The in vitro antimicrobial activity of fruit and leaf crude extracts of Momordica charantia: A Tanzania medicinal plant

Objective

To evaluate the antimicrobial activity of Momordica charantia extracts on reference strains and microorganisms isolated from clinical specimens.

Method

Petroleum ether and methanolic crude extracts of fruits and leaves of the plant were evaluated for antimicrobial activity using the disk diffusion method on four reference microorganisms (Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Staphylococcus aureus; and four clinical strains of Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhi and Cryptococcus neoformans.

Result

Antimicrobial activity was observed against all the tested microorganisms with exception to P. mirabilis and C. neoformans. Methanolic crude extracts exhibited relatively broader antimicrobial spectrum of activity than petroleum ether extracts with the as lower concentration as 0.075mg/µl. Methanolic fruit crude extract displayed the broadest antimicrobial spectrum by inhibiting majority (75%) of the tested microorganisms. Neither was there synergistic nor addition effect upon mixing leaf and fruit extracts of equal concentrations derived from the same solvent.

Conclusion

Extracts of M.charantia demonstrated antimicrobial activity on tested microorganisms except on Proteus mirabilis and Cryptococcus neoformans. Fruit extracts showed higher antimicrobial activity than leaf extract. Further studies are recommended that will involve various parts of the plant, select different fractions of extracts and purify the active antimicrobial components.     

Antibacterial and Anti-Biofilm Activity of Flavonoids and Triterpenes Isolated from the Extracts of Ficus Sansibarica Warb. Subsp. Sansibarica (Moraceae) Extracts

Background

Ficus species are used in African traditional medicine in the treatment of a wide variety of ailments and diseases such as convulsive disorder, wound healing, gonorrhea, tuberculosis, diabetes, diarrhoeal infections, dysentery, malaria and HIV. The aim of this study was to isolate the phytochemical constituents in the plant and test them for their antibacterial activity.

Materials and methods

The fruits, leaves and stem bark were extracted with organic solvents and the compounds in the extracts separated and purified by column chromatography before being identified by NMR spectroscopy and by comparison of the NMR data against values reported in the literature. The antibacterial activity of the pure compounds and extracts were tested using the disk diffusion method.

Results

Three triterpenes and three flavonoids: lupeol acetate (1); cycloart-23-ene-3,25-diol (2); β-sitosterol (3); 5,7,4′-trihydroxyflavan-3-ol (4); epicatechin (5); and isovitexin (6) were isolated in this study. Antimicrobial activity was observed at 8 mg mL⁻¹ for Staphylococcus aureus ATCC 29213 with four of the six isolated compounds, with no activity being observed at 1 – 4 mg mL⁻¹ against Escherichia coli ATCC 25922, E. coli ATCC 35218 and S. aureus ATCC 43300. Epicatechin (5) was found to decrease adhesion of E. coli ATCC 25922 and S. aureus ATCC 29213. Decreased adhesion of S. aureus ATCC 29213 was also observed with 5,7,4′-trihydroxyflavan-3-ol (4) and isovitexin (6).

Conclusions

The results of this study provide baseline information on F. sansibarica''s potential validity in the treatment of infections associated with Gram-positive microorganisms.     

Bacillus Spp. isolated from the conjunctiva and their potential antimicrobial activity against other eye pathogens

Background

In this study, we attempted to screen and investigate antibacterial activity of Bacillus species, which were isolated from conjunctiva, against other eyes pathogens.

Methods

To examine predominant isolates of Bacillus subtilis, B. pumilus, B. cereus and B. mojevensis, isolated from conjunctiva for their antimicrobial activity against indicator microorganisms as Micrococcus luteus, Staphyloccocus aureus, S. epidermidis, S.hominis, S. lugdunensis, S.warneri, S. haemolyticus, B. cereus, Listeria monocytogenes, and Proteus mirabilis. Growth inhibitions of indicator microorganisms were tested using agar diffusion tests by cells and supernatants of five B. mojevensis, one B. subtilis, four B. cereus and five B. pumilus strains which were isolated from conjunctiva.

