Antimicrobial Activities of Solanum aculeastrum Fruit Extract against Escherichia coli, Staphylococcus aureus and Candida albicans: Significance of African Traditional Medicine in Combating Infections and Attaining Universal Health Coverage

Solanum aculeastrum, a member of the Solanum genus, has a rich history of traditional use in various populations throughout tropical and southern Africa for treating different ailments. This study investigated the antimicrobial activities of S. aculeastrum fruit extracts grown in Zambia against Escherichia coli (E. coli) (ATCC 25922), Staphylococcus aureus (S. aureus) (ATCC 25923), and Candida albicans (C. albicans). After being dried in an oven at 50°C for eight days, the fruits of S. aculeastrum were pulverised and subjected to extraction using methanol and distilled water as solvents. The resulting crude extract was then filtered, concentrated using a water bath, and packed into airtight containers separately. The disc diffusion method was employed to evaluate the antimicrobial activity of the extracts. The results showed that both the methanolic and aqueous extracts demonstrated antimicrobial activity against S. aureus and C. albicans, but not against E. coli. The zone of inhibition was greater in S. aureus than in C. albicans. This study highlights the importance of researching plants for their medicinal properties, which can pave the way for discovering natural product-based drugs with potential antimicrobial properties. These findings recommend further studies on plants used in African traditional medicine.

Antimicrobial activities and analysis of the crude extract,fractions and compounds from the Lomatogonium rotatum

This study was evaluated the antimicrobial activities of the crude extract,different fractions,and compounds from the plant of Lomatogonium carinthiacum.The fractions of chloroform and compounds 5,2 and 6 exhibited stronger antimicrobial activities.Compound 5 was the most active while Staphylococcus aureus and Candida albicans were sensitive to all the tested compounds.The existence of a relationship between the xanthone structures and inhibition of microorganism activity.The antimicrobial activity of this plant was reported here firstly.The results provided evidence that the studied plant extract,fractions as well as some of the isolated compounds might be potential sources of new antimicrobial drug.

New Hemisynthetic Oleanane Saponin with Antimicrobial Activities

A new hemisynthetic oleanane saponin: 4',2",3",4",6"-penta-O-acetyl-6'-O- methyl-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranosyl oleanolic acid (2) was obtained after acetylation and methylation reaction on 3-O-β-D- glucopyranosyl-(1→2)-β-D-glucuronopyranosyl oleanolic acid (1). Its structure was established by extensive analysis of 1D-(1H, 13C), 2D-(COSY, HSQC and HMBC) NMR data in conjunction with mass spectrometry (HR- TOFESIMS). The evaluation of antimicrobial activities using microdilution method showed that, reaction product (2) presented the lowest values of MIC against E. coli (MIC = 16 μg/mL), S. aureus (MIC = 8 μg/mL), C. tropicalis (MIC = 16 μg/mL) C. albicans (MIC = 8 μg/mL) compare to the substrate (1) against the same microbial strains: E. coli (MIC = 32 μg/mL), S. aureus (MIC = 16 μg/mL), C. tropicalis (MIC = 32 μg/mL), C. albicans (MIC = 16 μg/mL). These results indicate that, acetylation and methylation reactions of compound 1 increase its antimicrobial activities against the tested microorganisms.

Antimicrobial activities of essential oil from Artemisiae argyi leaves

A study was conducted to determine the antimicrobial activities of essential oil from Artemisiae argyi leaves. The sample of the essential oil was analyzed by GC-MS. From 18 compounds representing the oils, Eucalyptole （18.42%）, Spathulenol （14.32）, 4-Methyl-1-（1-methylethyl）-3-cyclohexen-1-ol （3.10%）, 3-Carene （2.64%） appeared as the main components. The screening of antimicrobial activity of the essential oil was evaluated using agar diffusion and broth microdilution methods. Gram-positive bacterial were more sensitive than gram-negative bacterial of the 8 microorganisms, and Staphylococcus aureus ATCC 6538 showed the lowest MIC （0.3125%） and MBC （0.625%）. In the disc diffusion assay, Staphylococcus epidermidis ATCC 49134 and Bacillus subtilis ATCC 6633 showed obvious inhibitory activity. Survival curve showed that, 2MIC ofArtemisiae argyi essential oil had a lethal effect on Candida albicans within the first 1 h. Results presented here suggest that the essential oil of Artemisiae argyi leaves possesses antimicrobial properties, and provides scientific foundations for exploition ofArtemisiae argyi.

