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- 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.
- In vitro propagation of Drosera intermedia in a single stepPublication . Grevenstuk, Tomás; Coelho, Natacha; Gonçalves, Sandra; Romano, AnabelaA simple and efficient protocol for the micropropagation of Drosera intermedia, using cultures initiated from in vitro produced seedlings, is described. Shoot proliferation was significantly influenced by Murashige and Skoog (MS) macronutrient concentration, showing higher multiplication rates for ¼ MS (the lowest concentration), but was not affected by the addition of 0.1 mg dm-3 kinetin. In all cases a multiplication percentage above 90 % was recorded. High rooting percentages (up to 100 %) were obtained in multiplication phase on ¼ MS medium without growth regulators. In average 15.8 plantlets per initial shoot was produced after 8 weeks of culture. All plantlets were successfully acclimatized to ex vitro conditions, exhibiting normal development.