Green synthesis-assisted copper nanoparticles using Aegle marmelos leaves extract: physical, optical, and antimicrobial properties.

In the present report, Aegle marmelos leaf powder was used to synthesize copper nanoparticles (CuNPs) using a simple and cost-effective method. A. marmelos leaves have various medicinal uses including for the treatment of diarrhoea, constipation, diabetes, cholera, skin diseases, earache, blood purification, heart problems, and so on. The plant biomolecules induce the reduction of Cu2+ ions to CuNPs and also act as a capping and stabilizing agent. The formation of CuNPs was confirmed using photoluminescence (PL) excitation and emission spectra on a Shimadzu RF-5301 PC spectrofluorophotometer and the absorbance spectra of a UV-visible spectrophotometer at different stages during the synthesis process. In addition, other properties of synthesized CuNPs were also investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy techniques. The average size of the synthesized CuNPs was in the range 20-40 nm. Furthermore, the synthesized NPs were also considered for an antimicrobial study against Gram-positive Staphylococcus aureus and Proteus, and Gram-negative Escherichia coli and Salmonella spp. using the agar well diffusion method. The zone of inhibition against the Gram-positive bacteria was greater than the zone of inhibition against the Gram-negative bacteria. These investigation results suggest that synthesized NPs are promising nanomaterials for use as antimicrobial agents.

Interactions of Chitosan-coated Green Synthesized Silver Nanoparticles using Mentha spicata and Standard Antibiotics against Bacterial Pathogens.

BACKGROUND: Infectious diseases are caused by various multidrug-resistant pathogenic bacteria and in recent scenarios, nanoparticles have been used as innovative antimicrobial agents. AIMS: This current research aimed to evaluate the bactericidal effect of chitosan-coated green synthesized silver nanoparticles using aqueous extract of Mentha spicata (MSaqu) against bacterial pathogens, i.e., Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, and Streptococcus pyogenes. METHODS: Synthesis and characterization of silver nanoparticles (MSAgNPs) were carried out via atomic absorption spectrometer and Fourier-transform infrared spectroscopy. Agar well and agar disc diffusion methods were used to assess the antibacterial and synergistic effect of chitosanmediated biogenic silver nanoparticles and standard antibiotics. Three types of interactions, i.e., antagonistic (↓), synergistic (↑), and additive (¥) were observed. RESULTS: Synergistic effect was recorded against Pseudomonas aeruginosa (8.5±0.25 mm↑), Serratia marcescens (19.0±1.0 mm↑), and Klebsiela pneumonia (8.5±0.25 mm↑), an additive effect was exhibited by Escherichia coli (9.0±0.0 mm¥), Streptococcus pyogenes (10.0±0.0 mm¥), and Staphylococcus aureus (7.5±0.25 mm↓) and they showed antagonistic effects when chitosan-coated silver nanoparticles (CLMSAgNPs) were applied compared to chitosan, MSaqu, and MSAgNPs. Interesting antibacterial results were recorded when chitosan-coated Mentha spicata extract and silver nanoparticles were applied along with antibiotics. The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + K were recorded against E. coli (14.5±0.25 mm). The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + AML were recorded against E. coli (5.5±0.0 mm), S. pyogenes (10.0±0.0 mm), K. pneumonia (5.5±0.0 mm), and S. aureus (4.0±0.0 mm). The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + NOR were recorded against E. coli (16.0±0.0 mm), P. aeruginosa (19.0±0.0 mm), S. marcescens (19.5±0.25 mm), S. pyogenes (11.5.0±0.25 mm), K. pneumonia (23.0±0.0 mm), and S. aureus (8.5±0.25 mm). CONCLUSION: Current findings concluded that chitosan-coated biogenic silver nanoparticles have potential bactericidal effects against infectious pathogens and could be used as forthcoming antibacterial agents.

