Combined antibacterial activity of stingless bee (Apis mellipodae) honey and garlic (Allium sativum) extracts against standard and clinical pathogenic bacteria

Objective

To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria.

Methods

Antimicrobial activity of tazma honey, garlic and mixture of them against pathogenic bacteria were determined. Chloramphenicol and water were used as positive and negative controls, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of antimicrobial samples were determined using standard methods.

Results

Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly (P≤0.05) greater than garlic and tazma honey alone. The diameter zone of inhibition ranged from (18±1) to (35±1) mm for mixture of garlic and tazma honey, (12±1) to (20±1) mm for tazma honey and (14±1) to (22±1) mm for garlic as compared with (10±1) to (30±1) mm for chloramphenicol. The combination of garlic and tazma honey (30-35 mm) was more significantly (P≤0.05) effective against Salmonella (NCTC 8385), Staphylococcus aureus (ATCC 25923), Lyesria moncytogenes (ATCC 19116) and Streptococcus pneumonia (ATCC 63). Results also showed considerable antimicrobial activity of garlic and tazma honey. MIC of mixture of garlic and tazma honey at 6.25% against total test bacteria was 88.9%. MIC of mixture of garlic and tazma honey at 6.25% against Gram positive and negative were 100% and 83.33%, respectively. The bactericidal activities of garlic, tazma honey, and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25% concentration were 66.6%, 55.6% and 55.6%, respectively.

Conclusions

This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections. Therefore, garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections. Further in vivo study is recommended to come up with a comprehensive conclusion.     

Biocompatibility of folate-modified chitosan nanoparticles

Objective

To evaluate the acute toxicity of carboxymethyl chitosan-2, 2′ ethylenedioxy bis-ethylamine-folate (CMC-EDBE-FA) and as well as possible effect on microbial growth and in vitro cell cyto-toxicity.

Methods

CMC-EDBE-FA was prepared on basis of carboxymethyl chitosan tagged with folic acid by covalently linkage through 2, 2′ ethylenedioxy bis-ethylamine. In vivo acute toxicity, in vitro cyto-toxicity and antimicrobial activity of CMC-EDBE-FA nanoparticle were determined.

Results

Vancomycin exhibited the antibacterial activity against vancomycin sensitive Staphylococcus aureus, but CMC-EDBE-FA nanoparticle did not give any antibacterial activity as evidenced by minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), disc agar diffusion (DAD) and killing kinetic assay. Further, the CMC-EDBE-FA nanoparticle showed no signs of in vivo acute toxicity up to a dose level of 1 000 mg/kg p.o., and as well as in vitro cyto-toxicity up to 250 µg/mL.

Conclusions

These findings suggest that CMC-EDBE-FA nanoparticle is expected to be safe for biomedical applications.     

Bioactive glass S53P4 eradicates Staphylococcus aureus in biofilm/planktonic states in vitro

Background: Increasing antimicrobial resistance to antibiotics is a substantial health threat. Bioactive glass S53P4 (BAG) has an antimicrobial effect that can reduce the use of antibiotics. The aim of this study was to evaluate the antimicrobial efficacy of BAG in vitro on staphylococci in biofilm and in planktonic form. Secondary aims were to investigate whether supernatant fluid primed from BAG retains the antibacterial capacity and if ciprofloxacin enhances the effect.Methods: BAG-S53P4 granules, <45 µm, primed in tryptic soy broth (TSB) were investigated with granules present in TSB (100 mg/mL) and after removal of granules (100, 200, and 400 mg/mL). The efficacy of BAG to eradicate Staphylococcus aureus biofilm in vitro was tested using 10 different clinical strains and 1 reference strain in three test systems: the biofilm-oriented antiseptic test based on metabolic activity, the biofilm bactericidal test based on culturing surviving bacteria, and confocal laser scanning microscopy (CLSM) combined with LIVE/DEAD staining.Results: Exposure to 48 h primed BAG granules (100 mg/mL) produced bactericidal effects in 11/11 strains (p = 0.001), and CLSM showed reduction of viable bacteria in biofilm (p = 0.001). Supernatant primed 14 days, 400 mg/mL, reduced metabolic activity (p < 0.001), showed bactericidal effects for 11/11 strains (p = 0.001), and CLSM showed fewer viable bacteria (p = 0.001). The supernatant primed for 48 h, or in concentrations lower than 400 mg/mL at 14 days, did not completely eradicate biofilm.Conclusion: Direct exposure to BAG granules, or primed supernatant fluid, effectively eradicated S. aureus in biofilm. The anti-biofilm effect is time- and concentration-dependent. When BAG had reached its full antimicrobial effect, ciprofloxacin had no additional effect.     