One-pot Synthesis,Crystal Structures and Antimicrobial Activities of Two New 1,4-Disubstituted 1,2,3-Triazole-4-Carboxylates

Two new 1,4-disubstituted 1,2,3-triazoles-4-carboxylates were synthesized via click reaction. Compound 1a was synthesized by the interaction of 6-nitro-tetrazolo[1.5-a]-pyridine with ethyl propynoate at room temperature in the presence of Cu（OAc）2 as a catalyst and THF as solvent. Compound 1b was also synthesized by the same manner except that tert-butyl propionate, instead of ethyl propynoate, was used. The compounds were characterized by IR, 1H-NMR, 13C-NMR and single-crystal X-ray diffraction analysis. Compound 1a（C10H9N5O4） crystallizes in the triclinic system, space group P1 with a = 5.0894（9）, b = 8.9834（13）, c = 13.089（2） ？, α= 83.041（7）, β= 80.256（7）, γ=87.296（8）°, V = 585.24（16）？3, Z = 2, Mr = 263.22, crystal size（mm） = 0.37 × 0.20 ×0.18,（I 〉 2σ（I）） = 8557, 2493, 1229, Rint = 0.057. Compound 1b（C12H13N5O4） crystallizes in the monoclinic system, space group P21/c with a = 6.8854（5）, b = 21.783（2）, c = 9.3986（8） ？,β = 93.239（4）°, V = 1407.4（2）？3, Z = 4, Mr = 291.27, crystal size（mm） = 0.38 × 0.22 × 0.20,（I 〉 2σ（I）） = 11842, 3172, 1866, Rint = 0.047. Antimicrobial assay results showed that the title compounds display excellent activities to different bacterial and fungal strains.

Syntheses,Crystal Structures,and Antimicrobial Activities of 3-Bromo-N'-(2- chloro-5-nitrobenzylidene)benzohydrazide and 3-Bromo-N'-(4-nitrobenzylidene)benzohydrazide

Two new hydrazone compounds, 3-bromo-N＇-（2-chloro-5-nitrobenzylidene）-ben- zohydrazide 1 and 3-bromo-N＇-（4-nitrobenzylidene）benzohydrazide 2, have been synthesized and characterized by elemental analysis, IR spectra, 1H NMR, and single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P21/c with a=7.7924（10）, b=24.490（3）, c=7.8989（9） , β=94.987（6）°, V=1501.7（3） 3, Z=4, R=0.0345 and wR=0.0739. Compound 2 crystallizes in monoclinic, space group P21/c with a=7.4099（11）, b=24.868（4）, c=8.3255（12） , β=112.796（8）°, V=1414.3（4） 3, Z=4, R=0.0744 and wR=0.1912. Both compounds display E configurations with respect to the C=N double bonds. In the crystal structure of 1, molecules are linked through N-H…N and N-H…O hydrogen bonds, forming chains running along the c axis. In the crystal structure of 2, molecules are linked through N-H…O hydrogen bonds, forming chains running along the c axis. The preliminary antimicrobial activities were studied.

Syntheses, Crystal Structures and Antimicrobial Activities of Vanadium(V) Complexes with Similar Tridentate Hydrazone Ligands

