Rosamaria Caniato

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.

Review: Natural Antimalarial Agents (1995-2001)

Malaria is one of the diseases for which even today not many suitable drugs are available. The rapid spread of resistance toward current drugs encourages the study for new active molecules. Ethnobotanical research can be of help to find new leads. Traditional remedies have always been a source of important antimalarial drugs and continue to provide novel and effective treatments, both where pharmaceuticals are not available and also where the disease is highly resistant to commonly prescribed drugs. This article provides a comparative compilation of various studies reported between 1995 and 2001 on natural compounds with antiplasmodial activity, with the goal of providing a basis for further in vitro and in vivo studies, as well as for clinical trials for the development of new antimalarial medicines. Referee: Dr. Robert Verpoorte, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, PO Box 9502, 2300 RA Leiden, The Netherlands

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.

Localization of the cytotoxic hydroperoxyeudesmanolides in Artemisia umbelliformis

Abstract The localization of the cytotoxic hydroperoxyeudesmanolides in Artemisia umbelliformis Lam. (Compositae) was investigated utilizing the histochemical techniques of the colour reactions with acids and with ferrous (II) thiocyanate on samples pre-treated or not with chloroform. All the organs known by chemical analysis to contain sesquiterpene lactones were studied (leaves, twigs, flowers, achenes). A deep red staining with conc. sulphuric acid and a brownish staining with ferrous (II) thiocyanate were observed in the subcuticular space and in the head cells of the biseriate glandular trichomes, and it was shown that for the plant specimens studied these colour reactions are to be considered specific for the sesquiterpenoid hydroperoxides. Based on the results of their localization in the plant as well as on the available experimental evidence on related compounds, a possible ecological significance of the compounds as feeding deterrents and/or allelopathic substances, is suggested.

External antirheumatic and antineuralgic herbal remedies in the traditional medicine of north-eastern italy

The utilization of more than 90 plant species as folk external remedies to treat rheumatic and arthritic diseases is reported, and their possible effectiveness is discussed according to present phytochemical and pharmacological knowledge. Some of the plant species used exhibit skin-irritant properties (protoanemonin, isothiocyanate or allicine yielding plants and species containing capsaicin, oleoresins, volatile oils, resinous principles, alkaloids). The effectiveness of other herbal remedies depends on their content of salicyl derivatives. A considerable number of the plant species utilized contain chemical products (triterpenoid or steroid compounds, alkaloids) for which anti-inflammatory properties have been demonstrated.

Preliminary evaluation of inhibition of matrix-metalloprotease MMP-2 and MMP-9 by Passiflora edulis and P foetida aqueous extracts.

Fruits decoctions of Passiflora edulis and P. foetida var. albiflora were evaluated for the inhibition of activity of gelatinase MMP-2 and MMP-9, two metallo-proteases involved in the tumour invasion, metastasis and angiogenesis. Both water extracts, at different concentrations, inhibited the enzymes.

Chemical diversity of the contents from the secretory structures of Heracleum sphondylium subsp. Sphondylium

Abstract The lipophilic constituents of ‘companion canals’ and vittae co-occurring in fruits of Heracleum sphondylium L. subsp. sphondylium were investigated by microdissection and subsequent analysis by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The chemical composition of the two different types of secretory structures present in the fruits is different The canals, present in all of the aerial vegetative plant parts and in the fruits, are characterized by mono- and sesquiterpenoids, while the vittae, peculiar to the fruits, contain fatty acid aliphatic esters and furocoumarins.

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.

Metals in Undaria pinnatifida (Harvey) Suringar and Sargassum muticum (Yendo) Fensholt edible seaweeds growing around Venice (Italy)

Undaria pinnatifida and Sargassum muticum are the most abundant invasive edible algae species that have colonized the hard substrate around Venice. The contents of Ca, Mg, Fe, Zn, Cu, Mn, Sr, Pb, Cr, Al, Co, Cd, Ni, As, Hg and Ba, were investigated by ICP-MS in seaweed samples collected (Spring 2013) in six different sites of Venice. A correlation analysis of the results was performed. Sargassum muticum exhibited overall higher contents than U. pinnatifida for many of the considered elements. The elemental contents in both species were in ranges comparable to those reported for seaweeds subjected to anthropogenic impact. Considering the French legislation as a working reference for Pb, Cd and inorganic As limits for seaweed for human consumption, the present results pointed out that in both species Pb content was on average higher than the French limits, whereas the Cd and Hg contents were much lower than the same legislation limits.