Anna Piovan

Melatonin in plants.

A widespread occurrence of melatonin in plant kingdom has been reported. The circadian rhythm in the level of melatonin observed in both unicellular algae and higher plants, suggests a role in regulation of photoperiodic and rhythmic phenomena, i.e. a similar function for melatonin in both plants and animals. Evidence has been obtained for a role of melatonin in plant morphogenesis, but more research is needed to ascertain other suggested physiological roles in higher plants (seed dormancy regulation, radical scavenger activity, interaction with calmodulin) as well the ecological significance of the high melatonin levels recorded in alpine plants. Setting-up more reliable analytical methods for melatonin detection and quantification is a basic requirement to get more insight into melatonin roles in plant physiology and ecology.

Study of dynamic accumulation of secondary metabolites in three subspecies of Hypericum perforatum.

St. Johns Wort extracts are used for the treatment of mild to moderately severe depression, and their composition and standardization have been thoroughly investigated. Standardization of St. Johns Wort extracts has to cope with several factors that affect the phytochemical profile of the plant, with geographic location, seasonal variations and subspecies all being important. To address this issue, three different subspecies of Hypericum perforatum L. were profiled in relation to different maturation phases, evaluating the variations in the context of the major secondary metabolites from this plant. HPLC analysis indicated that H. perforatum subsp. perforatum is richer in secondary metabolites than the other subspecies, and that the three subspecies show a different profile during the developmental stages. Hypericins, hyperforins and flavonoids peak at quite different stages, and the standardization of Hyperici extracts based only on the contents of hypericin is not adequate to guarantee batch reproducibility of the extracts.

Characterization of the anthocyanins of Catharanthus roseus (L.) G. Don in vivo and in vitro by electrospray ionization ion trap mass spectrometry

The power of direct infusion electrospray (ESI) mass spectrometry and ion trap multiple mass spectrometry (MS/MS) were applied to the detection and identification of the anthocyanic compounds of Catharanthus roseus (L.) G. Don. Cell suspensions of C. roseus, fresh flowers from both in vitro regenerated and field-grown plants, were comparatively examined. The anthocyanic extracts were analyzed by positive-ion electrospray ionization mass spectrometry and collision experiments were performed on molecular ions by means of ion trap facilities. In parallel, classical approaches such as thin layer chromatography (TLC) and UV/Vis spectroscopy were undertaken. Petunidin, malvidin and hirsutidin, already known in the literature, were identified as aglycones. Three 3-O-glucoside derivatives, supposed to be present on the basis of literature data, were also identified. Moreover, three 3-O-(6-O-p-coumaroyl)glucosides were identified for the first time in this species. Using the direct ESI-MS/MS approach, the mass spectra of all the anthocyanic compounds present in the extracts can be obtained, even of those occurring in traces and not detectable by TLC. The three extracts investigated showed the same qualitative anthocyanic profile, but large quantitative differences.

Production of anthocyanins by Catharanthus roseus

A stable cell suspension line of Catharanthus roseus producing anthocyanin was obtained. In this strain it was found that approximately 30% of cells regularly accumulated these metabolites and that anthocyanin accumulation occurred between the second half of log phase and the stationary phase of the culture growth cycle. The anthocyanins in the suspension cultures were compared with those biosynthetized in the flowers both of regenerated by somatic embryogenesis and field-grown plants. Six anthocyanins were identified in all the examined samples, three 3-O-glucosides and three 3-O-(6-O-p-coumaroyl) glucosides of petunidin, malvidin and hirsutidin. The hirsutidin coumaroyl glucoside has not been reported previously, and was predominat in all samples. The anthocyanin relative content was similar for cell suspensions and flowers from regenerated plants but different from field-grown plant flowers; instead, the total content was almost the same for the two flower types and higher compared to suspension culture content.

Anthocyanins in Catharanthus roseus in vivo and in vitro: a review

The production of anthocyanin in Catharanthus roseus flowers from both field-grown and regenerated by somatic embryogenesis plants and cell cultures was described. The anthocyanins were identified as the 3-O-glucosides, and the 3-O-(6-O-p-coumaroyl) glucosides of hirsutidin, malvidin and petunidin, respectively both in vivo and in vitro. The influence of environmental conditions on in vitro anthocyanin accumulation is described. The relationship between in vivo and in vitro anthocyanin production is discussed.

