Antimicrobial Activity of Some Medicinal Plants Used by Herbalists in Eastern Province, Kenya

The aqueous extracts from medicinal plants commonly used by herbalists in Mbeere, and Embu districts of Eastern province, Kenya, were tested for their inhibitory activity against three selected strains of bacteria. All the selected plant extracts (infusions: 1.0g sample in 100 ml water) investigated showed activity against Escherichia coli with inhibition zone diameters ranging from 5.8 – 18.0 mm. Terminalia brownii gave the largest inhibition zones against E. coli and Staphylococcus aureus. Vernonia lasiopus and Tithonia diversifolia were inactive to S. aureus and Bacillus subtilis, respectively. Eighteen and sixteen plants showed sensitivity of greater than 10 mm against S. aureus and B. subtilis, respectively. All control discs gave zones of inhibition of 12 – 24 mm, which were larger than those of the extracts. The present study validated the use of the selected medicinal plants by the herbalists in the treatment of bacterial ailments caused by the strains of bacteria investigated. Medicinal plants used for non-bacterial diseases also exhibited sensitivity towards bacterial strains tested. This implied they could be used as multi-purpose medicinal plants.     

Antimicrobial Effects of Three Tropical Plant Extracts on Staphylococcus Aureus, Escherichia Coli and Candida Albicans

Antimicrobial activities of the leaf extracts of Cymbopogon citatrus (lemongrass) and Vernonia amygdalina (bitter leaf) and the seed extracts of Garcinia kola (bitter kola) were carried out. G. kola had effect only on Staphyococcus aureus and Escherichia coli with no inhibition on Candida albicans. Ethanol, cold water and hot water extracts of Vernonia amygdalina and Cymbopogon citratus showed inhibition on the three organism but G. kola ethanol, cold water and hot water extracts only inhibited S. aureus and E. coli with no inhibition on Candida albicans. The organism''s susceptibility varied with more inhibition to S. aureus and least to Candida albicans.     

Phytochemical and Antimicrobial Effects of Chrozophora Senegalensis

The in vitro antimicrobial activities of the whole plant extract (ethanolic-CEE) of Chrozophora senegalensis and its fractions (ethyl acetate-EAA, n-butanol-NBE, aqueous-AQE) were assayed using the agar plate diffusion and nutrient broth dilution methods. Test microorganisms were Bacillus subtilis (NCTC 8326 B76), Escherichia coli (ATCC 11775), Pseudomonas aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 021001). Aspergillus flavus, Aspergillus niger, Candida albicans and Salmonella typhi - laboratory isolates. CEE, EAA and NBE inhibited all the test bacterial organisms and a fungus-Aspergillus flavus. AQE inhibited only Salmonella typhi and Bacillus subtilis. None of the extracts had activity on other 3 fungal organisms tested. CEE and EAA showed minimum inhibition concentration (MIC) of 0.390 and 3.125 mg/ml against S. typhi and E. coli, while NBE and AQE had MIC of 3.125 and 1.563 mg/ml against S. typhi respectively. NBE had an MIC of 12.500 mg/ml against E. coli. The minimum bactericidal concentration (MBC) of CEE and EAA was found to be <0.098 against S. typhi. The MBC of AQE was 12.5 mg/ml against E. coli and S. aureus, and 6.25 mg/ml towards P. aeruginosa. CEE and EAA exhibited similar antibacterial activities, followed by AQE. The extracts revealed the presence of carbohydrates, tannins, saponins, sterols determined by utilizing standard methods of analysis.This study has justified the traditional use of the plant for treating diarrhea, boils and syphilis.     