Results

The Bacillus isolates showed variable ability of inhibition against the tested microorganisms. Two strains of B. pumillus, 1 strain of B. subtilis, 5 strains of B. mojevensis, 1 strain of B. cereus were efficacious against the tested microorganisms. Most resistant microorganism to these bacteria was Proteus mirabilis. Two of Gram positive bacteria, S. lugdenensis (K15-9) and S. aureus (SDA48), were also found as resistant.

Conclusions

In this study, Bacillus spp isolated from conjunctiva showed antimicrobial activity against Gram-positive bacteria. Human eye-derived microorganisms and their antimicrobial effects might be a useful source of natural products for the future.     

The Antimicrobial Activity of Liquidambar Orientalis Mill. Against Food Pathogens and Antioxidant Capacity of Leaf Extracts

Background

Medicinal plants are an important source of substances which are claimed to induce antimicrobial, antimutagenic and antioxidant effects. Many plants have been used due to their antimicrobial treatments. Antimicrobial and antioxidant activities of L. orientalis have not been reported to the present day. The aim of this work was to investigate of the antimicrobial and antioxidant potentials of different extracts from L. orientalis.

Materials and Methods

The extracts were screened for antimicrobial activity against different food pathogens. These bacteria include 4 Gram positive and 3 Gram negative bacteria and one fungi. The leaf extracts of plant were tested by disc diffusion assay. The MIC was evaluated on plant extracts as antimicrobial activity. In addition to, the plant extracts were tested against the stable DPPH (2,2-diphenyl-1-picryl-hydrazylhydrate) free-radical.

Results

The acetone, ethanol and methanol extracts of L. orientalis showed maximum inhibition zone of 12 mm against Yersinia enterocolitica, Listeria monocytogenes and Staphylococcus aureus. In addition to, the methanol extract displayed a strong antioxidant activity (trolox equivalent = 2.23 mM).

Conclusion

L. orientalis extracts have antimicrobial, and antioxidant potential. Our results support the use of this plant in traditional medicine and suggest that some of the plant extracts possess compounds with good antibacterial properties that can be used as antibacterial agents in the search for new drugs.     

Antimicrobial, Wound Healing and Antioxidant Activities of Anthocephalus Cadamba

Anthocephalus cadamba (Roxb.) Miq. Syn A. chinensis (Lamk) A. Rich (Rubiaceae) is ethnomedicinally widely used in the form of paste by tribe in western Ghats for treating skin diseases. In this context, antimicrobial potential of A. cadamba against a wide range of microorganisms was studied. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing. The alchoholic and aqueous extract of this plant showed significant antibacterial and antifungal activity against almost all the organisms: Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and four fungi Candida albicans, Trichophyton rubrum—dermatophyte fungi, Aspergillus niger, Aspergillus flavus and Aspergillus nidulans—systemic fungi, with especially good activity against the dermatophyte (Trichophyton rubrum) and some infectious bacteria (Escherichia coli, Proteus mirabilis and Staphylococcus aureus) with an MIC of 2.5 µg/disc. The results show that A. cadamba extract has potent wound healing capacity as shown from the wound contraction and increased tensile strength. The results also indicated that A. cadamba extract possesses potent antioxidant activity by inhibiting lipid peroxidation and increase in the superoxide dismutase (SOD) and catalase activity.     

