A transmission electron microscopy study of the diversity of Candida albicans cells induced by Euphorbia hirta L. leaf extract in vitro

Objective

To determine the major changes in the microstructure of Candida albicans (C. albicans) after treatment with Euphorbia hirta (E. hirta) L. leaf extract.

Methods

Transmission electron microscopy was used to study the ultrastructural changes caused by E. hirta extract on C. albicans cells at various exposure time.

Results

It was found that the main abnormalities were the alterations in morphology, lysis and complete collapse of the yeast cells after 36 h of exposure to the extract. Whereas the control cultures showed a typical morphology of Candida with a uniform central density, typically structured nucleus, and a cytoplasm with several elements of endomembrane system and enveloped by a regular, intact cell wall.

Conclusions

The significant antifungal activity shown by this methanol extract of E. hirta L. suggests its potential against infections caused by C. albicans. The extract may be developed as an anticandidal agent.     

Cytotoxicity and genotoxicity assessment of Euphorbia hirta in MCF-7 cell line model using comet assay

Objective

To evaluate the cytotoxicity and genotoxicity activity of Euphorbia hirta (E. hirta) in MCF-7 cell line model using comet assay.

Methods

The cytotoxicity of E. hirta extract was investigated by employing brine shrimp lethality assay and the genotoxicity of E. hirta was assessed by using Comet assay.

Results

Both toxicity tests exhibited significant toxicity result. In the comet assay, the E. hirta extract exhibited genotoxicity effects against MCF-7 DNA in a time-dependent manner by increasing mean percentage of DNA damage. The extract of E. hirta showed significant toxicity against brine shrimp with an LC₅₀ value of 620.382 µg/mL (24 h). Comparison with positive control potassium dichromate signifies that cytotoxicity exhibited by the methanol extract might have moderate activity.

Conclusion

The present work confirmed the cytotoxicity and genotoxicity of E. hirta. However, the observed toxicity of E. hirta extracts needs to be confirmed in additional studies.     

斑马鱼几种病原菌监测

目的对斑马鱼进行几种病原菌的流行病学调查,为后续相关标准的制定提供依据。方法基于细菌的形态学及生理生化特性为基础的传统方法,并与分子生物学方法相结合,最后分离株人工感染健康斑马鱼,观察实验组发病、死亡情况以判定其对斑马鱼的致病性强弱,从而了解影响斑马鱼健康的主要病原菌。结果在所有采样单位共检出3种病原菌,包括嗜水气单胞菌、温和气单胞菌和铜绿假单胞菌。嗜水气单胞菌普遍存在于大多数被检单位,且有较强的致病力。个别单位检出温和气单胞菌和铜绿假单胞菌。温和气单胞菌致病力稍弱;铜绿假单胞菌致病力最弱,感染斑马鱼无典型临床症状,无死亡。结论嗜水气单胞菌可能造成实验用鱼设施的污染,嗜水气单胞菌已证明可以感染人类,此类潜在的人-鱼感染途径应引起重视。由此建议,嗜水气单胞菌应成为重点监控的病原菌。     

Prevalence of Opportunistic Pathogens and Diversity of Microbial Communities in the Water System of a Pulmonary Hospital

Objective Our objective was to investigate the occurrence of opportunistic pathogens and characterize the bacterial community structures in the water system of a pulmonary hospital.Methods The water samples were collected from automatic and manual faucets in the consulting room, treatment room, dressing room, respiratory ward, and other non-medical rooms in three buildings of the hospital. Quantitative polymerase chain reaction was used to quantify the load of several waterborne opportunistic pathogens and related microorganisms, including Legionella spp.,Mycobacterium spp., and M. avium. Illumina sequencing targeting 16 S r RNA genes was performed to profile bacterial communities.Results The occurrence rates of Legionella spp., Mycobacterium spp., and M. avium were 100%, 100%,and 76%, respectively in all samples. Higher occurrence rates of M. avium were observed in the outpatient service building(building 1, 91.7%) and respiration department and wards(building 2, 80%)than in the office building(building 3), where no M. avium was found. M. avium were more abundant in automatic faucets(average 2.21 × 10~4 gene copies/L) than in manual faucets(average 1.03 × 10~4 gene copies/m L)(P 0.01). Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Acidobacteria were the dominant bacterial phyla. Disinfectant residuals, nitrate, and temperature were found to be the key environmental factors driving microbial community structure shifts in water systems.Conclusion This study revealed a high level of colonization of water faucets by opportunistic pathogens and provided insight into the characteristics of microbial communities in a hospital water system and approaches to reduce risks of microbial contamination.     