Two hydrazone ligands （E）-N＇-（2-hydroxy-5-methoxybenzylidene）-2-hydroxybenzo- hydrazide （HLa） and （E）-N＇-（3,5-dichloro-2- hydroxybenzylidene）-4-methoxybenzohydrazide （HLb） were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone ligands, two new structurally similar vanadium（V） complexes, [VOLaL].CH3OH （1） and [vOLbL] （2）, where L is the monoanionic form of benzohydroxamic acid （HL）, were prepared and characterized by IR and UV-Vis spectra, and single-crystal X-ray diffraction. Complex 1 crystallizes as the monoclinic space group P21/n, with a = 7.5208（10）, b = 15.490（2）, c = 20.8929（18） A, β = 96.373（2）°, V = 2418.9（5） A3, Z = 4, R = 0.0831, wR = 0.2607 and GOOF = 1.061. Complex 2 crystallizes as the monoclinic space group P21/c, with a = 11.8577（18）, b = 16.468（2）, c = 12.2288（18） A, β = 106.064（2）°, V= 2294.7（6） A3, Z = 4, R= 0.0741, wR= 0.1745 and GOOF= 1.014. X-ray analysis indicates that the complexes are mononuclear vanadium （V） species, with the V atoms located in the octahedral coordination. The hydrazone ligands and the complexes were evaluated for their antibacterial （Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence） and antifungal （Candida albicans and Aspergillus niger） activities by MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide） method.

Synthesis of Stable Silver Nanoparticles with Antimicrobial Activities in Room-temperature Ionic Liquids

Stable silver nanoparticles was successfully synthesized by chemical reduction of silver nitrate in an ionic liquid,1-n-butyl-3-methylimidazolium tetrafluoroborate（[BMIM]·BF4） at room temperature.Results of UV-Vis diffuse reflectance spectroscopy show as-prepared Ag nanoparticles exhibit a typical emission peak at 400―430 nm.By varying the reaction temperature and the precursor concentration,the size and the shape of the silver nanoparticles could be easily controlled under mild conditions.Analyses of transmission electron micrographs,X-ray diffraction pattern and X-ray photoelectron spectrum further reveal that the silver nanoparticles were coated incompletely by [BMIM]·BF4.Microbial experiments indicate that as-prepared silver nanoparticles show a wide spectrum of antimicrobial activities and have better antimicrobial activities to Pseudomonas aeruginosa than silver nitrate with the same concentration of silver.

Antioxidant and Antimicrobial Activities of Essential Oils Extracted from Laurus nobilis L.Leaves by Using Solvent-Free Microwave and Hydrodistillation

In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SFME) and hydrodistillation (HD) methods from Laurus nobilis leaves and determined their antioxidant and antimicrobial activity. Extraction time was reduced by about 43% in SFME at 622 W and 67% in SFME at 249 W compared to hydrodistillation. Essential oil of laurel was extracted by SFME at 622 W (100%) and 249 W (40%) power levels and HD inhibited oxidation generated by ABTS radical by 93.88%, 94.13% and 92.06%, respectively. Trolox equivalent antioxidant capacities (TEAC) of essential oils were 0.18 mM/mL oil for SFME at 622 W, 1.36 mM/mL oil for SFME at 249 W and 2.40 mM/mL oil for HD (p < 0.05). Essential oils of L. nobilis were extracted by SFME at 100% and 40% power levels and HD inhibited linoleic acid peroxidation by 70.57%, 63.53% and 89.18% respectively. Inhibition effects of laurel essential oils obtained by SFME at different power levels and HD on DPPH radical cation oxidation were not significantly different. The strongest antioxidant activity against DPPH radical was found in the essential oil obtained by SFME at 100% power level. Essential oils displayed antimicrobial activity against Staphylococcus aureus 6538P, Escherichia coli O157:H7 and Salmonella typhimurium NRRL E 4463 except for Listeria monocytogenes. The inhibitory effect on Staphylococcus aureus 6538P survival of laurel oil obtained from SFME by using lower power level was found to be lower than that obtained from SFME at 100% power level and HD

Phytochemical screening and in vitro evaluation of antioxidant and antimicrobial activities of Kedrostis africana(L.)Cogn