Antimicrobial Activity of Extracts and Topical Products of the Stem Bark of Spathodea Campanulata for Wound Healing

The antibacterial activity of the aqueous, ethanol, methanol and petroleum ether Soxhlet extracts of sundried stem bark of Spathodea campanulata P. Beauv. (Bignoniaceae) was investigated by testing the extracts against B. subtilis, E. coli, P. aeruginosa and S. aureus. The minimum inhibitory concentration (MIC) of the methanol extract was determined against the four bacteria strains and C. albicans using the broth dilution method. Four topical products were prepared by incorporating the methanol extract of S. campanulata (20 % w/w) into aqueous cream, soft paraffin, emulsifying ointment and simple ointment bases and evaluated for their in vitro antimicrobial efficacy. The effect of storage time on the activity of the methanol extract of S. campanulata and S. campanulata extract incorporated in aqueous cream base was also investigated. The methanol and ethanol extracts showed good activity while the aqueous and petroleum ether extracts exhibited little activity. The methanol extract showed the best antibacterial activity. The MIC of the methanol extract of S. campanulata was: C. albicans (45 – 50 mg/ml), B. subtilis and E. coli (50 – 55 mg/ml), P. aeruginosa (60 – 65 mg/ml), S. aureus (145 – 150 mg/ml). Antimicrobial activity of S. campanulata in the topical bases was in the order: aqueous cream > emulsifying ointment > simple ointment > white soft paraffin. Antimicrobial activity of S. campanulata in aqueous cream decreased (p < 0.05) upon storage at room temperature for 6-months. The antifungal activity of the methanol extract of S. campanulata was reduced (p < 0.05) upon storage while antibacterial activity was largely unaffected.     

Effects of natural honey on polymicrobial culture of various human pathogens

Introduction

Honey has a wide range of antimicrobial activity. All previous studies have considered honey''s effect on a single microbe. The present study investigated activity of honey towards a high dose of single or polymicrobial culture.

Material and methods

10 µl specimens of Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), Escherichia coli (E. coli) and Candida albicans (C. albicans) were cultured in 10 ml of 10-100% (wt/v) honey diluted in broth. Six types of polymicrobial microbial cultures were prepared by culturing the isolates with each other onto broth (control) and broth containing various concentrations of honey (10-100% wt/v). Microbial growth was assessed on solid plate media after 24 h incubation.

Results

Honey (30-70%) prevents growth of 10 µl specimens of all the isolates. Greater reduction in growth of E. coli was observed when cultured with S. aureus. Culturing of S. aureus with S. pyogenes, C. albicans, or E. coli increased its sensitivity to honey. S. aureus and S. pyogenes increased sensitivity of C. albicans to honey while E. coli and C. albicans decreased sensitivity of S. pyogenes.

Conclusions

It might be concluded that honey prevents and inhibits growth of single and polymicrobial pathogenic cultures. Polymicrobial culture affects growth of the isolates and increases their sensitivity to honey.     

In Vitro Antimicrobial Activity of Crude Extracts from Plants Bryophyllum Pinnatum and Kalanchoe Crenata

Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe crenata were screened for their antimicrobial activities. Solvents used included water, methanol, and local solvents such as palmwine, local gin (Seaman''s Schnapps 40% alcoholic drink,) and “omi ekan-ogi” (Sour water from 3 days fermented milled maize). Leaves were dried and powdered before being soaked in solvents for 3 days. Another traditional method of extraction by squeezing raw juice from the leaves was also employed. All extracts were lyophilized. These extracts were tested against some Gram-negative organisms (Escherichia coli ATCC 25922, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella flexneri, Salmonella paratyphi, Citrobacter spp); Gram-positive organisms Staphylococcus aureus ATCC 25213, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis) and a fungus (Candida albicans). Agar well diffusion and broth dilution methods were used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at concentrations of 512mg/ml to 4mg/ml. All the organisms except Candida albicans were susceptible to the extracts obtained from the traditional method. The squeezed-leaf juice of Kalanchoe crenata was the most active one with MIC of 8 mg/ml against Pseudomonas aeruginosa, Klebsiella pneumoniae and Bacillus subtilis, 32 mg/ml against Shigella flexneri, 64 mg/ml against Escherichia coli and 128 mg/ml against the control strain Staphylococcus aureus while its MBC is 256 mg/ml against these organisms except Bacillus subtilis and Klebsiella pneumoniae. The Gram-positive organisms were more sensitive to the methanol and local gin-extract of Bryophyllum pinnatum. Extracts from other solvents showed moderate to weak 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.     