The antimicrobial activity of ceftobiprole against Methicillin-resistant Staphylococcus aureus and multi-drug resistant Pseudomonas aeruginosa : A large tertiary care university hospital experience in Riyadh,Saudi Arabia

Objectives:To assess the antibacterial activity of ceftobiprole against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) from various body specimen types and different patterns of resistance.Methods:A retrospective cohort study with a total of 49 MRSA and 99 P. aeruginosa isolated in the Microbiology Laboratory at King Saud University Medical City, Riyadh, Saudi Arabia, between 2018-2019, were used. Isolates were randomly selected from various specimen types. The minimum inhibition concentration (MIC) of ceftobiprole was determined by E-test. Breakpoints carried out by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) were used to assess antibiotic susceptibility.Results:Approximately 100% of the MRSA isolates were susceptible with MIC50/90 value of 1/1.5 mg/L while 69.8% of multi-drug resistant (MDR) P. aeruginosa isolates were resistant with MIC50/90 value of 16/32 mg/L.Conclusion:The excellent activity of ceftobiprole against MRSA would have major implications in management of the patients with serious infections, as an empirical treatment or alternative to vancomycin. Ceftobiprole has a very low activity against MDR P. aeruginosa, and its susceptibility should be tested prior to use for treatment.     

Essential oils of Origanum compactum increase membrane permeability,disturb cell membrane integrity,and suppress quorum-sensing phenotype in bacteria

The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was evaluated using the agar-well diffusion assay. The MIC and MBC values were determined using the micro-dilution assay. The investigation of the antibacterial action was carried out by the evaluation of the effect of O. compactum essential oils on the antibacterial kinetic growth, the integrity of cell membrane and permeability of the cell membrane. The anti-quorum sensing activity was tested by the inhibition of the biofilm formation. The findings of this study showed that O. compactum essential oil has potent antibacterial activities against E. coli and B. subtilis. The lowest inhibition value against B. subtilis was obtained with O. compactum essential oil at the post-flowering stage (MIC = MBC = 0.0312% (v/v)). The antibacterial mechanisms of O. compactum essential oils are related to the disturbing of the cell membrane integrity and the increasing of the membrane permeability, which leads to the leakage of genetic materials (DNA and RNA). Moreover, O. compactum essential oils inhibited the formation of the biofilms, a phenotype that has been known to be quorum sensing regulated.     

葡萄籽原花青素对变形链球菌的体外抗菌活性研究

目的?研究葡萄籽原花青素（Grape seed procyanidins,GSPC）对变形链球菌的体外抗菌活性,探讨其防龋潜能。方法?采用微量肉汤法测定最低抑菌浓度（MIC）、最低杀菌浓度（MBC）、最低抑制生物膜浓度（MBIC）;采用结晶紫半定量法测定生物膜生成量;硫酸-蒽酮法测定产糖量,pH计测定产酸量。结果?葡萄籽原花青素的MIC值12.5?mg/mL;MBC值和MBIC值均为50?mg/mL;GSPC（≥12.5?mg/mL）降低变形链球菌生物膜的生成量,8倍MIC浓度（100?mg/mL）时抑制率达76%;GSPC在低于MIC浓度时仍具有抑制变形链球菌产糖、产酸能力。结论?葡萄籽原花青素具有对变形链球菌的体外抗菌活性,并能抑制变形链球菌的生物膜和致龋毒力因子。      

Antimicrobial activity against periodontopathogenic bacteria,antioxidant and cytotoxic effects of various extracts from endemic Thermopsis turcica