Unilateral mydriasis due to Angel's Trumpet

Introduction. There are many causes of bilateral and unilateral mydriasis. Common garden plants, such as Brugmansia (Angels trumpet), contain tropane alkaloids. Case Report. An 11–year-old girl was brought to the Emergency Department because of discomfort and difficulty with near vision in the left eye, accompanied by unilateral mydriasis (pupil approximately 8 mm, unresponsive to both papillary light reflex and accommodation reflex). The consensual papillary light reflex of the right eye, the anterior chambers, the fundi, and the extraocular movements were intact. The history revealed that she had been playing in the garden and had just touched “a nice pink flower, similar to a trumpet.” Treatment was symptomatic and supportive, and the anisocoria resolved 48 hours after exposure. Morphological and chemical investigations showed high amounts of parasympatholytic tropane alkaloids in a corolla area rich in Dargendorff-positive glandular hairs. Discussion. Simple topical exposure to the flowers of Angels trumpet, without instillation of plant sap into the eye, can produce self-limited unilateral mydriasis. Conclusions. This case adds to the differential diagnosis of acute anisocoria in otherwise healthy children. An accurate and detailed history will avoid unnecessary and expensive diagnostic tests. It is important for parents and garden suppliers have information about the potential adverse effects after handling Angels trumpet plants.

Fucoxanthin from Undaria pinnatifida: Photostability and Coextractive Effects

Fucoxanthin is one of the most abundant carotenoids and possesses a number of beneficial medicinal qualities which include its anti-oxidant, anti-obesity and anti-cancer properties. In this study, the photostability of fucoxanthin in extracts with different chemical profiles was studied. The extracts were obtained from Undaria pinnatifida, a seaweed rich in this carotenoid, using conventional liquid solvent extraction procedures and the QuEChERS method. All the extracts contained all-trans-fucoxanthin as the major compound. Conventional procedures produced a fucoxanthin purity of lower than 50%, whereas after liquid-liquid partition, PSA cleanup, and PSA and GCB cleanup (QuEChERS method) fucoxanthin purity increased to 70%, 86%, and 94%, respectively. Although in the acetone extract the initial content of fucoxanthin was the highest, results demonstrate that coextractives play an important role in enhancing the rate of photodegradation. After light exposure, the conventional extracts lost around 90% of the initial fucoxanthin content. On the other hand, the extracts obtained by the QuEChERS method showed significantly higher light stability than the conventional extracts. These results suggest that the QuEChERS method could be used and further improved to obtain more purified and stable extracts for fucoxanthin from U. pinnatifida.

Somatic embryogenesis and indole alkaloid production in Catharanthus roseus

ABSTRACT A new protocol to obtain an embryogenic cell line from cultured seedling explants of Catharanthus roseus is described. In order to assess the relationship between tissue differentiation and secondary metabolite biosynthesis, the biosynthetic capabilities (alkaloid production) of an embryogenic cell line and two non-embryogenic C. roseus strains were comparatively examined. Faster cell growth rate was associated with higher alkaloid production in the embryogenic cell line. The kinetics of ajmalicine and serpentine production by the three cell lines is also reported.

Production of coumarin compounds by Haplophyllum patavinum in vivo and in vitro

Abstract Native plants, calli and suspension cultures of Haplophyllum patavinum were found to produce several coumarin compounds, eight of which were identified as umbelliferone, scopoletin, 7-isoprenyloxycoumarin, umbelliprenin, osthenol, columbianetin, angelicin and psoralen. Umbelliferone, angelicin and psoralen were found both in plant organs and in tissue cultures, scopoletin and umbelliprenin only in vivo , osthenol, 7-isoprenyloxycoumarin and columbianetin only in vitro conditions. The coumarin production in vitro was strongly affected by the cell strain. The co-occurrence of the linear and the angular furanocoumarins, psoralen and angelicin, had never been previously reported in the genus Haplophyllum .

Morpho-physiological effects of ibuprofen on Scenedesmus rubescens

The pollution of aquatic bodies by drugs is an emerging environmental problem, because of their extensive use in animal and human context. Ibuprofen, 2-[4-(2-methylpropyl)phenyl]propanoic acid, is the non-steroidal anti-inflammatory drug mainly present both in wastewater and in rivers and lakes in Europe. Since in literature there is little information about the effects of ibuprofen on microalgae, in this paper we presented the results on the effects of this molecule at different concentrations (62.5μgL(-1), 250μgL(-1) and 1000μgL(-1)) on cultures of the freshwater microalga Scenedesmus rubescens (P.J.L. Dangeard) E. Kesslet et al. Ibuprofen effects on the alga were assayed at first through analyses of the growth curve. Moreover, analyses of cell morphology, ultrastructure, and photosynthetic pigments were additionally performed. The first negative effect of the drug was on the microalga growth, suggesting a drug action dose-dependent mechanism type, more evident at the concentration of 1000μgL(-1) ibuprofen and in the last phase of the growth curve. In support of this, following ibuprofen exposure, the cells exhibited morphological and ultrastructural alterations, mainly consisting in large cytoplasmic inclusions, probably of lipids and/or carotenoids. The decrease of chlorophyll amounts and, on the contrary, the increase of carotenoids were correlated with a stressful condition induced by drug.