Antimicrobial Activity and Phytochemical Study of Vernonia Glabra (Steetz) Oliv. & Hiern. in Kenya

Infectious diseases are prevalent and life threatening in Kenya. Majority of the sick are seeking herbal remedies in search of effective, safe, and affordable cure. This project aims to investigate the antimicrobial activity and presence of active phytochemical compounds in different parts of Vernonia glabra; a plant used by herbalists in various regions of Kenya, for the treatment of gastrointestinal problems. The plant sample was collected in January 2010 in Machakos, and different parts dried at room temperature under shade, ground into powder and extracted in Dichloromethane: Methanol in the ratio 1:1, and water. These crude extracts were tested against Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger for antimicrobial activity using disc diffusion technique. Minimum inhibitory concentrations (MICs) for active crude extracts were done using disc diffusion technique after the failure of agar and broth dilution methods. It was observed that the organic crude extracts of flower, leaf, stem, root, and/or entire plant, showed activity against at least one of the four micro-organisms screened, and at concentrations lower than the aqueous crude extracts. Organic crude extract of the leaf showed the highest activity against Staphylococcus aureus (mean inhibition zone of 1.85), recording higher activity than the commercially used standard antibiotic (Streptomycin mean inhibition zone of 1.30). The organic crude extract of flower showed significant activity only against S. aureus, with the lowest MIC of 1.5625 mg/100µl, compared to streptomycin with M.I.C of 6.25 mg/100µl. Thin Layer Chromatography-Bioautography Agar-Overlay showed that, flower alkaloids (50% active), root sapogenins (43.8% active), and root terpenoids (38.5% active) were identified as the potential antibacterial compounds against S. aureus. These results suggest that, V. glabra contains phytochemicals of medicinal properties and justify the use of V. glabra in traditional herbal medicine for the treatment of microbial based diseases. However, research on toxicity which is missing in this study is recommended for V. glabra in order to verify, validate and document the safety of this medicinal plant to the society.     

Antibacterial Activity of a Cardanol from Thai Apis mellifera Propolis

Background: Propolis is a sticky, dark brown resinous residue made by bees that is derived from plant resins. It is used to construct and repair the nest, and in addition possesses several diverse bioactivities. Here, propolis from Apis mellifera from Nan province, Thailand, was tested for antibacterial activity against Gram^+ve (Staphylococcus aureus and Paenibacillus larvae) and Gram^-ve (Escherichia coli) bacteria.Materials and methods: The three bacterial isolates were confirmed for species designation by Gram staining and analysis of the partial sequence of 16S rDNA. Propolis was sequentially extracted by methanol, dichloromethane and hexane. The antibacterial activity was determined by agar well diffusion and microbroth dilution assays using streptomycin as a positive control. The most active crude extract was further purified by quick column and adsorption chromatography. The apparent purity of each bioactive fraction was tested by thin layer chromatography. The chemical structure of the isolated bioactive compound was analyzed by nuclear magnetic resonance (NMR).Results: Crude methanol extract of propolis showed the best antibacterial activity with a minimum inhibition concentration (MIC) value of 5 mg/mL for S. aureus and E. coli and 6.25 mg/mL for P. larvae. After quick column chromatography, only three active fractions were inhibitory to the growth of S. aureus and E. coli with MIC values of 6.25 and 31.3 µg/mL, respectively. Further adsorption chromatography yielded one pure bioactive fraction (A1A) with an IC₅₀ value of 0.175 µg/mL for E. coli and 0.683 µg/mL for P. larvae, and was determined to be cardanol by NMR analysis. Scanning and transmission electron microscopy analysis revealed unusual shaped (especially in dividing cells), damaged and dead cells in cardanol-treated E. coli.Conclusion: Thai propolis contains a promising antibacterial agent.     