Evaluation of antibacterial activity of vitamin C against human bacterial pathogens / Avaliação da atividade antibacteriana da vitamina C contra patógenos bacterianos humanos

Now a day’s multidrug resistance phenomenon has become the main cause for concern and there has been an inadequate achievement in the development of novel antibiotics to treat the bacterial infections. Therefore, there is an unmet need to search for novel adjuvant. Vitamin C is one such promising adjuvant. The present study was aimed to elucidate the antibacterial effect of vitamin C at various temperatures (4°C, 37°C and 50°C) and pH (3, 8, and 11), against Gram-positive and Gram-negative bacteria at various concentrations (5-20 mg/ml) through agar well diffusion method. Growth inhibition of all bacterial strains by vitamin C was concentration-dependent. Vitamin C significantly inhibited the growth of Gram-positive bacteria: Bacillus licheniformis (25.3 ± 0.9 mm), Staphylococcus aureus (22.0 ± 0.6 mm), Bacillus subtilis (19.3 ± 0.3 mm) and Gram-negative bacteria: Proteus mirabilis (27.67 ± 0.882 mm), Klebsiella pneumoniae (21.33±0.9 mm), Pseudomonas aeruginosa (18.0 ± 1.5 mm) and Escherichia coli (18.3 ± 0.3 mm). The stability of vitamin C was observed at various pH values and various temperatures. Vitamin C showed significant antibacterial activity at acidic pH against all bacterial strains. Vitamin C remained the stable at different temperatures. It was concluded that vitamin C is an effective and safe antibacterial agent that can be used in the future as an adjunct treatment option to combat infections in humans.

Agora, a resistência antimicrobiana de um dia em patógenos aos antibióticos tornou-se a principal causa de preocupação e houve uma realização inadequada no desenvolvimento de novos antibióticos para tratar infecções bacterianas. Portanto, há uma necessidade de pesquisar um novo adjuvante, e a vitamina C é um desses adjuvantes promissores. O objetivo do presente estudo foi elucidar o efeito antibacteriano da vitamina C em diferentes temperaturas (4 °C, 37 °C e 50 °C) e pH (3, 8 e 11), contra Gram-positivos e Gram-cepas bacterianas negativas em várias concentrações (5-20 mg / ml) através do método de difusão em ágar bem. A inibição do crescimento de todas as cepas bacterianas pela vitamina C era dependente da concentração. A vitamina C inibiu significativamente o crescimento de bactérias Gram-positivas: Bacillus licheniformis (25,3 ± 0,9 mm), Staphylococcus aureus (22,0 ± 0,6 mm), Bacillus subtilis (19,3 ± 0,3 mm) e bactérias Gram- negativas: Proteus mirabilis (27,7 ± 0,9 mm), Klebsiella pneumoniae (21,3 ± 0,9 mm), Pseudomonas aeruginosa (18,0 ± 1,5 mm) e Escherichia coli (18,3 ± 0,3 mm). A estabilidade da vitamina C foi observada em vários valores de pH e várias temperaturas. A vitamina C mostrou atividade antibacteriana significativa em pH ácido contra todas as cepas bacterianas. A estabilidade da vitamina C permaneceu nas mesmas diferentes temperaturas (4 °C, 37 °C e 50 °C). Concluímos que a vitamina C é um agente antibacteriano eficaz e seguro que pode ser usado no futuro como uma opção de tratamento auxiliar para combater infecções em humanos, pois pode apoiar o sistema imunológico diretamente.

Evaluation of antibacterial activity of vitamin C against human bacterial pathogens

Abstract Now a days multidrug resistance phenomenon has become the main cause for concern and there has been an inadequate achievement in the development of novel antibiotics to treat the bacterial infections. Therefore, there is an unmet need to search for novel adjuvant. Vitamin C is one such promising adjuvant. The present study was aimed to elucidate the antibacterial effect of vitamin C at various temperatures (4°C, 37°C and 50°C) and pH (3, 8, and 11), against Gram-positive and Gram-negative bacteria at various concentrations (5-20 mg/ml) through agar well diffusion method. Growth inhibition of all bacterial strains by vitamin C was concentration-dependent. Vitamin C significantly inhibited the growth of Gram-positive bacteria: Bacillus licheniformis (25.3 ± 0.9 mm), Staphylococcus aureus (22.0 ± 0.6 mm), Bacillus subtilis (19.3 ± 0.3 mm) and Gram-negative bacteria: Proteus mirabilis (27.67 ± 0.882 mm), Klebsiella pneumoniae (21.33±0.9 mm), Pseudomonas aeruginosa (18.0 ± 1.5 mm) and Escherichia coli (18.3 ± 0.3 mm). The stability of vitamin C was observed at various pH values and various temperatures. Vitamin C showed significant antibacterial activity at acidic pH against all bacterial strains. Vitamin C remained the stable at different temperatures. It was concluded that vitamin C is an effective and safe antibacterial agent that can be used in the future as an adjunct treatment option to combat infections in humans.