ObjectiveTo investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan, Vural & Küçüködük against periodontopathogenic bacteria, its antioxidant activity and cytotoxic effect on various cancer cell lines.MethodsIn vitro antimicrobial activities of ethanol, methanol, ethyl acetate (EtAc), n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Antioxidant properties of the extracts were evaluated by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and β-carotene bleaching methods. Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent. Additionally, cytotoxic activity of the extracts on androgen-insensitive prostate cancer, androgen-sensitive prostate cancer, chronic myelogenous leukemia and acute promyelocytic leukemia human cancer cell lines were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human gingival fibroblast cells were used as a control.ResultsOur data showed that EtAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemcomitans (MIC: 1.562 mg/mL, MBC: 3.124 mg/mL) and Porphyromonas gingivalis (MIC: 0.781 mg/mL, MBC: 1.562 mg/mL). In antioxidant assays, EtAc extract exhibited also the highest radical scavenging activity [IC₅₀=(30.0±0.3) μg/mL] and the highest inhibition [(74.35±0.30)%] against lineloic acide oxidation. The amount of phenolic content of it was also the highest [(162.5±1.2) μg/mg gallic acid]. In cytotoxic assay, only ethanol [IC₅₀=(80.00±1.21) μg/mL] and EtAc extract [IC₅₀=(70.0±0.9) μg/mL] were toxic on acute promyelocytic leukemia cells at 20-100 μg/mL (P<0.05). However, no toxic effect was observed on human gingival fibroblast cells.ConclusionsAccording to our findings, owing to its antioxidant and cytotoxic potential, EtAc extract might include anticancer agents for acute promyelocytic leukemia.     

Antimicrobial activity of green tea extract against isolates of methicillin-resistant Staphylococcus aureus and multi-drug resistant Pseudomonas aeruginosa

Objective

To evaluate antibacterial activity of the Indonesian water soluble green tea extract, Camellia sinensis, against clinical isolates of methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) and multi-drug resistant Pseudomonas aeruginosa (MDR-P. aeruginosa).

Methods

Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration (MIC) was determined by the twofold serial broth dilutions method. The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S. aureus and P. aeruginosa, obtained from Laboratory of Clinical Microbiology, Faculty of Medicine, University of Indonesia.

Results

The results showed that the inhibition zone diameter of green tea extracts for S. aureus ATCC 25923 and MRSA were (18.970±0.287) mm, and (19.130±0.250) mm respectively. While the inhibition zone diameter for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were (17.550±0.393) mm and (17.670±0.398) mm respectively. The MIC of green tea extracts against S. aureus ATCC 25923 and MRSA were 400 µg/mL and 400 µg/mL, respectively, whereas the MIC for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were 800 µg/mL, and 800 µg/mL, respectively.

Conclusions

Camellia sinensis leaves extract could be useful in combating emerging drug-resistance caused by MRSA and P. aeruginosa.     

如何保持过氧化氢的抗菌作用：中药的崭新作用

Objective： To explore natural herbs to maintain the bactericidal activity of hydrogen peroxide （H2O2）. Methods： Eighteen extracts of Chinese herbs were prepared complying with the standard protocol. Each of the solutions was then mixed with 1% H2O2. The mixtures were handled with two approaches： autoclaved daily for one, two or three times; stored at room temperature from one through five years. Then the bactericidal activity were evaluated by assaying the minimal bactericidal concentration （MBC） and minimal inhibitory concentration （MIC） against Gram positive （Staphylococcus aureus, ATCC25923） and Gram negative （Escherichia coli, ATCC12421） bacteria. Results： While mixed with 1% H2O2, 10 out of 18 kinds of assessed Chinese herbs displayed MBC values at 1：12800 or higher after three times of autoclaving, and 8 of them preserved such level of MBC value after stored at room temperature for three years. Some Chinese herbs, i.e. Fl. Scutellariae, R. Coptidis, R. Bupleuri, H. Epimedii, C. Phelledendri and F. Chrysanthemi, can significantly maintain the bactericidal activity of diluted H2O2. Conclusions： Certain Chinese herbs can effectively stabilize the bactericidal activity of H2O2 undergoing autoclave or long-term storage. This paper reported a brandnew pharmaceutical function of Chinese herbs and provided experimental data for the potential enhancement of H2O2 usage while its stability level is promoted.     

