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Title: Antiviral activity of ingredients in the fruit rind of Punica granatum L.
Author: Corao, G.
Awarding Body: University of Brighton
Current Institution: University of Brighton
Date of Award: 2001
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The research described in this thesis concerns the antiviral activity found in the fruit rind of pomegranate, Punica granatum L., as reported by Stewart et al., (1998). The active ingredients were not identified. Chromatographic separation of pomegranate rind extract (PRE) by HPLC provided fractions for antiviral testing. The process involved a large number of samples, which required an accurate, inexpensive, fast and easy method to detect active antiviral fractions. The method developed was based on phage lytic cycle technology. Pseudomonas aeruginosa 10116-195 and Escherichia coli 13706-B1 bacteriophage were used to investigate the virucidal activity of different fractions originating from chromatographic separation, in combination with ferrous sulphate. After 3 min of bacteriophage contact with each fraction, corresponding host bacteria were added and the mixture placed onto a 96-well microtitre plate filled with appropriate media and the plate incubated overnight at 37 °C. The assay was recorded as antiviral where the well showed bacterial growth (cloudy). JSD solution, a combination of PRE and ferrous sulphate, was use as control. Activity comparisons were made with known compounds. Three fractions collected from preparative HPLC were found with antiviral activity. The active fractions were isolated, purified and characterised by TLC, HPLC, mass spectrometry, pH dependency, and chemical stability. A tentative identification of punicalagin as the active polyphenol was also made. The phage lytic method was used to screen seventy-four extracts from twelve Amazonian plant species; thirteen were found with antiviral activity. The successful screening of this large number of samples was enabled because of the high accuracy and simplicity of the method. Electron microscopy was used to demonstrate the destructive capability of PRE active fractions when mixed with ferrous sulphate solution. Mechanism of action studies indicated potentiation of PRE activity with acid pH and ferrous sulphate. Antiviral effects are proposed to arise from free radical production and possible specific inhibition of enzymes associated with bacteriophage activity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available