Objective: To investigate phytochemical, antioxidant and antimicrobial activities of Kedrostis africana(K. africana).Methods: Dried tubers of K. africana were extracted in acetone, water and ethanol. The total phenol, flavonoid, proanthocyanidin and tannin contents were determined spectrometrically. The antioxidant activity was examined using 2,2-diphenyl-1-picrylhydrazyl,2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt, nitric oxide and hydrogen peroxide assays. The antimicrobial activity was determined by agar dilution method using minimum inhibitory concentration against 3 g positive and three gram negative strains while four fungal strains were also investigated.Results: Total phenol, flavonoids, proanthocyanidin and tannin contents ranged from(5.32 ± 0.01) to(10.51 ± 0.01) mg GAE/g;(42.58 ± 0.02) to(529.23 ± 0.01) mg QE/g;(15.05 ± 0.00) to(585.64 ± 0.00) mg CE/g and(0.301 ± 0.010) to(0.937 ± 0.000) mg TAE/g, respectively. The IC_(50) values of the ethanol extract for 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and hydrogen peroxide were 0.054 and 0.057 mg/mL,respectively, aqueous extract had an IC_(50) value of 0.135 7 mg/mL for nitric oxide while the acetone extract had an IC_(50) value of 0.300 mg/mL for 2,2-diphenyl-1-picrylhydrazyl.The ethanol extract demonstrated effective antimicrobial activity against the tested pathogenic species with minimum inhibitory concentrations values ranging from 2.5–5.0 mg/mL for bacteria and(0.312 5–5.000 0) mg/mL for fungi, respectively.Conclusions: The tuber of K. africana showed potent free radical scavenging property and antimicrobial activity.

Triterpenoids and Semisynthetic Derivatives with Antimicrobial Activities from the Leaves of <i>Caloncoba glauca</i>(Flacourtiaceae)

Chemical investigation of the MeOH extract from the leaves of C. glauca yielded nine known triterpenoids (1-9) belonging to the cycloartane and friedelane series. Two of these compounds namely glaucartanoic acid A (1) and 3β,21β-dihydroxy-30-nor-(D:A)-friedoolean-20(29)-en-27-oic acid (5) were subjected to chemical derivatizations and afforded five new derivatives: diacetylglaucartanoic acid A (1a), 24-acetylglaucartanoic acid A (1b), glaucartanoic acid A methyl ester (1c), 24-methoxyglaucartanoic acid A methyl ester (1d), and 3β,21β-diacetoxy-30-nor-(D:A)-friedoolean-20(29)-en-27-oic acid (5a). Their structures were assigned based on their NMR and MS data and by comparison with literature values. The MeOH extract, isolated compounds and some new semi-synthetic derivatives were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms, including Gram-positive and Gram-negative bacteria, and fungi using broth microdilution method. The MeOH extract displayed activity towards all the tested pathogenic bacterial and fungal strains with good activity (MIC < 100 μg/mL) against Staphylococcus aureus ATCC25923 and Shigella flexneri SDINT. Compounds 3 and 5 showed the most potent antimicrobial effect.

Antagonistic Effect of Bacteria Isolated from the Digestive Tract of Lutzomyia evansi against Promastigotes of Leishmania infantum, Antimicrobial Activities and Susceptibility to Antibiotics