亚抑菌浓度隐丹参酮对表皮葡萄球菌生物膜形成的影响

目的:探讨亚抑菌浓度隐丹参酮对表皮葡萄球菌生物膜形成的影响。方法:以万古霉素为药物对照,微量稀释法测定隐丹参酮与万古霉素对表皮葡萄球菌的MIC值;半定量粘附实验、XTT、扫描电镜和RT-PCR分别检测1/2MIC浓度的隐丹参酮与万古霉素作用下表皮葡萄球菌生物膜基质量、膜内菌代谢活性、微观形态结构和atl E基因表达情况的变化。结果:隐丹参酮与万古霉素对表皮葡萄球菌的MIC值分别为2μg/m L与4μg/m L;1μg/m L的隐丹参酮与2μg/m L的万古霉素均能抑制表皮葡萄球菌生物膜基质量、膜内菌代谢活性和atl E基因表达,且1μg/m L的隐丹参酮抑制作用明显强于2μg/m L的万古霉素,差异有统计学意义(P0.05);SEM观察1μg/m L的隐丹参酮作用下表皮葡萄球菌已不能形成生物膜结构,而2μg/m L的万古霉素作用下依然能够形成生物膜结构。结论:亚抑菌浓度下的隐丹参酮能抑制表皮葡萄球菌生物膜形成,且抑制作用强于亚抑菌浓度万古霉素。     

清肺消炎丸体外抗菌活性研究

目的 观察清肺消炎丸对9种肺炎常见病原菌的体外抗菌作用。方法 采用琼脂稀释法,测定清肺消炎丸对9种药敏质控菌株的最低抑菌浓度（MIC）及最低杀菌浓度（MBC）。结果 清肺消炎丸对肺炎链球菌、化脓性链球菌、金黄色葡萄球菌、流感嗜血杆菌的MIC分别为6.25、25、25、50 mg/mL,相应的MBC分别为12.5、25、50、50 mg/mL;对大肠杆菌、铜绿假单胞菌、肺炎克雷伯菌、变形杆菌及白色念珠菌均无明显体外抑菌活性。结论 清肺消炎丸对肺炎链球菌、化脓性链球菌、金黄色葡萄球菌、流感嗜血杆菌具有体外抗菌作用,其中对链球菌的抗菌活性较高。     

In?vitro vancomycin susceptibility amongst methicillin resistant Staphylococcus aureus

Background

Vancomycin is drug of choice for treatment of Methicillin Resistant Staphylococcus aureus (MRSA) infections. S. aureus with reduced vancomycin susceptibility (SA-RVS) is on rise. Current guidelines of detection of SA-RVS are based on MIC (Minimum Inhibitory Concentration) by broth or agar dilution methods. Vancomycin MIC by E test (Epsilometer Test) is an alternative. A study was undertaken to know the prevalence of SA-RVS and compare vancomycin MIC by agar dilution and E test.

Methods

A prospective study was undertaken at tertiary care hospital; 232 clinical MRSA isolates were included. Vancomycin MIC was undertaken by agar dilution method and E test.

Results

All isolates were sensitive to Linezolid. Two MRSA isolates had vancomycin MIC ≥4 μg/ml; vancomycin MIC50 and MIC90 of MRSA isolates was 0.5 and 0.2 μg/ml respectively by agar dilution method. There was agreement over 93.5% isolates in vancomycin susceptibility by agar dilution and E test. E test had sensitivity and positive predictive value of 1.0 (CI – 0.34–1.0) and 0.5 (CI – 0.17–0.83) respectively compare to agar dilution method.

Conclusions

MRSA isolates continues to be susceptible to vancomycin and Linezolid. E test was found equally suitable in initial screening for vancomycin susceptibility. Due to geographic variation in prevalence, there is need of ongoing surveillance of SA-RVC.     

复方三黄酊体外抑菌活性的研究

目的 评价两种不同工艺制备的抗感染药物复方三黄酊的体外抗菌活性。方法 采用抑菌圈试验和胰酪大豆胨液体培养基稀释法对大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌、沙门氏菌和白色念珠菌进行体外抑菌试验,进行了最低抑菌浓度(MIC)和最低杀菌浓度(MBC)的试验研究。结果 两种工艺制备的抗感染药物复方三黄酊对金黄色葡萄球菌、铜绿假单胞菌和白色念珠菌具有较强的抑菌和杀菌活性,以金黄色葡萄球菌较为敏感。结论 本院生产的抗感染药物复方三黄酊具有明显的体外抑菌活性。     

Evaluation of antimicrobial activity and bronchodialator effect of a polyherbal drug-Shrishadi

Objective

To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha (Albezzia lebbeck), Nagarmotha (Cyprus rotandus) & Kantakari (Solanum xanthocarpum).