Resumo Agora, a resistência antimicrobiana de um dia em patógenos aos antibióticos tornou-se a principal causa de preocupação e houve uma realização inadequada no desenvolvimento de novos antibióticos para tratar infecções bacterianas. Portanto, há uma necessidade de pesquisar um novo adjuvante, e a vitamina C é um desses adjuvantes promissores. O objetivo do presente estudo foi elucidar o efeito antibacteriano da vitamina C em diferentes temperaturas (4 °C, 37 °C e 50 °C) e pH (3, 8 e 11), contra Gram-positivos e Gram-cepas bacterianas negativas em várias concentrações (5-20 mg / ml) através do método de difusão em ágar bem. A inibição do crescimento de todas as cepas bacterianas pela vitamina C era dependente da concentração. A vitamina C inibiu significativamente o crescimento de bactérias Gram-positivas: Bacillus licheniformis (25,3 ± 0,9 mm), Staphylococcus aureus (22,0 ± 0,6 mm), Bacillus subtilis (19,3 ± 0,3 mm) e bactérias Gram- negativas: Proteus mirabilis (27,7 ± 0,9 mm), Klebsiella pneumoniae (21,3 ± 0,9 mm), Pseudomonas aeruginosa (18,0 ± 1,5 mm) e Escherichia coli (18,3 ± 0,3 mm). A estabilidade da vitamina C foi observada em vários valores de pH e várias temperaturas. A vitamina C mostrou atividade antibacteriana significativa em pH ácido contra todas as cepas bacterianas. A estabilidade da vitamina C permaneceu nas mesmas diferentes temperaturas (4 °C, 37 °C e 50 °C). Concluímos que a vitamina C é um agente antibacteriano eficaz e seguro que pode ser usado no futuro como uma opção de tratamento auxiliar para combater infecções em humanos, pois pode apoiar o sistema imunológico diretamente.

Effect of aqueous and organic solvent extraction on in-vitro antimicrobial activity of two varieties of fresh ginger (Zingiber officinale) and garlic (Allium sativum).

The current state of antimicrobial resistance to synthetic antimicrobial drugs has led to renewed interest in natural antimicrobial compounds. Antimicrobial activity of extracts of (local and hybrid) ginger and garlic was investigated using the agar well diffusion method against Staphylococcus aureus, Escherichia coli and Candida albicans. Aqueous and organic solvent extracts of both varieties of ginger and garlic exhibited varied and concentration-dependant antimicrobial activity. Inhibition zones at 25 mg/mL varied significantly against the microorganisms, being highest on C. albicans; 18.00 ± 2.00 to 30.67 ± 1.16 mm for acetone extracts and raw juice of hybrid ginger and 19.67 ± 1.16 to 30.33 ± 1.53 mm for methanol and raw extracts of local garlic respectively. Minimum Inhibitory Concentration ranged from 2.5 to 10 mg/mL in garlic extracts. The study concluded that both varieties of ginger and garlic possess antimicrobial substances, though ginger is more potent as antifungal agent.

Biogenic Synthesis, Characterization and Antibacterial Properties of Silver Nanoparticles against Human Pathogens.

Biogenic synthesis of silver nanoparticles (AgNPs) is more eco-friendly and cost-effective approach as compared to the conventional chemical synthesis. Biologically synthesized AgNPs have been proved as therapeutically effective and valuable compounds. In this study, the four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the biogenic synthesis of AgNPs. Agar well diffusion assay revealed to determine the antibacterial activity of all biogenically synthesized AGNPs showed that P. aeruginosa AgNPs possessed significantly high (p < 0.05) antibacterial potential against all tested isolates. The one-way ANOVA test showed that that P. aeruginosa AgNPs showed significantly (p < 0.05) larger zones of inhibition (ZOI: 19 to 22 mm) compared to the positive control (rifampicin: 50 µg/mL) while no ZOI was observed against negative control (Dimethyl sulfoxide: DMSO). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) concentration against four test strains also showed that among all biogenically synthesized NPs, P. aeruginosa AgNPs showed effective MIC (3.3-3.6 µg/mL) and MBC (4.3-4.6 µg/mL). Hence, P. aeruginosa AGNPs were characterized using visual UV vis-spectroscopy, X-ray diffractometer (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The formation of peak around 430 nm indicated the formation of AgNPs while the FTIR confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). SEM revealed that the NPs were of approximately 40 nm. Overall, this study suggested that the biogenically synthesized nanoparticles could be utilized as effective antimicrobial agents for effective disease control.