Lutzomyia evansi is a phlebotomine insect endemic to Colombia’s Caribbean coast and is considered the main vector of visceral and cutaneous leishmaniasis in the region. Specific studies of the direct effects generated by bacteria in the digestive tract of the insect vectors, under Leishmania infantum using in vitro models, represent a novel alternative as a control strategy for the transmission of leishmaniasis and also provide the opportunity to detect natural products or antimicrobial peptides with different biological activities. In this study, we evaluate the leishmanicidal and antimicrobial activities of Pantoea ananatis, Ochrobactrum anthropi and Enterobacter cloacae, isolated from the digestive tract of Lutzomyia evansi and the susceptibility of these bacteria to commonly used antibiotics. The antagonistic effect of Pantoea ananatis, Ochrobactrum anthropi and Enterobacter cloacae was evaluated against six species of human pathogenic bacteria and against stationary (Metacyclic-like) and exponential promastigotes (Procyclic-like) of Leishmania infantum (BCN-GFP strain) by co-culture assays for 24 hours. The activity of the bacterial isolates on Leishmania infantum promastigotes was quantified by flow cytometry. The susceptibility of the bacterial strains to clinically used antibiotics was analyzed by antibiogram. The highest percentage of inhibition was observed against exponential promastigotes with bacterial concentrations of 108 CFU/ml of Enterobacter cloacae (77.29% ± 0.6%) and Pantoea ananatis (70.17% ± 1.1%). The extracts produced by three bacterial isolates showed similar biological activity (13 mm - 22 mm inhibition halos) against all tested bacteria;however, significant differences were observed with respect to gram-positive bacteria (P < 0.003557). The most active antibacterial activity was displayed against the pathogenic bacteria Bacillus cereus. Ochrobactrum anthropi was the isolate with the highest number of antibiotic resistance patterns while Pantoea ananatis and Enterobacter cloacae showed greater susceptibility to the evaluated antibiotics. The growth inhibitory activity of exponential Leishmania infantum promastigotes shown by extracts of Enterobacter cloacae and Pantoea ananantis suggests that the presence of these bacteria in the vector intestine may affect the parasite development to metacyclic stages, infective to human hosts. This in turn confers said bacteria, a potential in controlling the transmission of Leishmania spp. that deserves to be studied in depth.

Antioxidant,antimicrobial,and α-glucosidase inhibitory activities of saponin extracts from walnut(Juglans regia L.) leaves

Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.

LC-MS Phytochemical Profiles of Phenolic Compounds and Antimicrobial, Antioxidant, and Antiplasmodial Activities of Ethanol Extracts of Pycnostachys erici-rosenii R.E.Fr and Leucas martinicensis (Jack.) R.Br (Lamiaceae)

This study has been conducted to analyze the chemical composition and antimicrobial, antioxidant and antiplasmodial properties of ethanol extracts of Pycnostachys erici-rosenii R.E.Fr and Leucas martinicensis (Jack.) R.Br that are not yet well known. The HPLC-DAD-MS-ESI+ method was used to investigate the chemical profile, the disc diffusion and microdilution method for the antimicrobial activities, the DPPH and FRAP assays for antioxidant property and SYBR Green I-based growth inhibition assay on Pf 3D7 (CQ-sensitive) strain for antiplasmodial properties. The results indicated significant amounts of hydroxybenzoic acid, flavonol and hydroxycinnamic acid in the two species. The total polyphenols analysis gave 209.0 ± 16.1 mg GAE/100g DW for P. erici-rosenii and 175.3 ± 1.6 mg GAE/100g DW for L. martinicensis while for total flavonoids analysis 33.4 ± 1.8 mg TE/100g DW was found for P. erici-rosenii and 39.6 ± 0.6 mg TE/100g DW for L. martinicensis. Moreover, antimicrobial tests revealed 0.125 mg/mL on E. faecalis ATCC25922 for ethanol extracts P. erici-rosenii and L. martinicensis. The antioxidant assays revealed IC50 56.17 μg/mL and 78.43 μg/mL for DPPH assay, and 112.03 μM TE/100mL and 90.46 μM TE/100mL) for FRAP assay for ethanol extracts of P. erici-rosenii and L. martinicensis respectively. Finally, for Antiplasmodial activity, IC50 was 4.07 μg/mL for P. erici-rosenii and 12.29 μg/mL for L. martinicensis. Therefore, the antimicrobial, the antioxidant, and the antiplasmodial results suggest that the ethanolic extracts of the aerial parts of P. erici-rosenii and L. martinicensis contain compounds with antimicrobial, antioxidant, and antiplasmodial properties, which can be searched in new drug discovery for treatment of infectious diseases.