Phytochemical and In Vitro Antimicrobial Assay of the Leaf Extract of Newbouldia Laevis

The methanolic leaf extract of Newbouldia laevis was subjected to preliminary phytochemical screening and in-vitro antimicrobial tests. The extract revealed the presence of flavonoids, tannins, terpenes, steroidal and cardiac glycosides. The antimicrobial activity of the plant extract was assayed by the agar plate disc diffusion and nutrient broth dilution techniques. Test microorganisms were Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Klebsiella spp. and Candida albicans; all the organisms were laboratory isolates. The extract inhibited the growth of all the test organisms especially against Klebsiella spp. and S. aureus which had mean inhibition zone of 42.3±1.5 and 32.3±1.5 mm respectively. The results showed minimum inhibitory concentration (MIC) of 1.563 mg/ml against Escherichia coli and Klebsiella spp. and 3.125 mg/ml against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. The minimal bactericidal concentration (MBC) against Escherichia coli and Staphylococcus aureus was 0.39 mg/ml. This study has justified the traditional use of this plant for the treatment of stomach discomfort, diarrhea, dysentery and as a remedy for wound healing whose causative agents are some of the organisms used in this study.     

Anti-Ulcer and Wound Healing Activities of Sida Corymbosa in Rats

Background

There are strong beliefs in the efficacy of traditional medical systems worldwide. Many herbs have been acclaimed to possess antiulcer effects and could be unexplored sources of new lead compounds. Sida corymbosa R. E. Fries (Malvaceae) is used in Northern Nigeria to treat ulcers and wounds. This work aimed to investigate the usefulness of Sida corymbosa in treatments of stomach ulcers and wounds in traditional medicine.

Materials and Methods

Effect of the aqueous extract was determined on gastric ulceration, rate of wound healing and inflammation using ethanol-induced and diclofenac-induced ulceration, wound excision model and albumin-induced inflammation respectively in rats.

Results

The study demonstrated the anti-ulcer activity of Sida corymbosa as the extract (250, 500 and 1000 mg/kg) showed a dose-dependent, significant (P<0.05) reduction of ulcer indices against gastric ulcers induced by both ethanol and diclofenac. Topical application of a formulation prepared with the extract of Sida corymbosa on surgically created incisions produced an increase in the rate of healing of the wounds. The extract of Sida corymbosa exhibited a significant (P < 0.05), dose-related decrease in inflammation induced by fresh egg albumin. This study showed that Sida corymbosa has constituents with the ability to reduce the severity of haemorrhagic gastric lesions, promote wound healing and reduce inflammation. These actions may be attributed to any one of the active constituents or as a result of synergistic effects of these phytoconstituents.

Conclusion

This study validates the use of the plant in traditional medicine for the treatment of stomach ulcers and wounds.     

In-vitro antimicrobial activity of selected honeys on clinical isolates of Helicobacter pylori

Background

Helicobacter pylori is a gram-negative bacterium incriminated in gastroduodenal ulcers, and mucosa-associated lymphoid tissue lymphoma imposing a major burden on health care systems worldwide. Honeys have been shown to have in vitro activity against microaorganisms and suitable for use in ulcers, infected wounds and burns.

Objective

The study was aimed at evaluating the antimicrobial potential of honeys (Manuka−, Capillano®, Eco- and Mountain) at different concentrations (10%v/v, 20%v/v, 50%v/v and 75%v/v) against clinical isolates of H. pylori.

Methods

H. pylori was isolated from gastric biopsies of patients with gastroduodenal pathologies following standard microbiological procedures. Antimicrobial susceptibility of the isolates to different honey varieties was determined by the disk diffusion assay. Also, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the most potent honey was determined by the agar dilution method. Data were analysed using the Fisher exact test and statistical significance considered at p<0.05.

Results

All the four honey varieties exhibited antibacterial activity. The strongest inhibitory activity (82.22%) was demonstrated by Mountain honey at 75%v/v, followed by Capillano® and Manuka− honeys (75.56%), and Eco-honey (73.36%) at the same concentration. However, no statistically significant difference (p>0.05) was noted between the honeys at different concentrations. The MIC and MBC concentrations of Mountain honey were in the range 0.117 – 0.938ì/mL and 0.366 – 2.965ìg/mL respectively. The antimicrobial potential of these honeys at different concentrations were highly comparable to clarithromycin, the positive control.

Conclusion

These honeys may contain compounds with therapeutic potential against our local isolates of H. pylori.     

