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.

Antimicrobial studies of rhizome of Swertia petiolata.

Swertia petiolata is used as folkore medicine in the treatment of skin diseases and mental disorders, ulcers, liver disorder and as bitter tonic, febrifuge, anthelmintic, antimalarial and antidiarrheal. Extracts of Swertia petiolata were prepared by soxhlet method. Dilutions were made in DMSO and subjected to antimicrobial activity by using agar well diffusion method, plate count agar (PCA) plates were inoculated with 100μl of each pathogenic microorganism adjusted to standardized inoculum (1.5 × 108 CFU/ml) in triplicates and spread with sterile swabs. After incubation for 24 hrs at 37 °C, the plates were observed. The zone of inhibition was measured and expressed in millimeters. Whereas the standard antibiotics; cefutaxim and amoxicillin showed antimicrobial activity with zones of inhibition ranging from > 15 mm to 10-15 mm. The hydro methanol extract showed excellent activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis = 10-15mm), Gram-negative bacteria (Escherichia coli = 10-15 mm). However chloroform and petroleum ether extracts did not show significant antibacterial activity reflected by >4mm (gram +ve) and 5-10 mm (Gram-ve) and >4 mm (Petroleum ether extract). Phytochemical analysis of the extract showed the presence of steroids, tannins, phenolics, saponins, alkaloids, flavonoids and glycosides. From the study, it can be concluded that Swertia petiolata possesses significant antimicrobial activity which might be due to the presence of any/all these active constituents.

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). Ciprofl oxacin 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 fi ndings 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.

Evaluation of Malawian Vernonia glabra (Steetz)Vatke leaf and Securidaca longepedunculata (Fresen) root extracts for antimicrobial activities.

The aqueous, ethanol and acetone crude extracts and dichloromethane, hexane, ethyl acetate and nbutanol fractions of the Securidaca longepedunculata roots and Vernonia glabra leaves were studied for their antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans using agar well diffusion method. The phytochemical presents, as well as the minimum inhibitory concentration (MIC) and minimum bacteriacidal/fungicidal concentration (MBC/MFC) of the extracts were also determined using standard methods. Results obtained indicated that Vernonia glabra leaves acetone extracts had excellent antimicrobial activity against E. coli, P. aeruginosa and ethanol extracts against S. aureus. The n-butanol fractions had the best activity against E. coli and S. aureus, dichloromethane fraction against P. aeruginosa and ethyl acetate fraction against C. albicans. For S. longepedunculate root ethanol extracts showed best activity against E. coli, acetone extract against P. aeruginosa and aqueous extract against C. albicans. The n-butanol fractions had best activity against E. coli, P. aeruginosa and C. albicans. These results verified the claims by traditional healers in Malawi that the plants extracts treats bacteria related ailments such as diarrhoea and could be a potential source for development of phytomedicine.

In vitro assessment of antimicrobial activity of the selected essential oils.

The present study evaluates the antimicrobial activity of three essential oils of Eucalyptus globulus, Eugenia caryophyllata and Psoralea corylifolia. The agar well diffusion method was used to assess the antimicrobial activity against five selected microorganisms S. aureus and B. subtilis (Gram-positive bacteria); E. coli and P. aeruginosa (Gram-negative bacteria) and P. chrysogenum (Fungus). The results revealed that the E. globulus was found to be most significant in comparison to the other oils. All the three oils have revealed higher antimicrobial activity against S. aureus.

In vitro antibacterial activity of Terminalia chebula leaf gall extracts against some human pathogenic strains.

The leaf galls of Terminalia chebula is used widely as Karkatasringi in south Indian markets. Karkatashringi is an important crude drug employed in various indigenous systems of medicine against several diseases and the drug has diverse medicinal properties. The present study was carried out to understand the antimicrobial activity of various extracts. The antibacterial activity of T. chebula (leaf gall) was evaluated against ten bacterial strains including Gram-positive and Gram-negative bacteria using the agar-well diffusion method. Among the two extracts tested, the ethanol extract presented the best results against all the bacteria while aqueous extract showed moderate inhibition of the microbial growth. Each extract is unique against different microorganisms; Staphylococcus aureus was more susceptible to both extract among the tested organisms, whereas Serratia marcescens and Proteus mirabilis were less susceptible for ethanol and aqueous extract respectively. The inhibitory effect of the extracts was compared with standard antibiotic Ciprofloxacin.

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.