Angelina Izzo

Phytotoxicity evaluation of five pharmaceutical pollutants detected in surface water on germination and growth of cultivated and spontaneous plants.

The phytotoxicity of 5 pharmaceuticals detected in Italian rivers, atorvastatin (7-[2-(4-fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-propan-2-yl-pyrrol-1-yl]-3,5-dihydroxy-heptanoic acid), gemfibrozil (5-(2,5-dimethylphenoxy)-2,2-dimethyl-pentanoic acid), tamoxifene (2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-N,N-dimethyl-ethanamine), ethinyl estradiol (17-ethynyl-13-methyl-7,8,9,11, 12,13,14,15,16,17-decahydro-6H-cyclopenta[a]phenanthrene-3,17-diol) and sildenafil (methyl-9-propyl-2,4,7,8-tetrazabicyclo[4.3.0] nona-3,8,10-trien-5-one), has been assessed in a laboratory model. The treatment system consists of three main successive sections. The first one includes the phytotoxic evaluation of the single compounds on crops, Lactuca sativa (lettuce), Dacus carota subsp. sativa (carrot), and Lycopersicon esculentum (tomato), until the 10−9 M, concentration lower then the environmental amounts. The second section includes the phytotoxicity assessment of all the selected chemicals on wild species, Avena fatua (wild oats), Amaranthus retroflexus (redroot pigweed), Lolium perenne (perennial ryegrass), Taraxacum officinale (common dandelion), and Chenopodium album (lambsquarter), at the same concentration as previously used. The third section of the procedure includes the evaluation of the effects of the five pharmaceuticals, at 1 μM and 1 nM environmental concentrations, on the metabolism of L. sativa. The variation of the composition of the photosynthetic pigments, sugars, lipids, phenols, fatty acids and flavonoids in lettuce seedlings exposed to the pollutants in respect to the blank was evaluated. The results of the phytotoxicity assays showed the possibility of a notable impact on the different vegetal communities and evidenced different sensitivity among cultivated and wild species, probably due to the different plant physiology.

Potential allelopathic interference of Melilotus neapolitana metabolites on three coexisting species of Mediterranean herbaceous plant community

Abstract This study is focused on the allelopathic interference of Melilotus neapolitana, an annual stenomediterranean species frequently occurring in the herbaceous plant community of the Mediterranean macchia, on three coexisting species of the Mediterranean herbaceous plant community. The ethereal and methanol extracts of the plant led to the isolation of 11 allelochemicals: coumarin, cis- and trans-melilotoside, the dihydromelilotoside, seven flavone glycosides, as well as the inactive β-sitosterol, a C13-norterpene glucoside and a polyphenol. All the structures have been elucidated on the basis of their spectroscopic features. The organic extracts and all the pure compounds have been assayed for their allelopathic activity on three coexisting species, Petrorhagia velutina, Dactylis hispanica, and Phleum subulatum. The cluster analysis has shown a clear structure-activity relationship, by evidencing four main groups of compounds with a specific effect patterns. Coumarin, the most abundant compound both in the plant extracts and soil, is found to be highly phytotoxic on all the tested species. As for the flavone glycosides, it is shown that aglycones play an important role due to their bioactivity.

Kaempferol glycosides from Lobularia maritima and their potential role in plant interactions.

Six kaempferol glycosides, four of them characterized for the first time, were isolated from the leaf extract of Lobularia maritima. The structural elucidation was performed by a combined approach using Electrospray-Ionization Triple-Quadrupole Mass-Spectrometric (ESI/TQ/MS) techniques, and 1D- and 2D-NMR experiments (1H, 13C, DEPT, DQ-COSY, TOCSY, ROESY, NOESY, HSQC, HMBC, and HSQC-TOCSY). The isolated kaempferol derivatives have different disaccharide substituents at C(3) and four of them have a rhamnose unit at C(7). To evaluate their potential allelopathic role within the herbaceous plant community, the compounds, as well as the aglycone obtained from enzymatic hydrolysis, have been tested in vitro on three coexisting plant species, Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum. The results obtained allow us to hypothesize that the type of the sugar modulates the biological response. The bioassay data, analyzed by a multivariate approach, and grouping the compounds on the basis of the number of sugar units and the nature of carbohydrates present in the disaccharide moiety, indicate a structure-activity relationship.