A range of model plants was used for these tests. Thereby due to their relevance in
the production of food and feed, particular emphasis was set on edible plants.
Examples therefore are vegetables such as tomato [37–40], cucumber [41–43],
bean [39], lettuce [37, 39, 40, 44–49], pea [40], cabbage [50], carrot [51], onion
[40, 52], garden cress [35, 53–55], and radish [36, 47, 56–59] treated with NSAIDs,
antibiotics, antidepressants, PAR, carbamazepine, or personal care products as well
as maize [40], wheat [37], barley [58], sorghum [40], and millet [40] grown in
diclofenac-containing medium.
Another approach for investigating the interaction of plants with xenobiotics is
the use of cell cultures [28, 36, 42, 51, 56–58, 60–63]. Major advantage of this
experimental setup is the fact that cultivating and also incubating cell cultures is
affected with less effort than growing whole plants (or at least plantlets). On the other
hand, cell cultures do not allow to study transformation phenomena such as a (timedependent) monitoring of parent drug and metabolite concentrations in different
plant parts.
2.2 Harvesting and Extraction
Depending on the study layout (but of course also on the plant model used), the
period between the start of a growing experiment and the final harvesting of the
plants ranged between a few days (for an example, see [35, 53, 54]) and several
months (for an example, see [38, 45, 52]). Whereas in the case of plant cell
experiments there is no other choice than using the whole cells for analysis, the
situation is different when growing full plants. In this case, depending on the size of
the harvested plantlet, it could be divided into several distinct plant parts (commonly
roots, stem, leaves, bulbs, or fruit) which were subsequently extracted and analyzed
separately. This allowed judging the translocation of the parent drug and the
metabolites into different plant compartments. In a series of works, the latter was
also studied as a function of time, harvesting plants at several time points and
studying the time-resolved distribution of parent drug(s) as well as metabolites
within the plant parts investigated.
In most cases, parent drugs and/or metabolites were recovered from plant material
and cell cultures by simple and straightforward extraction with appropriate solvents.
Plant material was either directly homogenized (e.g., using an Ultra-Turrax – for
exemplary papers, see [53–55]) or freeze-dried and grinded to form a fine powder
with subsequent solvent extraction (e.g., using an ultrasound bath – for exemplary
papers, see [38, 41] or accelerated solvent extraction [37, 43]). For a cleanup and a
further preconcentration step, extracts were subjected to a solid phase extraction
(SPE) procedure. For the parent drugs, SPE provided acceptable preconcentration
factors. For some of the more polar substances such as the sugar-containing metabolites formed from diclofenac (DCF), naproxen (NPX), ketoprofen (KPF), and
mefenamic acid in cress, only a very limited preconcentration effect could be
Analytical Approaches for the Determination and Identification of Drug. . .
499
the production of food and feed, particular emphasis was set on edible plants.
Examples therefore are vegetables such as tomato [37–40], cucumber [41–43],
bean [39], lettuce [37, 39, 40, 44–49], pea [40], cabbage [50], carrot [51], onion
[40, 52], garden cress [35, 53–55], and radish [36, 47, 56–59] treated with NSAIDs,
antibiotics, antidepressants, PAR, carbamazepine, or personal care products as well
as maize [40], wheat [37], barley [58], sorghum [40], and millet [40] grown in
diclofenac-containing medium.
Another approach for investigating the interaction of plants with xenobiotics is
the use of cell cultures [28, 36, 42, 51, 56–58, 60–63]. Major advantage of this
experimental setup is the fact that cultivating and also incubating cell cultures is
affected with less effort than growing whole plants (or at least plantlets). On the other
hand, cell cultures do not allow to study transformation phenomena such as a (timedependent) monitoring of parent drug and metabolite concentrations in different
plant parts.
2.2 Harvesting and Extraction
Depending on the study layout (but of course also on the plant model used), the
period between the start of a growing experiment and the final harvesting of the
plants ranged between a few days (for an example, see [35, 53, 54]) and several
months (for an example, see [38, 45, 52]). Whereas in the case of plant cell
experiments there is no other choice than using the whole cells for analysis, the
situation is different when growing full plants. In this case, depending on the size of
the harvested plantlet, it could be divided into several distinct plant parts (commonly
roots, stem, leaves, bulbs, or fruit) which were subsequently extracted and analyzed
separately. This allowed judging the translocation of the parent drug and the
metabolites into different plant compartments. In a series of works, the latter was
also studied as a function of time, harvesting plants at several time points and
studying the time-resolved distribution of parent drug(s) as well as metabolites
within the plant parts investigated.
In most cases, parent drugs and/or metabolites were recovered from plant material
and cell cultures by simple and straightforward extraction with appropriate solvents.
Plant material was either directly homogenized (e.g., using an Ultra-Turrax – for
exemplary papers, see [53–55]) or freeze-dried and grinded to form a fine powder
with subsequent solvent extraction (e.g., using an ultrasound bath – for exemplary
papers, see [38, 41] or accelerated solvent extraction [37, 43]). For a cleanup and a
further preconcentration step, extracts were subjected to a solid phase extraction
(SPE) procedure. For the parent drugs, SPE provided acceptable preconcentration
factors. For some of the more polar substances such as the sugar-containing metabolites formed from diclofenac (DCF), naproxen (NPX), ketoprofen (KPF), and
mefenamic acid in cress, only a very limited preconcentration effect could be
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