bonded to the both palladium atoms, one through the quinoline and the other through the aminoquinoline nitrogen, whereas terminal ligand molecules are coordinated each only to one palladium via the quinoline nitrogen. Each palladium ion is also bonded to two halide ions in a trans square-planar fashion. The new complexes were identified and characterized by elemental analyses and by IR, UV-visible, ¹H, ¹³C and ³¹P nuclear magnetic resonance and ESI-mass spectroscopic studies. The crystal structures of complexes 1-4 and 6 were determined by X-ray structure analysis. The antitumor activity of complexes in vitro was investigated on several human tumor cell lines and the highest activity with cell growth inhibitory effects in the low micromolar range was observed for dipalladium complexes 11 and 12 derived from dibutyl ester L6. The antimicrobial properties in vitro of ligands and their complexes were studied using a wide spectrum of bacterial and fungal strains. No specific activity was noted. Only ligands L3 and L4 and tetrahalidodipalladium complexes 9 and 11 show poor activities against some Gram positive bacteria.     

Silver nanopaticles synthesized using the seed extract of Trigonella foenum-graecum L. and their antimicrobial mechanism and anticancer properties

Background

Synthesis of silver nanoparticles (AgNPs) through biological route plays an important role in their applications in the medical field, especially in the prevention of disease causing microbial pathogens and arresting the propagation of cancer cells. The stable, green synthesis of AgNPs is very much welcomed in the medical field because of their low toxicity. Therefore, the demands of AgNPs synthesised biologically is on the rise. The present study aimed to investigate the antimicrobial mechanisms and anticancer properties of the AgNPs synthesized using the seed extract of Trigonella foenum-graecum L. The AgNPs were characterized by UV–vis, SEM, XRD, FTIR and EDAX analysis. The minimum inhibitory concentrations (MIC) of the AgNPs were determined by the broth micro dilution method.

Glucosinolate responses of oilseed rape, mustard and kale to mechanical wounding and infestation by cabbage stem flea beetle (Psylliodes chrysocephala)

Mechanical wounding of the petioles of six laboratory-grown rapeseed ( Brassica napus ) cultivars induced physiological changes in the plant, markedly affecting the levels of individual glucosinolates. Greatest increases were observed for the indole glucosinolates, glucobrassicin and neoglucobrassicin. Such changes were usually associated with large decreases in the levels of aliphatic glucosinolates. The total glucosinolate content of the wounded plant was thus a reflection of these two opposing trends and wounding produced a greater relative indole glucosinolate content in this total figure. Thus increasing wounding was associated with an increase in indole glucosinolates and a decrease in aliphatic compounds.
Infestation of field- and laboratory-grown rapeseed with cabbage stem flea beetle ( Psylliodes chrysocephala ) produced similar effects, which were observed in various parts of the plant. Differences in response between field- and laboratory-grown infested plants are attributed to the different physiological ages of the harvested material.
Laboratory-grown kale and mustards also showed wound-induced glucosinolate changes. The kale, cv. Fribor, produced elevated levels of both indoles and aliphatics after wounding. Total glucosinolate content in the mustards, which, unlike rape and kale, normally contain only traces of indole glucosinolates in the unstressed state, was increased following wounding. This was, however, not associated with elevated levels of indole glucosinolates, but with accumulation of aliphatic ( Brassica nigra, B. juncea ) and aromatic ( Sinapis alba ) glucosinolates. The significance of these findings is discussed.     

Synthesis and antimicrobial evaluation of bile acid tridentate conjugates

Two series of novel bile acid tridentate conjugates with different linkers were synthesized and characterized, and their biological activities in vitro were evaluated. The procedure was straightforward and efficient to be carried out with high overall yield. The antimicrobial activity of the synthesized compounds against Saccharomyces cerevisiae, Aspergillus niger, Escherichia coli and Staphylococcus aureus was investigated in vitro. The best activity of minimal inhibitory concentrations (MICs) for 1c, 1c′, 2c and 2c′ against S. cerevisiae was up to 0.125 μg/mL.     

