Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Inhibitory activity of plumbagin produced by Drosera intermedia on food spoilage fungiPublication . Grevenstuk, Tomás; Gonçalves, Sandra; Domingos, Telma; Quintas, Célia; van der Hooft, Justin J. J.; Vervoort, Jacques; Romano, AnabelaBackground: The aim of this study was to investigate the growth-inhibiting efficacy of Drosera intermedia extracts (water, methanol and n-hexane) against four food spoilage yeasts and five filamentous fungi strains responsible for food deterioration and associated with mycotoxin production, in order to identify potential antimycotic agents. Results: The n-hexane extract showed a broad activity spectrum against all tested microorganisms, followed, in activity, by the methanol and water extracts. The major component of the n-hexane extract was purified using a solid-phase extraction column and identified as plumbagin. Results show that high-purity plumbagin can be produced from D. intermedia cultures following a simple and effective isolation procedure. A sample of purified plumbagin was tested against the same panel of microorganisms and high growth-inhibiting capacity was observed. Minimum inhibitory concentrations less than 2 μgmL−1 were obtained against the filamentous fungi. In the case of the species Aspergillus fumigatus, A. niger and A. flavus, activities comparable to miconazole were obtained. Conclusion: The results obtained provided evidence of the antimycotic activity of plumbagin, suggesting that D. intermedia could be the source of an interesting compound for the food industry as an alternative to preservatives.
- Plumbagin recovery in field specimens of Drosophyllum lusitanicum (L.) LinkPublication . Grevenstuk, Tomás; Gonçalves, Sandra; Nogueira, José Manuel F.; Romano, AnabelaThe naphthoquinone plumbagin has a broad spectrum of biological activities. The aim of this study was to investigate the efficiency of two extraction methods (Soxhlet and ultrasound-assisted extraction) and three solvents (methanol, chloroform and hexane) to recover plumbagin from fresh and dried tissues of field specimens of Drosophyllum lusitanicum (L.) Link. The highest extraction yields were obtained with methanol as solvent and using fresh plant material. The obtained extracts were analysed by gas chromatography with mass spectrometric detection and plumbagin was the major compound present. Plumbagin was quantified in the extracts using the external standard methodology. The results obtained showed that the best recoveries of plumbagin were attained using fresh plant material and there were no significant differences between Soxhlet and ultrasound-assisted extraction. Moreover, hexane proved to be the more appropriate solvent for the extraction of plumbagin, providing high recoveries and the most concentrated extracts, yielding 2.42 mg of plumbagin per gram of plant material with the highest degree of purity. This method is a simple and efficient one to extract large amounts of plumbagin from D. lusitanicum field specimens.