Evaluation of antibacterial,antifungal and modulatory activity of methanol and ethanol extracts of Padina sanctae-crucis

Background

Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of microbial infections. Padina sanctae-crucis is a seaweed often used to check the contamination of ecosystems by materials such as heavy metals, but studies of the antimicrobial activity of the same seaweed were not found.

Methods

The tests for the minimum inhibitory concentration and modulation of microbial resistance, with the use of ethanolic and methanolic extracts of Padina Sanctae-cruces combined with drugs of the class of aminoglycosides and antifungal were used to evaluate the activity against the cited microorganisms.

Results

Was observed a modulation of antibiotic activity between the natural products and the E. coli and S. aureus strains, indicating a synergism and antagonism respectively.

Conclusions

The results showed a moderate modulatory effect against some microorganisms studied.     

Evaluation of Antioxidant and Antimicrobial Potential of Two Endangered Plant Species Atropa Belladonna and Matricaria Chamomilla

Background

Plants are the natural source of antioxidants as well as antimicrobial compounds that has great potentials in pharmaceutical industry. In the present study, two medicinal plants Atropa belladonna and Matricaria chamomilla were collected from Northern areas of Pakistan.

Materials and Methods

The extracts of the collected plants were obtained by microwave assisted extraction (MAE) with changing parameters, power level and time; methanol and ethanol were solvents used during extraction. The extracts of plants were tested against different bacterial strains.

Results

It was observed that ethanolic extracts of Atropa belladonna has more significant antimicrobial activity against S.aureus than E.coli. In parallel, methanolic extract of Matricaria chamomilla showed greater significant antibacterial activity against S.aureus when compared with E.coli. In comparison, ethanolic extracts of Matricaria chamomilla has shown more significant results against S. aureus than E.coli (p≤0.05). Both plants had no antibacterial activity against S.typhi. The free radical scavenging activity observed by DPPH assay, indicate that both plants have antioxidant activity at all levels of concentrations in solvent tested during the present work. However, methanolic extracts had greater antioxidant activity when compared with ethanolic extracts.

Conclusion

Present study is thus helpful in highlighting present potentials for antioxidant and antimicrobial properties in the selected plants.     

Antioxidant and Antibacterial Activities of Flavonoid Glycosides from Ficus Exasperata Vahl-Holl (Moraceae) Leaves

Background

Ficus exasperata Vahl-Holl (Moraceae) leaves are used for infectious and inflammatory conditions in many West African Countries. However, there is need for more phytochemical studies to justify the ethnomedicinal uses of the plant.

Material and Methods

The crude 50% aqueous ethanolic extract of the leaves was partitioned successively between water and; n-hexane, ethyl acetate and n-butanol. The fractions were subjected to antimicrobial activity using agar diffusion test. n-Butanol fraction, which showed both antimicrobial and radical scavenging activities was subjected to repeated chromatographic fractionation on both silica and Sephadex LH-20 columns. Each stage of the purification was monitored by thin layer chromatographic diphenylpicryl hydrazyl autographic assay. Three compounds were isolated. The structures of the compounds were elucidated using spectroscopic methods, shift reagent studies, acid hydrolysis, and by comparison with literature data.

Results

The compounds were identified as apigenin C-8 glucoside (1), isoquercitrin-6-O-4-hydroxybenzoate (2) and quercetin-3-O-β-rhamnoside (3). The solvent fractions and isolated compounds were found to inhibit the growth of Gram +ve organisms only.

Conclusion

These flavonoid glycosides are being reported in this plant species for the first time. Their weak in vitro antimicrobial activity suggest the flavonoids may be acting as pro-drug. The radical scavenging activity of the compounds may justify some of the ethnomedicinal uses of the plant as free radicals are implicated in the aetiology of many inflammatory diseases.     

Antimicrobial Activity of Methanolic Extracts of Sambucus Ebulus and Urtica Dioica Against Clinical Isolates of Methicillin Resistant Staphylococcus Aureus

Background

Increase in the emergence of drug -resistant pathogens led to the development of natural antimicrobials. In this study the antimicrobial effect of methanolic extracts of Sambucus ebulus and Urtica dioica on 16 skin and wound infections isolates of methicillin resistant S. aureus have been studied.