Phytochemical Analysis and Antimicrobial Activity of Lawsonia inermis Leaf Extracts from Burkina Faso

Lawsonia inermis is a hairless plant growing in various regions of North Africa, the Indian subcontinent, and the Middle East. It possesses many medicinal attributes, including curative properties against infectious dermatoses. This study was carried out to evaluate the phytochemical profile of the crude ethanolic extract of the plant leaves and its fractions as well as their antimicrobial activities. The phytochemical profile was performed using high-performance thin-layer chromatography (HPTLC), gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC). Additionally, the phenolic and flavonoid contents were determined using the Folin-Ciocalteu spectrophotometric and the aluminum trichloride methods. Antimicrobial activity was tested using disc diffusion and microdilution methods. The presence of flavonoids, tannins, sterols, and triterpenes was revealed. GC-MS detected twelve compounds main compounds consisting of saturated and unsaturated fatty acids and phenolic and terpenoid compounds among twenty-seven components. HPLC also detected high contents of phenolic acids and flavonoids. The most abundant triterpene and sterols were ursolic acid (around 43.14 g/100g DW, 13.9 g/100g dry weight (DW), and 0.68 g/100g DW) in the crude ethanolic extract of leaves (FeLi), hexane fraction (FHLi) and dichloromethane fraction (FDLi), respectively and, β-sitosterol in FeLi (56.7 mg/100g DW), FHLi (10.55 g/100g DW), FDLi (106.1 mg/100g DW) and butanol fraction (FBLi) (357.4 mg/100g DW). Among the flavonoids, rutin = 3.24 g/100g and quercetin = 0.63 g/100g in the ethanolic extract, rutin = 15.73 g/100g in the dichloromethane fraction, and rutin = 0.23 g/100g) in the aqueous fraction;and among phenolic compounds, caffeic acid (37.65 g/100g DW) and vanillic acid (22.70 g/100g DW) were the most important in the ethyl acetate fraction (FAeLi). All organic fractions exhibited interesting antibacterial and antifungal activities against the tested strains, with the best activity recorded with the dichloromethane and ethyl acetate fractions. The leaf extracts’ phytochemical profile and antimicrobial activity support the use of Lawsonia inermis against infectious skin diseases.

Biosynthesis of Silver Nanoparticles with Clerodendron phlomoides Leave Extract:Particle Morphology,Antimicrobial Potential and Application

Silver nanoparticles are versatile nanomaterials that have found numerous applications in various fields.The use of plant extract for the synthesis of silver is a green and sustainable approach.Clerodendron phlomoides leaves extract has been found to contain various phytochemicals,such as phenols,flavonoids,tannins,and alkaloids,which possess reducing and stabilizing properties that can aid the production of silver particles.In this paper,morphological and topographical analyses were performed on silver nanoparticles.The biosynthesized silver nanoparticles showed antimicrobial potential against wound pathogens.SEM and TEM micrographs revealed that the particles were sphere and nanosized,which makes them suitable for various biomedical applications.

Biosynthesis of Copper Nanoparticles using an Extract of the root of Asparagus racemosus:Basic Synthesis,Antimicrobial,and Anti-oxidant Potentials

Copper nanoparticles(CuNPs)have emerged as a promising alternative due to their unique antimicrobial properties.The synthesis of CuNPs using Asparagus racemosus,commonly known as Shatavari,offers a sustainable and environmentally friendly approach to producing nanomaterials.Moreover,the resulting CuNPs have been found to possess excellent antibacterial,and antioxidant properties,which further expands their potential applications in medicine and environmental remediation.In this article,we discussed the in vitro characterization of the CuNPs.In vitro studies revealed that CuNPs have the potential for biomedical applications and as a base nanomaterial for the construction of drug delivery and targeting vehicles.

Chemical composition,antioxidant and antimicrobial activities of the essential oil of Santolina chamaecyparissus L.of Algeria