Antimicrobial Activity of Carpolobia Lutea Extracts and Fractions

Carpolobia lutea (G. Don) (Polygalaceae) is a tropical medicinal plant putative in traditional medicines against gonorrhea, gingivitis, infertility, antiulcer and malaria. The present study evaluated the antimicrobial, antifungal and antihelicobacter effects of extracts C. lutea leaf, stem and root. The extracts were examined using the disc-diffusion and Microplates of 96 wells containing Muller-Hinton methods against some bacterial strains: Eschericia coli (ATCC 25922), E. coli (ATCC10418), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Staphyllococus aureus (ATCC 6571), Enterococcus faecalis (ATCC 29212) and Bacillus subtilis (NCTC 8853) and four clinical isolates: one fungi (Candida albican) and three bacteria (Salmonella, Sheigella and staphylococcus aureus). The Gram-positive bacteria: Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Bacillus subtilis (ATCC 19659) and the Gram-negative bacteria: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Cândida albicans (ATCC 18804) and Helicobacter pylori (ATCC 43504). Some of these extracts were found to be active against some tested strains but activity against H. pylori was >1000mg/ml and good fungistatic activity against C. albican. The MIC against C. albican is in the order n-HF > CHF > ETF= EAF.The order of potency of fraction was the ethanol root > n-HF leaf > ethanol fraction stem > chloroform fraction leaf = ethyl acetate fraction leaf. Polyphenols were demonstrated in ethanol fraction, ethyl acetate fraction, crude ethyl acetate extract and ethanol extract, respectively. These polyphenols isolated may partly explain and support the use of C. lutea for the treatment of infectious diseases in traditional Ibibio medicine of Nigeria.     

Anti-Inflammatory and Antimicrobial Activities of Hippocratea Indica Root Bark and Poga Oleosa Fruits

The methanolic extracts of Hippocratea indica root bark and Poga oleosa fruits were investigated for anti-inflammatory and antimicrobial activities. Both extracts inhibited carrageenan-induced paw oedema significantly in rats in a dose-dependent manner in 4 h. H. indica inhibited oedema significantly at the minimal dose (125 mg/ml, p< 0.05) from 2 h onward, and gave 100% inhibition in 4 h. at 250 mg/kg. It was shown to be a more potent anti-inflammatory agent than P. oleosa. Also, H. indica extract exhibited greater antimicrobial activity against tested bacteria, with Staphylococcus aureus being the most susceptible bacterium (MIC, 16 mg/ml). Both plants were inactive against Candida albicans. These results confirm the anti-inflammatory and antibacterial activities of the two plants.     

Qualitative Phytochemical Screening and In Vitro Antimicrobial Effects of Methanol Stem Bark Extract of Ficus Thonningii (Moraceae)

The methanolic stem bark extract of Ficus thonningii (Moraceae) was subjected to preliminary phytochemical screening and in vitro antimicrobial tests. The phytochemical tests was carried out using standard methods of analysis and these investigations revealed the presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial activity of the plant extract was assayed using the agar plate disc diffusion and nutrient broth dilution techniques. Test micro organisms were: Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Salmonella typhi (Gram-negative), Staphylococcus aureus and Streptococcus spp. (Gram-positive). The extracts inhibited the growth of all the test organisms at different concentrations especially against Pseudomonas aeruginosa and Streptococcus spp. which had mean inhibition zone of 33.33±7.33 mm and 32.33±2.51 mm respectively. The results showed the MIC of 10 mg ml⁻¹ against pseudomonas and 1.25 against remaining organisms tested. The MBC against Staphylococcus aureus was 2.5 mg ml⁻¹ and that of Streptococcus spp. was found to be 0.625mg ml⁻¹. The extracts showed varied inhibitory activity against the organisms studied.     