Material and Methods

Solvent extraction procedure was done using soxhlet apparatus for extracting antimicrobial agents from freeze dried plants. Antibacterial activity was measured using agar well diffusion method.

Results

The MIC of Sambucus ebulus and Urtica dioica extracts against the standard strain of S. aureus ATCC 6538 were determined using the micro dilution method at 15 mg and 20 mg respectively. All the test bacteria were found sensitive to the Sambucus ebulus extract and only one isolate was resistant to Urtica dioica extract.

Conclusion

Extracts of Sambucus ebulus and Urtica dioica possess antibacterial potency against MRSA isolates and may be used as a natural antiseptics and antimicrobial agents in medicine.     

A Study on Antimicrobial,Antioxidant and Antimutagenic Activities of Elaeagnus Angustifolia L. Leaves

Backround

The aim of this work was to investigate the antimicrobial, antioxidant, and antimutagenic potentials of methanol extracts from E. angustifolia.

Materials and Methods

Methanol extracts were screened for antimicrobial activity against different species of 4 Gram positive and 3 Gram negative bacteria and one fungus. These bacteria included food pathogens. The leaf extract was tested using disc diffusion assay.

Results

The methanol extract of E. angustifolia showed maximum inhibition zone of 16 mm against Yersinia enterocolitica. Whereas, the inhibition zone was not determined by methanol extract against Escherichia coli ATCC 1122 and Candida albicans RSKK 02029. The MIC was evaluated on plant extracts as antimicrobial activity. All of bacterial strains showed the lowest sensitivity to methanol extract of E. angustifolia (3.5 mg/mL), except Yersinia enterocolitica NCTC 11174. In addition, the plant extracts were tested against the stable DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free-radical. Finally, the methanol extract displayed a strong antioxidant activity (Trolox equivalent = 1.49 mM). Also, E. angustifolia methanol extracts were screened for their antimutagenic activity against sodium azide by Ames test in absence of rat microsomal liver enzyme (-S9). The results showed that E. angustifolia methanol extracts can inhibit mutagenic agents of sodium azide. The plant leaf extracts with the inhibition of 36% sodium azide showed moderate potential in decreasing mutagenic agents in Salmonella typhimurium TA100.

Conclusion

E. angustifolia methanol extracts have antimicrobial, antioxidant and antimutagenic potential.     

Antimicrobial Activity of Various Extracts of Ocimum Basilicum L. and Observation of the Inhibition Effect on Bacterial Cells by Use of Scanning Electron Microscopy

The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Ocimum basilicum L. were studied. These extracts were tested in vitro against 10 bacteria and 4 yeasts strains by the disc diffusion method. The results indicated that the methanol extracts of O. basilucum exhibited the antimicrobial activity against tested microorganisms. While the chloroform and acetone extracts had no effect, the methanol extracts showed inhibition zones against strains of Pseudomonas aeruginosa, Shigella sp., Listeria monocytogenes, Staphylococcus aureus and two different strains of Escherichia coli. The cells of microorganisms, which were treated and untreated with plant extracts, were observed by using the scanning electron microscope. It was observed that the treated cells were damaged.     

Extraction and Isolation of Alkaloids of Sophora Alopecuroides and Their Anti-Tumor Effects in H22 Tumor-Bearing Mice

Background

Alkaloids of Sophora alopecuroides have good biological activity, and are widely used in clinical settings, which not only have pharmacological activities of anti-cancer, cancer suppression, as well as the inhibition, and killing of various microorganisms; but also possess extensive pharmacological effects on immune system, nervous system and cardiovascular system. The objective of this paper was to extract and isolate total alkaloids of Sophora alopecuroides (TASA), and to study their anti-tumor effects in H22 tumor-bearing mice.

