Pinarosa Avato

The present study aims to highlight the cell protective effect of Tropea red onion (TRO) hydroalcoholic extract and some of its components against “non-essential” heavy metals. For this purpose, the cytoprotective roles of cyanidin, cyanidin-3-O-glucoside and quercetin against Cd, Hg and Pb and of TRO extract against Hg and Pb have been investigated, and data are reported here. To the best of our knowledge, this is the first detailed evaluation of the protective effect against cell damage induced by “non-essential” heavy metals through the simultaneous administration of cyanidin, cyanidin-3-O-glucoside and quercetin with CdCl₂, HgCl₂ or PbCl₂ and the TRO extract against HgCl₂ and PbCl₂. Present data are also compared with our previous results from the TRO extract against Cd. The antioxidant capacity of the extract was also determined by the ferric reducing antioxidant power (FRAP) and the bovine brain peroxidation assay. Both of the assays indicated a good antioxidant capacity of the extract. Cell viability and the impact on necrotic cell death were examined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test and lactate dehydrogenase (LDH) release assay. After 24 h of exposure, Caco-2 cell viability decreased by approximately 50% at 0.25 μM for Cd, Hg and Pb and, after 72 h, the ranking order of “non-essential” heavy metal toxicity on cell viability was PbCl₂ > CdCl₂ > HgCl₂. Cell viability was assessed by treating the cells with the biomolecules at doses of 25, 50 and 100 µg/mL for 24 and 72 h. The same analysis was carried out on Caco-2 cells treated with combinations of TRO extract, cyanidin, cyanidin-3-O-glucoside, or quercetin and “non-essential” heavy metals. Treatments with the bioactive metabolites did not significantly improve cell viability. The identical treatment of Caco-2 cells produced instead LDH release, suggesting a decrease in cell viability. Consistently with the finding that TRO extract showed a good antioxidant activity, we suggest that its higher cytotoxicity, compared to that of the individual assayed phytochemicals, may be derived by the combined antioxidant and chelating properties of all the molecules present in the extract. Therefore, from all the acquired experimental evidence, it appears that the TRO extract may be a better promising protective agent against the toxic effect of Cd, Hg and Pb compared to its bioactive metabolites.

Flavonoids are specialized metabolites produced by plants, as free aglycones or as glycosylated derivatives, which are particularly endowed with a variety of beneficial health properties. The antioxidant, anti-inflammatory, antimicrobial, anticancer, antifungal, antiviral, anti-Alzheimer’s, anti-obesity, antidiabetic, and antihypertensive effects of flavonoids are now known. These bioactive phytochemicals have been shown to act on different molecular targets in cells including the plasma membrane. Due to their polyhydroxylated structure, lipophilicity, and planar conformation, they can either bind at the bilayer interface or interact with the hydrophobic fatty acid tails of the membrane. The interaction of quercetin, cyanidin, and their O-glucosides with planar lipid membranes (PLMs) similar in composition to those of the intestine was monitored using an electrophysiological approach. The obtained results show that the tested flavonoids interact with PLM and form conductive units. The modality of interaction with the lipids of the bilayer and the alteration of the biophysical parameters of PLMs induced by the tested substances provided information on their location in the membrane, helping to elucidate the mechanism of action which underlies some pharmacological properties of flavonoids. To our knowledge, the interaction of quercetin, cyanidin, and their O-glucosides with PLM surrogates of the intestinal membrane has never been previously monitored.

The content of nematicidal metabolites such as saponins, flavonoids and tannins in sulla (Hedysarum coronarium L.) suggests its potential nematicidal activity. In this study, the biocidal activity of 62.5–1000 μg mL⁻¹ concentrations of flavonoid and tannin fractions from sulla was assessed in in vitro assays on the infective juveniles (J2) of the root-knot nematode (RKN) Meloidogyne incognita, while the suppressive effects of soil amendments with 10–40 g kg⁻¹ soil rates of sulla biomass were investigated on potted tomato infested by M. incognita. The content of total nitrogen, carbon, flavonoids, tannins and saponins of sulla experimental material was also determined. After a 96-h exposure, more than 80% of the M. incognita J2 were killed even by a 125 µg mL⁻¹ concentration of the flavonoid extract, while mortality peaked at 89% only at the 1000 µg mL⁻¹ concentration of the tannin solution. Soil incorporation with sulla biomass significantly reduced the M. incognita densities both on tomato roots and in the soil, compared to either the non-treated control and chemical treatment with Fluopyram. The data confirmed the nematicidal potential of sulla, mainly due to its content of flavonoids and tannins, suggesting its suitability as green manure or a soil amendment for sustainable RKN management.

Essential oils (EOs) from lavandin are known for a large spectrum of biological properties but poorly and contrastingly documented for their activity against phytoparasitic nematodes. This study investigated the toxicity of EOs from three different lavandin cultivars, Abrialis, Rinaldi Cerioni, and Sumiens, either to juveniles (J2) and eggs of the root-knot nematode Meloidogyne incognita and to infective stages of the lesion nematode Pratylenchus vulnus. The suppressive activity of treatments with EOs from the three lavandin cultivars in soil infested by M. incognita was also investigated in a greenhouse experiment on potted tomato. The compositional profiles of tested EOs were also analyzed by GC-FID and GC-MS. Linalool was the major component of all the three EOs, as accounting for about 66%, 48%, and 40% of total EO from cv Rinaldi Cerioni, Sumiens, and Abrialis, respectively. Linalool acetate was the second most abundant compound in the EOs from cv Abrialis (18.3%) and Sumiens (14.9%), while significant amounts of camphor (11.5%) and 1,8-cineole (12.1%) were detected in cv Rinaldi Cerioni and Sumiens EOs, respectively. The mortality of M. incognita J2 peaked 82.0%, 95.8%, and 89.8% after a 24 h treatment with 100 mg·mL⁻¹ solutions of cv Abrialis, Rinaldi Cerioni, and Sumiens EOs, respectively. Infective specimens of P. vulnus were largely more sensitive than M. incognita J2, as there were peak mortality rates of 65.5%, 67.7%, and 75.7% after 4 h of exposure to Abrialis, Rinaldi Cerioni, and Sumiens EO, respectively. All three lavandin EOs significantly affected also M. incognita egg hatchability, which reduced to 43.6% after a 48 h egg mass exposure to a 100 µg·mL⁻¹ solution of cv Rinaldi Cerioni EO. Soil treatments with the three lavandin EOs strongly reduced, according to a dose–effect relationship, density of M. incognita eggs, and J2 both on tomato roots and in soil, as well as significantly reduced gall formation on tomato roots. Finally, almost all soil treatments with the lavandin EOs also resulted in a positive impact on tomato plant growth.

Lipids are biomolecules which are present in plants as general metabolites with different functions such as structural, protective and also as storage material. Plants produce a high number of different fatty acids: the most common structural types are long linear hydrocarbon chains, saturated or unsaturated with an even number of carbon atoms. In addition, plants accumulate rare fatty acids with reference to their occurrence and to their structures such as number and arrangement of unsaturated bonds, chain branches, type of functional groups, cyclic structures and halogenation. Their presence is limited in plant leaves, roots or stems, while they are mostly found as components of storage seed oils. The present review aims to describe the structural features of selected unusual rare fatty acids occurring in plants, their bioactivity and applications as pharmaceutical, cosmetic, food and non-food industrial products. Cyanolipids, a group of rare natural lipids containing a cyanogenic group in the molecule and only found in seed oils of a few plant species are also commented.

Sulla (Hedysarum coronarium L.) is a biennal forage legume originated from the Mediterranean basin and used for animal feeding due to its high forage quality and palatability. Several species of Hedysarum have been considered for their nutritional, pharmaceutical, and biological properties, and different applications have been reported, both for human consumption and animal nutrition. Although a systematic investigation of the chemical constituents of Hedysarum spp. has been performed in order to provide chemotaxonomic evidences for the genus and to support the pharmacological application of several species within the genus, few data are available on the chemical constituents of H. coronarium, and only the content of condensed tannins and flavonoids in leaves has been previously reported. In the present paper, results from a detailed chemical analysis of the extracts from the leaves and flowers of H. coronarium grown wild in southern Italy are presented. Identification of the main specialized metabolites within the chemical classes of flavonoids, proanthocyanidins and saponins, is described, including considerations on their content in the two plant organs. Information acquired from this study expands the knowledge on H. coronarium as a source of valuable phytochemicals for different applications in human and animal health and nutrition.

Essential oils (EOs) can be a large source of new food-safe and healthy nematicidal products, due to their strong activity on crop pathogens and pests, including phytoparasitic nematodes, as well as to their low environmental persistence. This review summarizes the results from our 10-year studies on chemical features and nematicidal properties of 16 EOs with different botanical origins and compositions, i.e., the EOs from Artemisia herba-alba Asso (Asteraceae), Cinnamomum camphora (L.) J. Presl. and Cinnamomum verum J. Presl. (Lauraceae), Citrus aurantium L., Cinnamomum. sinensis L. Osbeck and Ruta graveolens L. (Rutaceae), Eucalyptus citriodora Hook, Eucalyptus globulus Labill. and Syzygium aromaticum (L.) Marry et Perry (Myrtaceae), Mentha piperita L., Monarda didyma L., Monarda. fistulosa L., Rosmarinus officinalis L. and Thymus satureioides Cosson (Lamiaceae), Pelargonium asperum Ehrh ex Willd (Geraniaceae) and Schinus molle L. (Anacardiaceae). All these EOs were chemically characterized and tested in vitro and/or in vivo for their activity against the phytoparasitic species Meloidogyne incognita Kofoid et White (Chitw.), Pratylenchus vulnus Allen et Jensen and Xiphinema index Thorne et Allen. Toxicity bioassays were conducted by exposing 2nd stage juveniles (J2) of M. incognita, mixed-age specimens of P. vulnus and adult females of X. index to 2–100 μg mL⁻¹ concentrations of EOs or EO’s major constituents for 4–96 h and checking mortality effect after a further 24–72 h permanence in water. Egg hatchability bioassays consisted in exposing (24–48 h) M. incognita egg masses to 500–1000 mg mL⁻¹ EO solutions followed by a 5-week hatching test in water. The in vivo experiments were undertaken in sandy soil strongly infested by M. incognita and treated with different doses of EOs, applied either in water solution or by fumigation. The effects of the treatments on nematode infestation on tomato and in soil were checked at the end of each experiment. Structure-activity relationships, as suggested by the different chemical compositions of tested EOs, were also highlighted. In agreement with literature data, our studies indicated that most of the tested EOs are highly suitable for the formulation of new safe nematicides, though still retarded by the lack of efficient stabilization processes and standardized EOs’ components and extraction techniques.