Biological Activities of Schefflera Leucantha

This study investigated various biological activities of the ethanolic extract of dried ground leaves of Schefflera leucantha Viguier (Araliaceae). The extract possessed very low cytotoxicity to brine-shrimp with the LC₅₀ of 4,111.15µg/ml; the significant antioxidant activity on DPPH with the EC₅₀ of 71.90µg/ml; the inhibitory activity on mushroom tyrosinase with the IC₅₀ of 10.53mg/ml using the dopachrome microplate-assay. The extract of 5–20mg/ml range in the agar dilution assay were active against various pathogenic microbial (11 species, 11 strains), with the minimum inhibitory concentration (MIC) of 5mg/ml against Clostridium spp.; MIC=10mg/ml against enteropathogens as Bacteroides spp., Enterococcus faecalis ATCC 29212, Lactobacillus spp., Peptococcus spp. and Streptococcus mutans; MIC=10mg/ml against a pneumonia causing bacteria Klebsiella pneumoniae and a dermatopathogen as Propionibacterium acnes; MIC=20mg/ml against dermatopathogens as Staphylococcus aureus ATCC 6538, Streptococcus spp. and Candida albicans ATCC 90028. TLC fingerprints of the specific extracts from the leaf powder exhibited zones of steroids-terpenes and flavonoids. HPLC fingerprint of the flavonoid extract was performed.     

Antimicrobial Activity of Essential Oils of Xylopia Aethiopica

Xylopia aethiopica is a medicinal plant of great repute in West Africa which produces a variety of complex chemical compounds. The fresh and dried fruits, leaf, stem bark and root bark essential oils showed various degrees of activity against the Gram positive bacteria, Bacillus subtilis and Staphylococcus aureus, the Gram negative bacteria Pseudomonas aeruginosa and the yeast-like fungus Candida albicans, using the cup plate method,. However, none of the oils showed activity against Escherichia coli.     

Antimicrobial Activity of the Solvent Fractions from Bulbine Natalensis Tuber

Bulbine natalensis Baker has been acclaimed to be used as an antimicrobial agent in the folklore medicine of South Africa without scientific evidence to substantiate or refute this claim. In view of this, the in vitro antimicrobial activity of solvent fractions (ethanol, ethyl acetate, n-butanol and water) from Bulbine natalensis Tuber against 4 Gram positive and 12 Gram negative bacteria as well as 3 fungal species were investigated using agar dilution. The ethanolic extract, n-butanol and ethyl acetate fractions inhibited 75, 87.5 and 100% respectively of the bacterial species in this study. The ethanolic, n-butanol and ethyl acetate fractions produced growth inhibition at MIC range of 1–10, 3–10 as well as 1 and 5 mg/ml respectively whereas the water fraction did not inhibit the growth of any of the bacterial species. Again, it was only the ethyl acetate fraction that inhibited the growth of Shigelli flexneri, Staphyloccus aureus and Escherichia coli. The ethanolic, ethyl acetate and n-butanolic fractions dose dependently inhibited the growth of Aspergillus niger and A. flavus whereas the water fraction produced 100% growth inhibition of the Aspergillus species at all the doses investigated. In contrast, no growth inhibition was produced on Candida albicans. The growth inhibition produced by the solvent fractions of B. natalensis Tuber in this study thus justifies the acclaimed use of the plant as an antimicrobial agent. The ethyl acetate fraction was the most potent.     

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.     

Opsonic activity in human serum chelated with ethylene glycoltetra-aectic acid

The influence of the alternative pathway of complement activation on opsonization of S. aureus, E. coli and Candida albicans for phagocytosis was selectively studied by chelating serum with 10 mM EGTA and 10 mM MgC1₂. Opsonic activity of the chelated serum depended on the alternative pathway of complement activation. The classical pathway was inhibited. There was no phagocytosis of S. aureus in chelated normal serum, suggesting that activation of complement activity by the classical pathway is necessary for opsonization of this micro-organism. In control experiments when opsonization of S. aureus was accomplished by IgG separated from hyperimmune serum, without the requirement of complement activity, there was no inhibition of phagocytosis by EGTA and magnesium chloride. E. coli and C. albicans were opsonized in chelated normal serum, indicating that the alternative pathway of complement activation is involved in opsonization of these micro-organisms.     