Objective:To investigate the chemical composition,antioxidant and antimicrobial activities of essential oil of Santolina chamaecyparissus L.cultivated in Algeria.Methods:The chemical composition of hydrodistilled essential oil from flowering aerial parts has been analyzed by gas chromatograph and gas chromatograph-mass spectrometer techniques.The antioxidant activities conducted by 2,2-diphenyl-1-picrylhydrazyl scavenging test andβ-carotene bleaching test.The antimicrobial activity was realised by agar disc diffusion method and cornell medical index was determined by agar dilution method in solid medium.Results:About 36 components accounting more than 82%of the total oil were identified.Oxygenated monoterpenes was the main fraction(54.66%)and was represented by artemisia ketone(40.33%)as major component of this oil.The other major constituents were(Z)-thujone(9.82%),(2Z,6E)-farnesol(7.30%)and limonene(6.87%)and concerning antiradical scavenging test(2,2-diphenyl-1-picrylhydrazyl)had demonstrated a weak activity obtained with an EC_(50) of(43.01±8.04)and moderate activity for β-carotene bleaching test(47.00±3.13)at 120 min.In the other hand,this oil was found effective against all tested strains except Pseudomonas aeruginosa and Aspergillus species.This activity was ranging from 10 mm to 24 mm with the lowest minimum inhibitory concentration value between under 0.070μg/mL to upper 9μg/mL.Conclusions:The results provided evidence that the studied plant might indeed be potential sources of natural antioxidant and antimicrobial agents.

A pilot survey on antimicrobial activity and diversity of soil-derived actinobacteria from different depths in Gudzhirganskoe saline lake in Eastern Siberia

To explore pharmaceutical actinobacteria from salty environments in Siberia,8 soil samples were collected from different depths of Gudzhirganskoe saline lake,the Republic of Buryatia,Russia.Totally,635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches.The predominant genus was Streptomyces(74.5%),followed by Microbacterium(4.9%),Agromyces(3.5%),Nocardiopsis(3.0%),and Kitasatospora(2.5%).Seven strains showed relatively low 16 S rRNA similarities(<98.65%)with validly described species.Seventy-seven strains were selected as representatives to evaluate their antimicrobial activities and underlying mechanisms by paper-disk diffusion method and a double fluorescent protein reporter system(pDualrep 2),respectively.Streptomyces sp.S 6 b 3-1 was highlighted due to its strong inhibitory activities against Gram-positive bacteria and underlying antibacterial mechanism by inducing the SOS response in the reporter system.LG-1,(R)-6-[1-(benzoyloxy)ethyl]-phenazine-1-carboxylic acid,an analogue of saphenamycin was finally isolated from the culture broth of Streptomyces strain.This study preliminarily explored the actinobacterial diversity of soil samples collected in the highly alkaline and saline lake Gudzhirganskoe by culture-dependent approach and their capacity to produce antibiotics for the first time,which revealed that it deserves to make more efforts to discover new actinobacterial species and potential new antibiotics from the saline lake in Eastern Siberia.

Phytochemical, Anti-oxidant, Larvicidal, and Antimicrobial Activities of Castor(Ricinus communis) Synthesized Silver Nanoparticles

Objective Castor possesses the medicinal properties. Hence, castor extract has the reducing power agent was used in nanoparticles synthesis. Extract of castor also produces secondary metabolites （phenolics, reducing agent） and exhibits anti-oxidant property, which was used as larvicide and antimicrobial agent. In the present study the silver nanoparticles （AgNPs） were synthesized using aqueous leaf extract of castor. Methods The synthesized AgNPs were characterized with UV-visible spectroscopy and transmission electron microscopy （TEM）. The phenolics, reducing sugar and total sugar were evaluated performing Folin-Ciocalteu reagent method, DNS method and Phenol-sulphuric acid method. Anti-oxidant activity of synthesized nanoparticles was evaluated using DPPH assay. The larvicidal activity of synthesized AgNPs was evaluated against the third instar of Anopheles stephensi and Aedes aegypti. The mortality was observed after 24 h by probit analysis. Further, the antimicrobial activity was reported against Staphylococcus aureus （Gram positive） and Pseudomonas aeruginosa （Gram negative）. Results The UV spectra showed maximum absorbance at 445 nm and TEM analysis indicated spherical shape of nanoparticles with average size of 8.96 nm. The synthesized nanoparticles also possessed anti-oxidant potentials. Thus, it could be used as potential free radical scavenger. The larvae of A. stephensiwere found more susceptible to AgNPs than larvae of A. aegyptL Conclusion Due to the medicinal properties and reducing power activity, in the present study AgNPs have been synthesized using the aqueous leaves extract of castor and access their phytochemical, anti-oxidant, larvicidal and antimicrobial properties.