Materials and Methods

TASA were extracted and isolated using thin-layer chromatography, and column chromatography; and the isolated compounds were analyzed using nuclear magnetic resonance. The inhibitory effects of TASA on tumor in H22-bearing mice were determined by MTT assay.

Results

Three compounds were isolated from Sophora alopecuroides L., which were matrine, oxymatrine and sophoridine, respectively. Meanwhile, mouse H22 sarcoma model was established and different doses of TASA apparently inhibited solid H22-tumor in mice; it inhibited the thymus, and spleen to some extent; the degree of inhibition was more obvious for the spleen.

Conclusion

TASA has an anti-tumor effect in H22 tumor-bearing mice.     

Phenolic Composition,Antioxidant Capacity of Salvia Verticcilata and Effect on Multidrug Resistant Bacteria by Flow-Cytometry

Background

Antioxidants are of great importance for preventing oxidative stress that may cause several degenerative diseases. Studies have indicated phytochemicals have high free-radical scavenging activity, which helps to reduce the risk of chronic diseases. The aim of the present study is the determination of antioxidant properties, polyphenolic content and multidrug resistant bacteria of Salvia verticcilata L.

Materials and Methods

Methanol was used as the extraction solvent. The total phenolic content was calculated using Folin-Ciocalteau method and phenolic composition was determined by HPLC. The radical scavenging activity of plant was evaluated in vitro based on the reduction of the stable DPPH free radical. The reducing capacity was identified by using the FRAP method. The ability of Salvia verticcilata L. to increase the permeability of multidrug resistant bacterial cells was conducted by flow cytometric assay on Listeria innocua and E-coli.

Results

The amount of total phenolics was found to be 347.5 mg GA/g extract. The IC₅₀ value and FRAP assay are 0.61, and 0.944 respectively, Free radical scavenging effect and FRAP values are less than synthetic antioxidant compounds (BHA and BHT). Eight phenolic compounds were found in Salvia verticcilata L. Intense concentration of S. verticcilata L. has destroyed 97 % of living cells for Listeria innocua and 94.86% for E-coli

Conclusion

This studyshows that methanolic extracts of Salvia verticcilata L. is a potential source of natural antioxidants and antimicrobial agent and can form the basis for pharmacological studies.     

Antibacterial agents from the leaves of Crinum purpurascens herb (Amaryllidaceae)

Background

Typhoid fevers and urogenital infections continue to be serious health problems in developing countries. In our search for therapeutic agents from natural sources with potential for the treatment of typhoid fevers and urogenital infections, extract and compounds were obtained from Crinum purpurascens and tested.

Methods

Two alkaloids (4,5-ethano-9,10-methylenedioxy-7-phenanthridone or hippadine (1) and 4,5-ethano-9-hydroxy-10-methoxy-7-phenanthridone or pratorimine (2)) and one steroid (â-D-glucopyranoside of sitosterol (3)) were isolated from the CH₂Cl₂/MeOH (1:1) leaf extract of Crinum purpurascens and screened for antibacterial activity using both agar diffusion and broth dilution techniques.

Results

For the CH₂Cl₂/MeOH extract, the MIC values obtained were 3 mg/ml (against P. aeruginosa), 4 mg/ml (against E. coli, K. pneumoniae and S. aureus) and 6 mg/ml (against S. typhi and S. paratyphi B), whereas the MBC values varied between 7 and 12 mg/ml. For compound 1, the MIC values varied between 200 and 250 µg/ml, whereas the MBC value was 300 µg/ml against all the bacteria strains used. Compound 2 did not show any antimicrobial activity against these bacteria strains. For compound 3, the MIC values varied between 250 and 300 µg/ml, whereas the MBC values were 300 µg/ml (against S. typhi and S. paratyphi B) and > 300 µg/ml (against the other bacteria strains).

Conclusion

These data suggest that C. purpurascens leaf extract contains antibacterial agents which could be used in the treatment of typhoid fevers and urogenital infections.     

