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China R.,University of Calcutta | Mukherjee S.,University of Calcutta | Sen S.,University of Calcutta | Bose S.,University of Calcutta | And 4 more authors.
Microbiological Research | Year: 2012

Polyphenolic extracts (PE) of edible flower of Sesbania grandiflora were tested to evaluate its antimicrobial effect against some common pathogenic bacteria and growth promoting property against probiotic organism Lactobacillus acidophilus. The antimicrobial activity of S. grandiflora flower PE against selected pathogens was evaluated using both in vitro and in situ methods. In vitro studies suggested that PE has inhibitory effect against Staphylococcus aureus, Shigella flexneri 2a, Salmonella Typhi, Escherichia coli and Vibrio cholerae. The gram-positive organism S. aureus was the most sensitive organism to PE and minimum inhibitory concentration (MIC) was found to be 0.013. mg/mL where as the MIC of PE against V. cholerae was the highest (0.25. mg/mL). On the other hand PE showed growth promoting effect on the common probiotic bacterium L. acidophilus. The major finding was that S. grandiflora PE induced a significant biomass increase of L. acidophilus grown in liquid culture media. PE showed reduction of S. aureus growth in food (fish) during storage at 10 °C. High performance liquid chromatography analysis showed that rutin, a major flavonoid of the PE diminished in the culture medium MRS broth with the growth of L. acidophilus. © 2012 Elsevier GmbH.

Mukherjee S.,University of Calcutta | Koley H.,National Institute of Cholera and Enteric Disease NICED | Barman S.,National Institute of Cholera and Enteric Disease NICED | Mitra S.,National Institute of Cholera and Enteric Disease NICED | And 4 more authors.
Journal of Medicinal Food | Year: 2013

In this study, the extract of a green leafy vegetable Oxalis corniculata (Oxalidaceae) was evaluated for its in vitro antibacterial and in vivo anti colonizing effect against common intestinal pathogenic bacteria. Methanolic extract (80%) of Oxalis corniculata (Oxalidaceae) leaf contained a polyphenol content of 910 mg gallic acid equivalent per gram of dry weight and the yield was 8%. The flavonoid content was 2.353 g quercetin equivalent per 100 g of the extract. In vitro studies indicated that the extract inhibited numerous pathogenic bacteria like Staphylococcus aureus (ATCC 25922), Escherichia coli (ATCC 25923), Shigella dysenteriae 1 (NT4907), Shigella flexneri 2a (2457T), Shigella boydii 4 (BCH612), and Shigella sonnie phase I (IDH00968). The minimum inhibitory concentration (MIC) against E. coli (ATCC 25923) was minimal (0.08 mg/mL), whereas MIC against S. flexneri 2a (2457T) was higher (0.13 mg/mL). A suckling mouse model was developed which involved challenging the mice intragastrically with S. flexneri 2a (2457T) and S. dysenteriae 1 (NT4907) to study the anticolonization activity. It was revealed that the extract was more potent against S. dysenteriae 1 (NT4907) as compared to S. flexneri 2a (2457T). It was also found that simultaneous administration of extract along with bacterial inoculums promoted good anticolonization activity. Significant activity was observed even when treated after 3 h of bacterial inoculation. © Mary Ann Liebert, Inc., and Korean Society of Food Science and Nutrition.

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