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Phytochemical studies and biological activity of carnivorous plants from the Mediterranean region
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Abstract(s)
In this thesis several studies were conducted with four carnivorous plant species which
occur on Portuguese territory: Pinguicula lusitanica, Pinguicula vulgaris, Drosera
intermedia and Drosera rotundifolia. Most habitats of these plants are threatened and
natural populations are scarce, therefore micropropagation protocols were developed to
produce biomass for the subsequent studies. Efficient micropropagation protocols were
developed for P. lusitanica and D. intermedia enabling large scale biomass production,
while protocols for the other two species have still to be optimized (in Chapter 2). The
in vitro established cultures represent active germplasm collections of Portuguese
natural populations and contribute therefore for their conservation. In Chapter 3 extracts
prepared from micropropagated plant material were analyzed using state of the art
HPLC-ESI-MS and HPLC-SPE-NMR equipment which enabled the identification of
the major secondary metabolites produced by P. lusitanica and D. intermedia, directly
from essentially crude extracts. The metabolites identified in P. lusitanica belong to the
iridoid glucosides and caffeoyl phenylethanoid glycosides and D. intermedia was shown
to produce mainly flavonoid glucosides, ellagic acid derivatives and the naphthoquinone
plumbagin. The evaluation of the biological activities of these extracts, compiled in
Chapter 4, showed that the methanol extract of P. lusitanica has considerable
antioxidant activity and that the n-hexane extract of D. intermedia has high
antimicrobial potential. In Chapter 5 a method for the extraction of plumbagin from
micropropagated D. intermedia plants was optimized and its potential as an alternative
for bioprospection evaluated. It was shown that the commercial exploitation of
plumbagin from D. intermedia cultures might be viable and that UAE with n-hexane
followed by an SPE purification step is an efficient procedure for obtaining large
quantities of high purity plumbagin. It is hoped that this study represents an enrichment
of the knowledge on these plants and contributes to their conservation and valorisation.
Description
Tese de doutoramento, Ciências Biotecnológicas (Biotecnologia Vegetal), Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010
Keywords
Pinguicula Drosera Micropropagation Conservation Hyphenated analytical techniques Antioxidant activity Antimicrobial activity Bioprospection Plumbagin