The Preliminary Assessment of Anti-Microbial Activity of HPLC Separated Components of Kirkia Wilmsii

Background

Most communities in developing countries rely on traditional medicines for the treatment of diseases. In South Africa, the Limpopo province, within the Lebowakgomo district, uses tuberous roots of Kirkia wilmsii, after infusion in water for the treatment of a wide range of diseases by Sotho communities.

Materials and Methods

The main objective of the study was to assess the anti-microbial activity of separated aqueous components of the Kirkia wilmsii tuberous roots. The clear aqueous extracts that were obtained after a 0.45 µm membrane filtration (Millipore Millex-HV Hydrophillic PVDF filter), were then injected into a preparative high performance liquid chromatography instrument in which pure components, as shown by peaks, were collected and evaluated for anti-microbial activity against a range of microorganisms.

Results

The eight separated components were obtained, out of which four components showed anti-microbial activity (AMA). The freeze dried components were re-dissolved in deionised water and then evaluated for AMA against Vibrio cholerae, Shigella dysenteriae, Aeromonas hydrophilia, Salmonella typhi Proteus mirabilis, Escherichia coli, Staphylococcus aureus, Candida albicans and Enterobacter aerogenes. Component one exhibited antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophilia, Salmonella typhi, Proteus mirabilis, Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration (MIC), of 3.445 mg/ml. Component five was only active against Proteus mirabilis with a MIC of 0.08 mg/ml. Component 7, was active against Shigella dysenteriae, Staphylococcus aureus and Escherichia coli with a MIC of 0.365 mg/ml against both Shigella dysenteriae and Staphylococcus aureus and 0.091 mg/ml against Escherichia coli. Component 8, was active against Shigella, Aeromonas hydrophilia, Salmonella, Proteus mirabilis, Escherichia coli with a MIC of 155 mg/ml.

Conclusion

Only four out of eight aqueous extracts showed AMA against both gram negative and positive bacteria and showed no AMA against Candida albicans, Enterobacter aerogenes and Vibrio cholerae. Therefore the Kirkia wilmsii plant root may be used as a broad spectrum antibiotic.     

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.     

A comparative study of antimicrobial properties of crustinPm1 and crustinPm7 from the black tiger shrimp Penaeus monodon

Several isoforms of crustin have been identified in the black tiger shrimp Penaeus monodon. These cationic cysteine-rich antimicrobial peptides contain a single whey acidic protein (WAP) domain at the C-terminus and exhibit antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigate the binding properties and antimicrobial actions of crustinPm1 and crustinPm7, the two most abundant crustin isoforms found in the haemocyte of P. monodon. Previously, crustinPm1 showed strong inhibition against Gram-positive bacteria, whilst crustinPm7 acted against both Gram-positive and Gram-negative bacteria. A binding study showed that both crustins can bind to Gram-positive and Gram-negative bacterial cells. Enzyme-linked immunosorbent (ELISA) assay suggested that crustins bind to the cell wall components, lipoteichoic acid (LTA) and lipopolysaccharide (LPS) with positive cooperativity of Hill slope (H) > 2. This indicates that at least two molecules of crustins interact with one LTA or LPS molecule. In addition, both crustins can induce bacterial agglutination and cause inner membrane permeabilization in Escherichia coli. Scanning Electron Microscopy (SEM) revealed the remarkable change on the cell surface of Staphylococcus aureus, Vibrio harveyi and E. coli after the bacteria were treated with the recombinant crustinPm7. Meanwhile, crustinPm1 can cause a visible change on the cell surface of S. aureus and E. coli only. This is in agreement with the fact that crustinPm1 has shown no antimicrobial activity against V. harveyi. It is likely that the antimicrobial activity of crustins mainly relies on their ability to agglutinate bacterial cells and to disrupt the physiochemical properties of bacterial surface.