Tilapia (Oreochromis mossambicus) antimicrobial peptide, hepcidin 1-5, shows antitumor activity in cancer cells

The inhibitory function of tilapia hepcidin (TH)1-5, an antimicrobial peptide, was not examined in previous studies. In this study, we synthesized the TH1-5 peptide and tested TH1-5's antitumor activity against several tumor cell lines. We show that TH1-5 inhibited the proliferation of tumor cells and reduced colony formation in a soft agar assay. Scanning electron microscopy and transmission electron microscopy showed that TH1-5 altered the membrane structure similar to the function of a lytic peptide. Acridine orange/ethidium bromide staining, a wound-healing assay, and a flow cytometric analysis showed that TH1-5 induced necrosis with high-concentration treatment and induced apoptosis with low-concentration treatment. Inflammation is known to be closely associated with the development of cancer. TH1-5 showing anti-inflammatory effects in a previous publication induced us to evaluate the anti-inflammatory effects in cancer cell lines through the expressions of immune-related genes after being treated with the TH1-5 peptide. However, real-time qualitative RT-PCR indicated that TH1-5 treatment induced downregulation of the expressions of interleukin (IL)-6, IL-8, IL-12, IL-15, interferon-γ, CTSG, caspase-7, and Bcl-2, and upregulation of IL-2 and CAPN5 in HeLa cells, and upregulation of IL-8 and CTSG in HT1080 cells. These results suggest that TH1-5 possibly induces an inflammatory response in HeLa cells, but not in HT1080 cells. Overall, these results indicate that TH1-5 possesses the potential to be a novel peptide for cancer therapy.     

Xanthones from Garcinia smeathmannii (Oliver) and their antimicrobial activity

Two new xanthones, smeathxanthone A (1) (2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone) and smeathxanthone B (2) (5,7,10-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)[2H, 6H]pyrano[3,2-b]xanthen-6-one), have been isolated from the stem bark of Garcinia smeathmannii, and their structures elucidated on the basis of 1D and 2D NMR experiments. 1,3,5-Trihydroxyxanthone and 1,5-dihydroxyxanthone were also obtained. The compounds showed only modest activity against a range of bacteria and yeasts.     

Synthesis and antimicrobial activity of imidazole and pyridine appended cholestane-based conjugates

A series of 3α-amino-5α-cholestane and 3α,7α-diamino-5α-cholestane derivatives containing imidazole and pyridine rings were synthesized by simple and effective reductive amination, and their in vitro activities against a range of Gram-positive and Gram-negative strains were evaluated. Most of the compound exhibited enhanced activity against MRSA pathogen. 3α,7α-Di(pyridylmethyl)amino-5α-cholestane 10 showed the highest potency in these series toward the Gram-positive bacteria, Staphylococcus epidermidis 887E, with the lowest MIC value of 1 μg/mL.     

Synthesis and antimicrobial activity of some new hydrazone-bridged thiazole-pyrrole derivatives

In this work, we synthesized fourteen different compounds which contain hydrazone bridged thiazole and pyrrole rings. For this purpose, pyrrole-2-carboxaldehydes were reacted directly with thiosemicarbazide in ethanol and then obtained thiosemicarbazones were condensed with α-bromoacetophenone derivatives (Hantzsch reaction) to give 1-substituted pyrrole-2-carboxaldehyde [4-(4-substituted phenyl)-1,3-thiazol-2-yl] hydrazones. The structures of the obtained compounds were elucidated by using IR, ¹H-NMR and FAB⁺-MS spectral data and elemental analyses results. All of the compounds were screened for their antibacterial and antifungal activities against twelve different microorganisms by using microbroth dilution method. Ketoconazole and chloramphenicol were used as standard drugs. All of the compounds showed good activity against Staphylococcus aureus and Enterococcus faecalis.