Detection and Identification of Six Foodbome Bacteria by Two-tube Multiplex Real Time PCR and Melting Curve Analysis

Objective This study is aimed to develop a two-tube melting curve-based multiplex real time PCR assay （MCMRT-PCR） for the simultaneous detection of six common foodborne pathogenic bacteria （diarrhoeagenic Escherichia coli, Salmonella, and 5higella in tube 1, Staphylococcus aureus, Vibrio parahaemolyticus, and Listeria monocytogenes in tube 2）. Methods A two-tube MCMRT-PCR assay was performed on 7900HT Fast Real-Time PCR System {Applied Biosystems, USA）. Amplification by PCR was optimized to obtain high efficiency. The sensitivity and specificity of assays were investigated. Results The detection limit of optimized MCMRT-PCR assay was 3.9x102 CFU/mLfor S. aureus, 4.4x102 CFU/mL for L. monocytogenes, 3.0x102 CFU/mL for Salmonella, 2.5x102 CFU/mL for Shigella, 2.1x102 CFU/mL for V. parahaemolyticus, and 1.2x102 CFU/mL for E. coll. The feasibility of MCMRT-PCR was further evaluated using artificially contaminated milk, the sensitivity was at the level of 10s CFU/mL. Conclusion A two-tube MCMRT-PCR assay using six primer sets was developed for detection of multiple pathogens. Our findings demonstrates that the proposed two-tube assay is reliable, useful and rapid for simultaneous detection of six foodborne pathogenic bacteria with an intended application in provincial Centers for Diseases Control and Prevention （CDC）.     

Subacute oral toxicity study of ethanolic leaves extracts of Strobilanthes crispus in rats

ObjectiveTo examine the oral toxicity of repeated dosing of Strobilanthes crispus (S. crispus) ethanol leaves extract on the liver and kidney functions in Sprague Dawley rats.MethodsYoung female rats aged between 8 and 12 week-old were randomly assigned into four groups with five animals each group (n=5). The first group served as control, while the second, third and fourth groups were orally treated with a single dose daily with 150 mg/kg, 300 mg/kg, and 600 mg/kg of S. crispus ethanol leaves extract for 14 d consecutively. Cage-side observation was conducted for first 4 h after each dosing. The body weight changes, food consumptions and water intake were also recorded. Serum biochemical parameters, i.e., aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine and urea were determined at Day 15. All results were expressed as mean±SD and analysed using Dunnett's test.ResultsIt was obtained that 14-day oral administration of S. crispus ethanol leaves extract did not cause any adverse effects or lethality to the female Sprague Dawley rats. No significant changes in serum biochemical parameters, relative organs weights, body weights, food intake and water consumptions were observed between the treatment groups and control.ConclusionsIn conclusion, 14-day oral administration of S. crispus ethanol leaves extract was safe to be consumed in female rats without affecting the liver and kidney functions.     

Analgesic,antibacterial and central nervous system depressant activities of Albizia procera leaves

ObjectiveTo ascertain analgesic, antibacterial and central nervous system (CNS) depressant activities of ethyl acetate, dichloromethane and carbon tetrachloride fractions of methanol extract of Albizia procera (A. procera) leaves.MethodsLeaves extracts of A. procera were tested for analgesic activity by acetic acid induced and formalin test method in mice. The in vitro antibacterial activity was performed by agar well diffusion method. CNS depressant activity was evaluated by hole cross and open field tests.ResultsAll the extracts at 200 mg/kg exhibited significant (P<0.01) analgesic activity in acetic acid induced and formalin tests method in mice. Analgesic activity of the ethyl acetate fraction was almost same like as standard drug indomethacin in acetic acid induced method. The CNS depressant activity of the extracts at 500 mg/kg was comparable to the positive control diazepam as determined by hole cross and open field test method. The extracts exhibited moderate antimicrobial activity against all the tested microorganisms (Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Esherichia coli, Shigella soneii, Shigella boydii) at concentration of 0.8 mg/disc. The measured diameter of zone of inhibition for the extracts was within the range of 7 to 12 mm which was less than the standard kanamycin (16-24 mm).ConclusionsIt is concluded that all the extracts possess potential analgesic and CNS depressants activity. This study also showed that different fractions of methanol extract could be potential sources of new antimicrobial agents.     

Antidiabetic and antihyperlipidaemic activity of ethanol extract of Melastoma malabathricum Linn. leaf in alloxan induced diabetic rats

ObjectiveTo evaluate the antidiabetic and antihyperlipidaemic effect of ethanol extract of Melastoma malabathricum (M. malabathricum) Linn. leaf in alloxan induced diabetic rats.MethodsDiabetes was induced in albino rats by administration of alloxan monohydrate (150 mg/kg i.p). the ethanol extracts of M. malabathricum at a dose of 150 and 300 mg/kg of body weight were administrated at a single dose per day to diabetes induced rats for a period of 14 d. The effect of ethanol extract of M. malabathricum leaf extract on blood glucose, plasma insulin, creatinine, glycosylated haemoglobin, urea serum lipid profile [total cholesterol, triglycerides, low density lipoprotein-cholesterol, very low density lipoprotein-cholesterol, high density lipoprotein-cholesterol and phospholipid, serum protein, albumin, globulin, serum enzymes (serum glutamate pyruvate transaminases), serum glutamate oxaloacetate transaminases, and alkaline phosphatase] were measured in the diabetic rats.ResultsIn the acute toxicity study, ethanol extract of M. malabathricum leaf was non-toxic at 2 000 mg/kg in rats. The increased body weight, decreased blood glucose, glycosylated haemoglobin and other biochemical parameters level were observed in diabetic rats treated with both doses of ethanol extract of M. malabathricum leaf compared to diabetic control rats. In diabetic rats, ethanol extract of M. malabathricum leaf administration, altered lipid profiles were reversed to near normal than diabetic control rats.ConclusionsEthanol extract of M. malabathricum leaf possesses significant antidiabetic and antihyperlipidaemic activity in diabetic rats.     

Antioxidant,antimicrobial, cytotoxic and analgesic activities of ethanolic extract of Mentha arvensis L.

ObjectiveTo investigate potential antioxidant, antimicrobial, cytotoxic and analgesic activities of ethanolic extract of Mentha arvensis L. in different in vivo and in vitro experimental models.MethodsIn vitro DPPH radical scavenging assay was used to evaluate the antioxidant activity of the plant extract. In vivo analgesic activity was carried out by acetic acid-induced writhing test in Swiss albino mice. All studies in mice were undertaken at the doses of 250 and 500 mg/kg body weight. Antibacterial activity was studied by disk diffusion assay against some Gram-positive and Gram-negative bacterial strains. Brine shrimp lethality assay was used to investigate cytotoxicity effects of the plant extract.ResultsThe extract showed free radical scavenging activity in the DPPH assay (IC₅₀∼41 μg/mL) compared to the standard antioxidant ascorbic acid (IC₅₀∼19 μg/mL). The extract also produced prominent antimicrobial activity against Salmonella typhi, Salmonella paratyphi, Shigella boydii, Streptococcus pyogenes and Streptococcus aureus compared to standard drug kanamycin at the dose of 30 μg/disc. The extract exhibited lethality against the brine shrimp nauplii with the LC₅₀ values of 40 μg/mL, and also 90% mortality (LC₉₀) value was found to be 160 μg/mL. In analgesic test, the extract demonstrated statistically significant (P<0.01) analgesic effect in acetic acid induced writhing in white albino mice at both dose levels.ConclusionsThese results suggest that the ethanolic extract of Mentha arvensis L. has potential antioxidant, antibacterial, cytotoxic and analgesic activities that support the ethnopharmacological uses of this plant.     

Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

ObjectiveTo investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis.MethodsAgar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts.ResultsMethanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth.ConclusionsThe efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.     

Studies on the antibacterial activity of Khaya senegalensis [(Desr.) A. Juss)] stem bark extract on Salmonella enterica subsp. enterica serovar Typhi [(ex Kauffmann and Edwards) Le Minor and Popoff]

ObjectiveTo study the phytochemical screening and antibacterial activity of the stem bark extracts of Khaya senegalensis (K. senegalensis) against Salmonella enterica subsp. enterica serovar Typhi.MethodsThe plant components were extracted using methanol, ethanol and water. The phytochemical screening of the stem bark extracts were carried out using a standard method. The antibacterial assay of the stem bark extracts against Salmonella Typhi (S. Typhi) using the agar well diffusion method with different concentrations of 50, 100, 200, 400 and 500 mg/mL and the corresponding concentrations of the control was carried out and the result compared with a standard antibiotic, amoxicillin as the control.ResultsThe results obtained from the phytochemical screening of the three plant bark extracts of K. senegalensis showed 10 plant secondary metabolites including saponins, tannins, reducing sugars, aldehyde, phlobatannins, flavonoids, terpenoids, alkaloids, cardiac glycoside and anthroquinones. The ethanol and aqueous extracts showed antibacterial activities against S. Typhi at concentration of 50 mg/mL with the zone diameter of inhibition (ZDI) of 14 mm and 15 mm respectively. The ethanol and aqueous extracts also showed zone diameter of inhibition of 23 mm and 25 mm respectively at 250 mg/mL and 27 mm each at 500 mg/mL. The ethanol and aqueous stem bark extracts gave the highest ZDI at 500 mg/mL while 100 mg/mL gave the least ZDI for ethanol extract and 50 mg/mL for the aqueous extract. This was followed by 400 mg/mL that gave 24 mm ZDI of the aqueous extract and 27 mm of the ethanol extract. The methanol extract showed intermediate susceptibility evidenced by ZDI of 10 mm at 100 mg/mL concentration. The methanol extract also showed antibacterial activity of 24 mm ZDI against the test organism at a higher concentration of 250 mg/mL and 26 mm at 500 mg/mL concentration. The methanol, ethanol and aqueous extracts displayed antibacterial activities against S. Typhi with a statistical significant difference at (P≤0.05). The extracts compared favourably with the standard antibiotic, the control. The minimum inhibitory concentration of the extracts was 250, 200, 200 and 100 mg/mL for methanol, ethanol, aqueous extracts and amoxicillin (control) respectively. The minimum lethal concentration of the extracts was 250, 250, 400 and 200 mg/mL for methanol, ethanol, aqueous extracts and control respectively.ConclusionsThe antibacterial properties of K. senegalensis stem bark extract can be harnessed for the production of new antibiotics or the enhancement of already existing antibiotics.     

Genetic Diversity,Antibiotic Resistance,and Pathogenicity of Aeromonas Species from Food Products in Shanghai,China

ObjectiveAeromonas has recently been recognized as an emerging human pathogen. Aeromonas-associated diarrhea is a phenomenon occurring worldwide. This study was designed to determine the prevalence, genetic diversity, antibiotic resistance, and pathogenicity of Aeromonas strains isolated from food products in Shanghai.MethodsAeromonas isolates (n = 79) collected from food samples were analyzed using concatenated gyrB-cpn60 sequencing. The antibiotic resistance of these isolates was determined using antimicrobial susceptibility testing. Pathogenicity was assessed using β-hemolytic, extracellular protease, virulence gene detection, C. elegans liquid toxicity (LT), and cytotoxicity assays.ResultsEight different species were identified among the 79 isolates. The most prevalent Aeromonas species were A. veronii [62 (78.5%)], A. caviae [6 (7.6%)], A. dhakensis [3 (3.8%)], and A. salmonicida [3 (3.8%)]. The Aeromonas isolates were divided into 73 sequence types (STs), of which 65 were novel. The isolates were hemolytic (45.6%) and protease-positive (81.0%). The most prevalent virulence genes were act (73.4%), fla (69.6%), aexT (36.7%), and ascV (30.4%). The results of C. elegans LT and cytotoxicity assays revealed that A. dhakensis and A. hydrophila were more virulent than A. veronii, A. caviae, and A. bivalvium. Antibiotic resistance genes [tetE, blaTEM, tetA, qnrS, aac(6)-Ib, mcr-1, and mcr-3] were detected in the isolates. The multidrug-resistance rate of the Aeromonas isolates was 11.4%, and 93.7% of the Aeromonas isolates were resistant to cefazolin.ConclusionThe taxonomy, antibiotic resistance, and pathogenicity of different Aeromonas species varied. The Aeromonas isolates A. dhakensis and A. hydrophila were highly pathogenic, indicating that food-derived Aeromonas isolates are potential risks for public health and food safety. The monitoring of food quality and safety will result in better prevention and treatment strategies to control diarrhea illnesses in China.     

Phytochemical screening and anticonvulsant studies of ethyl acetate fraction of Globimetula braunii on laboratory animals

ObjectiveTo investigate the phytochemical properties and the anticonvulsant potential of the ethyl acetate soluble fraction of ethanol leaf extract of Globimetula braunii, a plant used in ethnomedicine for the treatment of epilepsy.MethodsThe phytochemical screening was carried out using standard protocol while the anticonvulsant activity was studied using maximal electroshock test in chicks, pentylenetetrazole and 4-aminopyridine-induced seizures in mice.ResultsThe preliminary phytochemical screening carried out on the crude ethanol extract revealed the presence of saponins, carbohydrates, flavonoids, tannins, anthraquinones and steroids. Similarly, tannins, flavonoids and steroids/terpenes were found to be present in the ethyl acetate fraction. In the pharmacological screening, 150 mg/kg of the fraction protected 83.33% of animals against pentylenetetrazole-induced seizure in mice whereas sodium valproate a standard anti-epileptic drug offered 100% protection. In the 4-aminopyridine-induced seizure model, the fraction produced a significant (P<0.05) increase in the mean onset of seizure in unprotected animals. The fraction did not exhibit a significant activity against maximal electroshock convulsion. The median lethal dose of the fraction was found to be 1261.91 mg/kg.ConclusionsThese results suggest that the ethyl acetate fraction of Globimetula braunii leaves extract possesses psychoactive compound that may be useful in the management of petit mal epilepsy and lend credence to the ethnomedical use of the plant in the management of epilepsy.     

Salvia fruticosa reduces intrinsic cellular and H2O2-induced DNA oxidation in HEK 293 cells; assessment using flow cytometry

ObjectiveTo investigate the role of water-soluble extract of Salvia fruticosa (Greek sage) (S. fruticosa) leaves in reducing both intrinsic cellular and H₂O₂-induced DNA oxidation in cultured human embryonic kidney 293 cells. S. fruticosa, native to the Eastern-Mediterranean basin, is widely used as a medicinal herb for treatment of various diseases.MethodsDried leaves of S. fruticosa were extracted in phosphate buffer saline and purified using both vacuum and high pressure filtrations. Each mL of the preparation contained (7.1×1.0) mg of extract. HEK-293 cells were incubated in one set with S. fruticosa extract in the presence of 0.1 mmol/L H₂O₂, and in the other set with the addition of the extract alone. The DNA oxidation was measured using fluorescence upon fluorescein isothiocyanate derivatization of 8-oxoguanine moieties. The fluorescence was measured using flow cytometry technique.ResultsCells incubated 3 h with 150 μL extract and exposed to 0.1 mmol/L H₂O₂ showed lower intensity of fluorescence, and thus lower DNA oxidation. Moreover, cells incubated 3 h with 100 μL of the extract showed lower intensity of fluorescence, and thus lower intrinsic cellular DNA oxidation compared to control (without S. fruticosa).ConclusionsThe results from this study suggest that the water-soluble extract of S. fruticosa leaves protects against both H₂O₂-induced and intrinsic cellular DNA oxidation in human embryonic kidney 293 cells.     

Susceptibility of microorganism to selected medicinal plants in Bangladesh

ObjectiveTo analyze in-vitro antimicrobial activities of some ethno-pharmacologically significant medicinal plants (methanol extract) against the pathogenic microorganisms (Escherichia coli, Salmonella spp., Bacillus cereus, Staphylococcus aureus, Aspergillus niger and Candida albicans).MethodsThe disc diffusion method was applied for antibacterial test and the poisoned food technique was applied for antifungal test.ResultsThe methanol extract of Terminalia chebula (bark), Phyllanthus acidus (fruits), Sarcochlamys pulcherrima (leaves) and Abelmoschus esculentus (fruits) had significant in vitro antibacterial activity angainst the entire test samples in comparison to standard drug ciprofloxacin. Most of the plant extracts showed low activity against Gram negative bacteria while potential activity against Gram positive bacteria. The antifungal activities of methanol extracts of these plants and standard drug griseofulvin were determined against two pathogenic fungi, and Polygonum lapathifolium (leaves) and Cinnamomum tamala (leaves) showed maximum activity, while Erioglossum rubiginosum (leaves) showed no antifungal activity.ConclusionsFurther chemical and pharmacological investigations are required to identify and isolate chemical constituents responsible for these potential bioactivities and thus to determine their full spectrum of efficacy.     

Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

Objective

To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet (Z. zerumbet) (L.) Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi.

Methods

The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol (4.0 L) after concentration. The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract (15.0 g), petroleum ether fraction (6.6 g) and chloroform soluble fraction (5.0 g). The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method. Commercially available kanamycin (30 µg/disc) was used as standard disc and blank discs impregnated with the respective solvents were used as negative control.

Results

At a concentration of 400 µg/disc, all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm. Among the tested samples, the crude ethanol extract showed the highest activity against Vibrio parahemolyticus (V. parahemolyticus). The minimum inhibitory concentration (MIC) of the crude ethanol extract and its fractions were within the value of 128-256 µg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V. parahemolyticus (128 µg/mL).

Conclusions

It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L).     

GC-MS analysis,determination of total phenolics,flavonoid content and free radical scavenging activities of various crude extracts of Moringa peregrina (Forssk.) Fiori leaves

ObjectiveTo perform phytochemical screening, estimate total phenolics, flavonoids and to evaluate antioxidant potential of Moringa peregrina (M. peregrina) leaves.MethodsThe dried powdered leaves of M. peregrina (150 g) were extracted exhaustively by Soxhlet with ethanol and then fractionated into hexane, chloroform, ethy alacetate and methanol. All the prepared extracts were also analyzed by gas chromatography-mass spectrometry to identify and characterize the chemical compounds present in the crude extracts. Folin- Ciocalteu reagent and aluminium chloride colorimetric methods were used to estimate total phenolic and flavonoid content of extracts. Hydrogen peroxide and 1,1 diphenyl -2-picrylhydrazyl were used to determine in vitro antioxidant activity.ResultsPhytochemical analysis of ethanol extract showed presence of major classes of phytochemicals. Gas chromatography-mass spectrometry results revealed presence of 19 phytoconstituents in hexane extract, 6 in ethyl acetate and 7 compounds in methanolic extract. Methanol extract was found to contain the highest phenolic content and flavonoids. In vitro antioxidant activities of all crude extracts were significant and comparable with the standard ascorbic acid.ConclusionsResults of this study show that the leaves of M. peregrina are the rich source of phenolic compounds that can play an important role in preventing the progression of many diseases.     

Multi-drug resistance and characteristic of integrons in Shigella spp. isolated from China

Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains (83 S. flexneri and 7 S. sonnei) were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them. Results High prevalence of multi‐drug resistance (95.6%) was identified. Of the isolates 79 (87.8%) carri...     

Multi–antibiotic resistant bacteria in frozen food (ready to cook food) of animal origin sold in Dhaka,Bangladesh

ObjectiveTo investigate the bacterial load and antibiotic resistance pattern of bacterial isolates obtained from (ready to cook) frozen food samples of animal origin in Dhaka, Bangladesh.MethodsA total of 20 samples of frozen ready to cook food of animal origin were purchased from different separate grocery stores in Dhaka, Bangladesh. Bacteria were isolated and identified based on the basis of biochemical properties.ResultsA total of 57 isolates has been isolated from 20 samples, of them 35.08% were Gram positive and 64.92% were Gram negative organisms. Highest percentages of isolated organisms were Staphylococcocus spp. (24.56%), Alcaligene spp. (17.54%), Klebshiella spp. (12.28%) and the lowest percentages of organisms were Enterococcus spp., Actinobacillus spp. and Proteus spp. Antibiogram results clearly showed that levofloxacin and imipenem were the most effective drug against the isolates. The less effective antibiotics were chloramphenicol and nalidixic acid and resistance was highest against ciprofloxacin. The most contaminated food was chicken nuggets.ConclusionsThis type of frozen food contaminated with multi-antibiotic resistant microorganisms can be potential vehicles for transmitting food-borne diseases.     

Evaluation of aqueous and ethanol extract of bioactive medicinal plant,Cassia didymobotrya (Fresenius) Irwin & Barneby against immature stages of filarial vector,Culex quinquefasciatus Say (Diptera: Culicidae)

Objective

To evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus.

Methods

The mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol. The wide range concentration tested in the present study was 10 000, 1 000, 100, 10 and 1 mg/L and narrow range concentration was 50, 100, 150, 200 and 250 mg/L.

Results

2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100% mortality. Remaining stages such as 3rd, 4th and pupa, 100% mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period. In aqueous extract all the stages 100% mortality was recorded at 1 000 mg/L and above concentration. In narrow range concentration 2nd instar larvae 100% mortality was observed at 150 mg/L and above concentration of ethanol extract. The remaining stages 100% mortality was recorded at 250 mg/L. In aqueous extract all the tested immature stages 100% mortality was observed at 250 mg/L concentration after 24 h exposure period. The results clearly indicate that the rate of mortality was based dose of the plant extract and stage of the mosquitoes.

Conclusions

From this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus. The isolation of bioactive molecules and development of simple formulation technique is important for large scale implementation.