Methods

Antimicrobial activity was evaluated by disc diffusion method and MIC, MBC, MFC were calculated by micro dilution method. Hydroalcholic extract of this preparation was investigated for its phytochemical analysis, phenol and flavonoid were determined by spectrophotometric method and in vivo bronchodilator effect was analysed by convulsion time.

Results

The phytochemical tests revealed presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial result showed the MIC of 6.25 mg/mL against Staphylococcus aureus and 12.5 mg/mL for Escherichia coli and 12.5 mg/mL against remaining bacteria tested, with strong antifungal activity. The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL. Drug showed significant bronchodilator effect with 27.86% & 36.13% increase in preconvulsion time of guinea pigs pretreated with 100 & 200 mg/kg body weight of extract.

Conclusions

The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins, further studies are highly needed for the drug development.     

In vitro control of Staphylococcus aureus (NCTC 6571) and Escherichia coli (ATCC 25922) by Ricinus communis L.

Objective

To evaluate antibacterial activity of hot and cold ethanol and methanol leaf extracts of Ricinus communis L (R. communis) against Staphylococcus aureus (S. aureus) (NCTC 6571) and Escherichia coli (E. coli) (ATCC 25922).

Methods

Leaf powder of R. communis L. was extracted with hot (in Soxhlet) and cold ethanol and methanol, separately. The antibacterial activity of the extracts was determined by agar well diffusion and macro broth dilution methods. The extracts were also subjected to phytochemical analysis.

Results

All the four test extracts showed inhibition on both S. aureus and E. coli. Hot and cold ethanol extracts revealed significantly (P<0.05) higher inhibition on S. aureus than methanol extracts, and the hot ethanol extract had the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (5 mg/mL and 10 mg/mL, respectively). E. coli was highly inhibited by hot extracts of both ethanol and methanol with the MIC and MBC of 40 mg/mL and 80 mg/mL, respectively. Phytochemical analysis revealed the presence of saponins, cardiac glycosides, tannins, flavonoids and terpenoids in all test extracts.

Conclusions

This study demonstrates that the hot and cold methanol and ethanol extracts are potential sources for control of S. aureus and E. coli. Especially, the hot and cold extracts of ethanol are more inhibitive against S. aureus even at lower concentration. Further study is needed to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.     

黄芩素对金黄色葡萄球菌生物膜抑制作用的体外研究

目的研究黄芩素(Baicalein)对金黄色葡萄球菌(S.a)早期、成熟生物膜(biofilm,BF)的抑制作用。方法以编号为17546金黄色葡萄球菌为实验菌株,构建体外BF模型。分为空白对照组、实验组(黄芩素组),二倍稀释法测定最低抑菌浓度(MIC);荧光显微镜观察载体表面BF形态;连续稀释法行活菌计数。结果建模3 d,荧光显微镜发现黄芩素终浓度分别为128μg/mL、64μg/mL、32μg/mL的实验组形成BF明显少于空白对照组,载体表面活菌计数(x±s,log10CFU/mL)分别为4.00±0.27、4.24±0.31、5.26±0.45,均少于空白对照组活菌计数5.69±0.18(P<0.05);建模7 d荧光显微镜观察,黄芩素终浓度分别为128μg/mL、64μg/mL、32μg/mL的实验组仅见少许散在生物膜,BF结构较空白对照组明显稀薄,其BF内细菌活菌计数(x±s,log10CFU/mL)分别为4.04±0.12、4.69±0.41、5.63±0.10亦均少于空白对照组活菌计数6.08±0.10(P<0.05)。结论黄芩素在体外可以抑制金黄色葡萄球菌生物膜的形成。     

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

ObjectiveTo evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and methicillin resistance S. aureus.MethodsThe crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S. aureus and methicillin resistance S. aureus using agar well diffusion method.ResultsIn Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra.ConclusionsThe potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.     