Preliminary Examination of Herbal Extracts on the Inhibition of Helicobacter Pylori

Background

This work aims at describing the traditional uses, to determine the antimicrobial potential of two different extracts hexane, acetone of the leaves of Citrus unshiu, Citrus sinensis, Citrus limon, Laurus nobilis, Citrus paradisi on clinical strain of H. pylori in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs. H. pylori strain was a culture collection of Hacettepe University, Turkey.

Methods

The activity was quantitatively assessed on the basis of the inhibition zone, and their activity index was also calculated along with the MIC method.

Results

All the plants demonstrated antimicrobial activity against H. pylori with zone of inhibition diameters ranging from 0 – 30 mm and minimum inhibitory concentration (MIC) values ranging from 1:512–1:4096 dilutions.

Conclusion

The results may serve as scientific validation of the ethnomedicinal uses of the Citrus unshiu, Citrus sinensis, Citrus limon, Laurus nobilis, and Citrus paradisi in the treatment of H. pylori-related infections. However, further investigations would be necessary to determine their toxicological properties, in-vivo potencies and mechanism of action against H. pylori.     

Antimicrobial resistance and prevalence of resistance genes in intestinal Bacteroidales strains

OBJECTIVE:

This study examined the antimicrobial resistance profile and the prevalence of resistance genes in Bacteroides spp. and Parabacteroides distasonis strains isolated from children''s intestinal microbiota.

METHODS:

The susceptibility of these bacteria to 10 antimicrobials was determined using an agar dilution method. β-lactamase activity was assessed by hydrolysis of the chromogenic cephalosporin of 114 Bacteriodales strains isolated from the fecal samples of 39 children, and the presence of resistance genes was tested using a PCR assay.

RESULTS:

All strains were susceptible to imipenem and metronidazole. The following resistance rates were observed: amoxicillin (93%), amoxicillin/clavulanic acid (47.3%), ampicillin (96.4%), cephalexin (99%), cefoxitin (23%), penicillin (99%), clindamycin (34.2%) and tetracycline (53.5%). β-lactamase production was verified in 92% of the evaluated strains. The presence of the cfiA, cepA, ermF, tetQ and nim genes was observed in 62.3%, 76.3%, 27%, 79.8% and 7.8% of the strains, respectively.

CONCLUSIONS:

Our results indicate an increase in the resistance to several antibiotics in intestinal Bacteroides spp. and Parabacteroides distasonis and demonstrate that these microorganisms harbor antimicrobial resistance genes that may be transferred to other susceptible intestinal strains.     

Anti-Bacterial and Anti-Oxidant Activities of Leaf Extracts of Combretum Vendae (Combretecacea) and the Isolation of an Anti-Bacterial Compound

Background

Combretum vendae A.E. van Wyk (Combretaceae) is used for the treatment of bacterial related infections and oxidative related diseases by indigenous people of South Africa. Dried leaves extracts of C. vendae were investigated for bioactivity against a variety of bacterial strains and their antioxidant potential evaluated.

Materials and methods

Constituents of leaf material were serially extracted using solvents of varying polarities, TLC chromatograms of the fractions were sprayed with 2,2 diphenyl-1-picrylhydrazyl (DPPH) to determine the presence of antioxidant compounds. Bio-autography was used to determine the number of antibacterial compounds active against Staphylococcus aureus, Enterococcus faecalis, Eschericha coli and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) values were determined using serial microplate dilution method. The chloroform fraction was subjected to bio-assay guided column chromatography to isolate the active compound.

Results

The mass extracted by different solvents was below 10% dry weight. MIC values for different extracts against different pathogens ranges from 0.08 to 0.64 mg/ml. The compound isolated was identified as acacetin having an R_f value of 0.28 following elution in the Ethanol: Methanol: Water [E: M: W (10: 1.35: 1 v/v). Acacetin had MIC values ranging from 0.16 to 0.35 mg/ml.

Conclusion

We report for the first time the isolation of acacetin as the main antibacterial compound from the leaves of Combretum vendae.