Hydrogel composite containing azelaic acid and tea tree essential oil as a therapeutic strategy for Propionibacterium and testosterone-induced acne.

Azelaic acid (AzA) is a USFDA bioactive prescribed against acne vulgaris. It possesses delivery challenges like poor aqueous solubility, low skin-penetrability, and dose-dependent side effects, which could be overcome by its synergistic combination with tea tree oil (TTO) as a microemulsion (ME)-based hydrogel composite. AzA-TTO ME was prepared to employ pseudo-ternary phase diagram construction. The best AzA-TTO ME was of uniform size (polydispersity index < 0.7), nano-range (~357.4 ± 2% nm), transmittance (> 90%), and negative zeta potential (-1.42 ± 0.25% mV) values. ME hydrogel composite with optimum rheological and textural attributes showed better permeation, retention, and skin-compliant characteristics, vis-a-vis marketed formulation (Aziderm™) when evaluated in Wistar rat skin. In vitro antibacterial efficacy in bacterial strains, i.e., Staphylococcus aureus, Propionibacterium acne, and Staphylococcus epidermidis, was evaluated employing agar well plate diffusion and broth dilution assay. ME hydrogel has shown an increase in zone of inhibition by two folds and a decrease in minimum inhibitory concentration (MIC) by eightfold against P. acnes vis-a-vis AzA. Finally, ME hydrogel composite exhibited a better reduction in the papule density (93.75 ± 1.64%) in comparison to Aziderm™ 72.69 ± 4.67%) on acne as developed in rats by inducing testosterone. Thus, the developed AzA-TTO ME hydrogel composite promises an efficacious and comparatively safer drug delivery system for the topical therapy of acne vulgaris.

Azelaic acid and Melaleuca alternifolia essential oil co-loaded vesicular carrier for combinational therapy of acne.

Aim: Azelaic acid (AzA), a comedolytic, antibacterial, anti-inflammatory anti-melanogenic agent, prescribed against acne vulgaris is safe on skin. Its combination with another widely used anti-acne agent, tea tree oil (EO) whose delivery is limited by volatility, instability and lipophilicity constraints was attempted. Method: Solvent injection was used to prepare AzA-EO integrated ethosomes. Result: Ethosomes were transformed into carbopol hydrogel, which exhibited pseudo-plastic properties with appreciable firmness, work of shear, stickiness and work of adhesion. The hydrogel showed better permeation and retention characteristics vis-a-vis commercial formulation (AzidermTM), when evaluated in Wistar rat skin. Further, ethosome hydrogel composite was better tolerated with no side effects. Conclusion: The findings suggests that the aforementioned strategy could be a potential treatment used for acne management.

Basic Antibacterial Assay to Screen for Bacteriocinogenic Lactic Acid Bacteria and to Elementarily Characterize Their Bacteriocins.

Bacteriocins ribosomally produced by lactic acid bacteria are antibacterial peptides expected to be used as a safe biopreservative and a fermentation controller in food industry. The modified agar-well diffusion method is most frequently used for antibacterial activity assay to screen for potentially bacteriocin-producing strains and to elementarily characterize their bacteriocins and the relatives. Here, I describe procedure of the modified agar-well diffusion assay in the details.

Evaluation of In-vitro Antimicrobial Potential of Daphne retusa Hemsl. Against Human Pathogenic Bacteria and Fungi.

BACKGROUND: Antimicrobial drug resistance is an emerging problem, which leads to a failure in the control of infectious diseases thereby, adversely affecting patient care and reducing effective management of infectious diseases globally. Thus, search for new and more effective alternatives is needed. Daphne retusa Hemsl. (Daphne) has medicinal values and is reported to be widely used in curing a variety of human ailments. OBJECTIVE: Current study assesses in-vitro antimicrobial activity of the crude extract of D.retusa (whole plant) and its derived fractions against clinically isolated human pathogenic bacteria and fungi. MATERIALS AND METHODS: Whole plant of D.retusa was powder dried and then extracted with methanol (E1). The resultant was fractionated to give Chloroform fraction (E2), Butanol fraction (E3) and Ethyl acetate fraction (E4). The crude extract and derived fractions were assessed for antimicrobial and antifungal activity by using agar well diffusion method and their MICs were found following Clinical and Laboratory Standard Institute (CLSI) guidelines. RESULT: Our study shows that D.retusa has very good inhibitory action against different bacterial and fungal strains. All of the extracts were active against almost every microorganism used in the study. E2 has the maximum percent of inhibition against bacterial growth while E1 has themaximum percent of inhibition against fungal growth. Streptococcus pneumonia was the most susceptible bacteria while among fungi, Gongronella butleri showed highest susceptibility. CONCLUSION: Results justify the use of D. retusa in the treatment of microbial infections. For the development of a novel antibiotic, the crude extract and its derived fractions need further exploration; with emphasis to isolate and identify the active constituents that are responsible for antibacterial and antifungal activity.