Biocompatible silver nanoparticles: An investigation into their protein binding efficacies,anti-bacterial effects and cell cytotoxicity studies

Green synthesis of silver nanoparticles (AgNPs) has garnered tremendous interest as conventional methods include the use and production of toxic chemicals, products, by-products and reagents. In this regard, the synthesis of AgNPs using green tea (GT) extract and two of its components, (−)-epigallocatechin gallate (EGCG) and (+)-catechin (Ct) as capping/stabilizing agents, is reported. The synthesized AgNPs showed antibacterial activity against the bacterial strains Staphylococcus aureus and Escherichia coli, along with anticancer activity against HeLa cells. After administering nanoparticles to the body, they come in contact with proteins and results in the formation of a protein corona; hence we studied the interactions of these biocompatible AgNPs with hen egg white lysozyme (HEWL) as a carrier protein. Static quenching mechanism was accountable for the quenching of HEWL fluorescence by the AgNPs. The binding constant (K_b) was found to be higher for EGCG-AgNPs ((2.309 ± 0.018) × 10⁴ M⁻¹) than for GT-AgNPs and Ct-AgNPs towards HEWL. EGCG-AgNPs increased the polarity near the binding site while Ct-AgNPs caused the opposite effect, but GT-AgNPs had no such observable effects. Circular dichroism studies indicated that the AgNPs had no such appreciable impact on the secondary structure of HEWL. The key findings of this research included the synthesis of AgNPs using GT extract and its constituent polyphenols, and showed significant antibacterial, anticancer and protein-binding properties. The –OH groups of the polyphenols drive the in situ capping/stabilization of the AgNPs during synthesis, which might offer new opportunities having implications for nanomedicine and nanodiagnostics.     

Effect of short duration moderate intensity physical activity on glycemic control and antioxidant status of prediabetic population

Objectives:To determine the effect of moderate-intensity physical activity on glycemic control and antioxidant status in the prediabetic population.Methods:This experimental study was carried out in the Physiology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan. A total of 50 adult prediabetic subjects having 22 females and 28 males with the age range of 18 to 35 years were included. Diagnosis of prediabetes was made by glycated hemoglobin falling in the range of 5.7-6.4%, and impaired fasting glucose (100-125 mg/dL). Anthropometric measurements and biochemical assays were carried out at pre and post-exercise intervention. The participants performed moderate exercise of 30 min with heart rate max 7% ± 5% for 5 days a week for 8 weeks, monitored with pedometer. Enzyme-linked immunosorbent assay was carried out for individual and total antioxidants.Results:Anthropometric parameters showed a significant decrease at post-exercise analysis. Similar changes were observed for fasting glucose (p<0.001) and glycated hemoglobin (p<0.001). Slight increase in uric acid (p<0.005) and total antioxidant concentration (p<0.001) were found. However, superoxide dismutase, glutathione peroxidase, vitamin C, and nitric oxide decreased (p<0.001).Conclusion:Moderate physical activity for 8 weeks significantly reduced the individual antioxidant levels, nominal increase in total antioxidant capacity and uric acid, and there was an explicit decline in the anthropometric and diabetic profile of prediabetic population.     

Screening of biological activities of Polygonum maritimum L. from Algerian coast

Objective

To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimum L. (Polygonaceae) (P. maritimum) and to find new actives biomolecules.

Methods

The whole plant was collected from the Rechgoune coast (West of Algeria), and methanolic crude extract of aerial parts of P. maritimum (PMCE) was prepared. The extract was tested against different bacterial strain and tested for his ability to neutralize free radical (DPPH) and to scavenge the H₂O₂.

Results

PMCE had a very high content of total phenol, which was (352.49±18.03) mg/g dry weight, expressed as gallic acid equivalent. PMCE exhibited excellent antioxidant activity, as measured using DPPH and H₂O₂ scavenging assays. It also showed a high antibacterial activity against gram-positive bacterial strains: Bacillus cereus, Bacillus subtilis and Staphylococcus aureus with an highest MIC of 120 µg/mL.

Conclusions

The antioxidant and antibacterial activity of the PMCE is probably due to phenolic compounds present in the extract. The contemporary presence of antioxidant and antibacterial activities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity.