Use of Biostimulants as a New Approach for the Improvement of Phytoremediation Performance-A Review.

Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. Bioremediation techniques, on the other hand, represent a promising alternative. Among them, phytoremediation is attracting particular attention, a green methodology that relies on the use of plant species to remediate contaminated sites or prevent the dispersion of xenobiotics into the environment. In this review, after a brief introduction focused on pollution and phytoremediation, the use of plant biostimulants (PBs) in the improvement of the remediation effectiveness is proposed. PBs are substances widely used in agriculture to raise crop production and resistance to various types of stress. Recent studies have also documented their ability to counteract the deleterious effects of pollutants on plants, thus increasing the phytoremediation efficiency of some species. The works published to date, reviewed and discussed in the present work, reveal promising prospects in the remediation of polluted environments, especially for heavy metals, when PBs derived from humic substances, protein and amino acid hydrolysate, inorganic salts, microbes, seaweed, plant extracts, and fungi are employed.

Anthocyanic pigments from elicited in vitro grown shoot cultures of Vaccinium corymbosum L., cv. Brigitta Blue, as photosensitizer in natural dye-sensitized solar cells (NDSSC).

We investigated the effect on anthocyanins and total phenols content and antioxidant capacity of in vitro shoot cultures of Vaccinium corymbosum L., cv. Brigitta Blue, grown on an eliciting medium supplied with 10 µM naphthalene acetic acid, in combination with reduced content of salts and organics in respect to the basal medium. After 45 days, higher content of total phenols and anthocyanins was obtained from extracts of shoots grown on the elicitation medium. Anthocyanin molecules, absent in control shoots, were identified by HPLC-MS as delphinidine-glycoside, cyanidine-glycoside, delphinidine-arabinoside, cyanidine- arabinoside and cyanidine-acetylglycoside. Chlorogenic acid, present in control shoots, was nearly absent in elicited shoots. We exploited the anthocyanin - based raw extracts of "Brigitta Blue" shoots grown on the elicitation medium as a source of natural dye photosensitizers for Dye Sensitized Solar Cells, taking into account that such raw extracts showed antioxidant properties and photostability features. A purified dye was also prepared and the comparison of the latter with the raw one has been analysed by spectrophotometric, chromatographic and power conversion efficiency determination. The power conversion efficiencies from the raw and the purified dye were not different and they were comparable to the data obtained by other authors with anthocyanin-based dyes from in vivo grown plants.

Antineoplastic activity of strawberry (Fragaria×ananassa Duch.) crude extracts on B16-F10 melanoma cells.

The antiproliferative and differentiation potential of anthocyanin-rich strawberry fruit crude extracts (SE) were investigated on B16-F10 murine melanoma cells. Treatment of melanoma cells with SE produced a remarkable reduction of cell proliferation, paralleled with both the lowering of the intracellular levels of polyamine, and the enhancement of tissue transglutaminase (TG2, EC 2.3.2.13) activity (used as a differentiation marker). To gain further insight into profiling altered protein expression as a potential biomarker of the SE action on melanoma cells, analysis of the proteomic profile was performed on the treated B16-F10 cells, compared to the control. Following SE treatment, 30 proteins resulted up-regulated, and 87 proteins were down-regulated. In particular proteins overexpressed in cancer cells, involved in tumor progression and metabolism, were down-regulated. The possibility that SE may affect the Warburg effect in B16-F10 melanoma cells is discussed.