Evaluation of Antibacterial Activity of Three Selected Fruit Juices on Clinical Endodontic Bacterial Strains.

INTRODUCTION: The increasing problem of antibiotic drug resistance by pathogenic microorganisms in the past few decades has recently led to the continuous exploration of natural plant products for new antibiotic agents. Many consumable food materials have good as well as their bad effects, good effect includes their antibacterial effects on different microorganisms present in the oral cavity. Recently, natural products have been evaluated as source of antimicrobial agent with efficacies against a variety of microorganisms. METHODOLOGY: The present study describes the antibacterial activity of three selected fruit juices (Apple, Pomegranate and Grape) on endodontic bacterial strains. Antimicrobial activity of fruit juices were tested by wel l diffusion assay by an inhibition zone surrounding the well. The aim of the study was to evaluate the antibacterial activity of three fruit juises on different endodontic strains. RESULT: Agar well diffusion method was adopted for determining antibacterial potency. Antibacterial activity present on the plates was indicated by an inhibition zone surrounding the well containing the fruit juice. The zone of inhibition was measured by measuring scale in millimeter. Comparision between antibacterial efficacy of all three fruit juices against Enterococcus feacalis and Streptococcus mutans was observed with significant value of P ≤ 0.05. CONCLUSION: The results obtained in this study clearly demonstrated a significant antimicrobial effect of apple fruit juice against Enterococcus fecalis and Streptococcus mutans. However, preclinical and clinical trials are needed to evaluate biocompatibility & safety before apple can conclusively be recommended in endodontic therapy, but in vitro observation of apple effectiveness appears promising.

Antibacterial activity of actinomycetes isolated from different soil samples of Sheopur (A city of central India).

The main objective of the present study was isolation, purification, and characterization of actinomycetes from soil samples, having antimicrobial activity against 12 selected pathogenic strains. Soils samples were taken from different niche habitats of Sheopur district, Madhya Pradesh, India. These samples were serially diluted and plated on actinomycete isolation agar media. Potential colonies were screened, purified, and stored in glycerol stock. Isolates were morphologically and biochemically characterized. These isolates were subjected to extraction for production of the antibacterial compound. Antibacterial activity and Minimum Inhibitory Concentration (MIC) of the purified extract of isolates were evaluated. Totally 31 actinomycete isolates were tested for antagonistic activity against 12 pathogenic microorganisms. Isolates AS14, AS27, and AS28 were highly active, while AS1 showed less activity against the pathogenic microorganisms. Isolate AS7 exhibited the highest antagonistic activity against Bacillus cereus (24 mm) and AS16 showed the highest activity against Enterococcus faecalis (21 mm). MIC was also determined for actinomycete isolates against all the tested microorganisms. MIC of actinomycete isolates was found to be 2.5 mg/ml against Shigella dysenteriae, Vancomycin-resistant enterococci, and Klebsiella pneumoniae, and was 1.25 mg/ml for Staphylococcus saprophyticus, Streptococcus pyogenes, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus, Bacillus cereus, Staphylococcus xylosus, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Staphylococcus aureus. All actinomycetes isolates showed antibacterial activity against S. aureus, while they showed less activity against S. dysenteriae. These isolates had antibacterial activity and could be used in the development of new antibiotics for pharmaceutical or agricultural purposes.

Isolation and characterization of potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia.

OBJECTIVE: To isolate, evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia. METHODS: A total of 31 strains of actinomycetes were isolated and tested against Gram positive and Gram negative bacterial strains by primary screening. In the primary screening, 11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude extracts. The fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc and agar well diffusion methods. The isolates were characterized by using morphological, physiological and biochemical methods. RESULTS: The result obtained from agar well diffusion method was better than disc diffusion method. The crude extract showed higher inhibition zone against Gram positive bacteria than Gram negative bacteria. One-way analysis of variance confirmed most of the crude extracts were statistically significant at 95% confidence interval. The minimum inhibitory concentration and minimum bactericidal concentration of crude extracts were 1.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus, and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli respectively. The growth of aerial and substrate mycelium varied in different culture media used. Most of the isolates were able to hydrolysis starch and urea; able to survive at 5% concentration of sodium chloride; optimum temperature for their growth was 30 °C. CONCLUSIONS: The results of the present study revealed that freshwater actinomycetes of Lake Tana appear to have immense potential as a source of antibacterial compounds.

Protective effect of Lannea coromandelica Houtt. Merrill. against three common pathogens.

BACKGROUND: Ayurvedic text reports suggested Lannea coromandelica is used in various microbial origin disorders like dysentery, sore eyes and leprosy, genital wounds. OBJECTIVE: The present study was designed to investigate the antimicrobial effect of L. coromandelica Houtt. Merrill. (Anacardiaceae) on microbes which cause female reproductive tract infection. MATERIALS AND METHODS: Ethanolic and aqueous bark extract (Ext.) of L. coromandelica were screened against strains of Streptococcus pyogens, Staphylococcus aureus, and Candida albicans. Antimicrobial assay had been done with agar well diffusion method. RESULTS: Ethanolic extracts [100% (16 mg), 75% (12 mg) and 50% (8 mg)] of L. coromandelica exhibited zone of inhibition (ZI) 19.21 mm, 18.45 mm, 16.41 mm and 18.12 mm, 17.35 mm, 16.35 mm against S. aureus and S. pyogens, respectively. However, only 100% and 75% ethanolic extract showed (ZI-19.18 mm, 16.29 mm) activity against C. albicans. Nevertheless, aqueous extract (100%) showed higher antifungal activity (ZI-16.97 mm). Ciprofloxacin and amphotericin B were used as a standard drugs in the present study. CONCLUSION: The results demonstrated that L. coromandelica Houtt. Merrill. have antibacterial activity against S. pyogens, S. aureus and antifungal property against C. albicans. Our findings corroborate the ethnobotanical use of L. coromandelica in traditional medicine system (Ayurveda) of India.

Isolation and characterization of potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia

To isolate, evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia. Methods: A total of 31 strains of actinomycetes were isolated and tested against Gram positive and Gram negative bacterial strains by primary screening. In the primary screening, 11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude extracts. The fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc and agar well diffusion methods. The isolates were characterized by using morphological, physiological and biochemical methods. Results: The result obtained from agar well diffusion method was better than disc diffusion method. The crude extract showed higher inhibition zone against Gram positive bacteria than Gram negative bacteria. One-way analysis of variance confirmed most of the crude extracts were statistically significant at 95% confidence interval. The minimum inhibitory concentration and minimum bactericidal concentration of crude extracts were 1.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus, and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli respectively. The growth of aerial and substrate mycelium varied in different culture media used. Most of the isolates were able to hydrolysis starch and urea; able to survive at 5% concentration of sodium chloride; optimum temperature for their growth was 30 °C. Conclusions: The results of the present study revealed that freshwater actinomycetes of Lake Tana appear to have immense potential as a source of antibacterial compounds.

A study on anti dermatophytic potential of selected ethno medicinalplants against Trichophyton rubrum, a common etiologic agent in and around Visakhapatnam region (India)

Objective: The purpose of this study was to evaluate the clinical patterns and etiology of dermatophytosis and the anti dermatophytic potentiality of some selected medicinal plants used by tribal people in and around Visakhapatnam region, India. Methods: 62 patients with dermatophytosis who attended the dermatology clinic of King George hospital, Visakhapatnam were studied. Isolation and identification was done by direct microscopic observation, cultural characteristics and by using biochemical tests in the microbiology laboratory. Some ethno medicinal plant parts like Albizia lebbeck bark, Annona reticulata leaf and bark, Cassia fistula leaf, Wrightia tinktoria bark and Couroupita guianensis leaf were tested for anti dermatophytic activity by agar well diffusion method and minimum inhibitory concentration (MIC) studies were carried out by broth dilution assay. Results: 51 patients out of 62 were positive (82.2%) by direct smear and culture. Tinea corporis was the most common dermatophytosis which was predominantly caused by Trichophyton rubrum in and around Visakhapatnam. Two dermatophyte species were isolated and identified. Trichophyton rubrum was the most frequent isolate (58.8%) followed by Trichophyton mentagrophytes (19.6%). Albizia lebbek bark, Annona reticulata bark and leaf extracts showed inhibitory against T. rubrum while Cassia fistula leaf extract did not show significant inhibitory activity. Wrightia tinktoria bark and Couroupita guianensis leaf extracts did not show inhibitory activity. Conclusions: The results showed that tinea corporis was the most common dermatophytosis in and around Visakhapatnam region. Trichophyton rubrum was the most common etiologic agent. Albizia lebbek bark, Annona reticulata leaf and bark extracts showed potential inhibitory activity against Trichophyton rubrum than other tested ethno medicinal plants.

Antimicrobial activity of leaf extracts of Justicia adhatoda L. in comparison with vasicine

Objective: To ascertain the antimicrobial activity of methanolic leaf extracts of Justicia adhatoda and vasicine against Staphylococcus aureus, Streptococcus pyogenes, Serratia marcescens, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Cryptococcus neoformans and Aspergillus flavus. Methods: The antimicrobial activity of the concentrated leaf extracts of J. adhatoda was evaluated by determination of the diameter of zone of inhibition against bacteria and fungi. 25μg ml-1 concentration was used to check the antimicrobial activity of plant extracts and vasicine. Minimum inhibitory concentrations and minimum microbicidal concentrations were determined against all the pathogens. Sensitivity of the pathogens was also checked with four standard antibiotics, ciprofloxacin and ofloxacin for bacteria and nystatin and amphotericin B for fungi. Results: The phytochemical studies revealed the presence of alkaloids in the extracts were active against both bacteria and fungi. Studies on the minimum inhibitory concentration of the extracts on the test organisms showed that the lowest minimum inhibitory concentration and minimum microbicidal concentrations were demonstrated against Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa and the highest minimum inhibitory concentration was exhibited against Staphylococcus aureus, Streptococcuspyogenes, Klebsiella pnuemoniae. Among fungi Aspergillus flavus showed lowest minimum inhibitory concentration whereas Candida albicans and Cryptococcus neoformans showed highest minimum inhibitory concentration. Conclusion: The present study revealed that J. adhatoda has broad spectrum of antimicrobial activity and a potential source of antimicrobial agents that could be useful for chemotherapy and control of infectious diseases.

Preliminary Phytochemical Screening and Antimicrobial Studies of Lantana indica Roxb.

The aim of the present study was to investigate the antimicrobial and preliminary phytochemical properties of Lantana indica Roxb. The aqueous and organic solvent (ethyl acetate and methanol) extracts from the leaves of Lantana indica (Verbenaceae) were tested against Staphylococcus aureus, Bacillus subtilis, Steptococcus pyrogens, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Aspergillus niger and Candida albicans by agar well diffusion method. The results showed promising antibacterial activity against the tested bacteria. Among these, methanol and aqueous extracts were found to possess a more potent inhibitory effect when compared to the ethyl acetate extract. Preliminary phytochemical analysis of extracts revealed the presence of antimicrobial compounds such as carbohydrates, proteins, tannins and flavonoidal glycosides. The result of this study validates the use of methanol and aqueous extract of this species in ethnomedicine, favouring the isolation of antibacterial agents from the leaf extract of Lantana indica.

Antimicrobial Activities of Some Plants from the Eastern Anatolia Region of Turkey.

Crude extracts obtained from the roots and aerial parts of Rumex crispus.L. and Acinos rotundifolius.Pers. and the whole plants of Ajuga chamaepitys. L. and of Lycopus europaeus. L. were evaluated for in vitro. antimicrobial activity against five Gram-positive bacteria including Staphylococcus aureus., Micrococcus luteus, Mycobacterium smegmatis, Bacillus subtilis, Bacillus subtilis. var. niger., and three Gram-negative bacteria including Aeromonas hydrophila, Klebsiella pneumoniae, Pseudomonas aeruginosa., and the yeast Candida albicans.. The inhibition zone diameter was determined for each extract using the agar well diffusion method at a concentration of 12.5 mg/ml. The acetone extracts of the roots of R. crispus. and A. rotundifolius. demonstrated significant inhibitory effects against most microorganisms under test.