Impact of Hydrophobic Chains in Five-Coordinate Glucoconjugate Pt(II) Anticancer Agents

This study describes new platinum(II) cationic five-coordinate complexes (1-R,R’) of the formula [PtR(NHC)(dmphen)(ethene)]CF3SO3 (dmphen = 2,9-dimethyl-1,10-phenanthroline), containing in their axial positions an alkyl group R (methyl or octyl) and an imidazole-based NHC-carbene ligand with a substituent R’ of variable length (methyl or octyl) on one nitrogen atom. The Pt–carbene bond is stable both in DMSO and in aqueous solvents. In DMSO, a gradual substitution of dmphen and ethene is observed, with the formation of a square planar solvated species. Octanol/water partitioning studies have revealed the order of hydrophobicity of the complexes (1-Oct,Me > 1-Oct,Oct > 1-Me,Oct > 1-Me,Me). Their biological activity was investigated against two pairs of cancer and non-cancer cell lines. The tested drugs were internalized in cancer cells and able to activate the apoptotic pathway. The reactivity of 1-Me,Me with DNA and protein model systems was also studied using UV–vis absorption spectroscopy, fluorescence, and X-ray crystallography. The compound binds DNA and interacts in various ways with the model protein lysozyme. Remarkably, structural data revealed that the complex can bind lysozyme via non-covalent interactions, retaining its five-coordinate geometry

Productivity and biochemical composition of Tetradesmus obliquus and Phaeodactylum tricornutum: effects of different cultivation approaches

The present work evaluated biomass productivity, carbon dioxide fixation rate, and biochemical composition of two microalgal species, Phaeodactylum tricornutum (Bacillariophyta) and Tetradesmus obliquus (Chlorophyta), cultivated indoors in high-technology photobioreactors (HT-PBR) and outdoors both in pilot ponds and low-technology photobioreactors in a greenhouse in southern Italy. Microalgae were grown in standard media, under nitrogen starvation, and in two liquid digestates obtained from anaerobic digestion of agro-zootechnical and vegetable biomass. P. tricornutum, cultivated in semi-continuous mode in indoor HT-PBRs with standard medium, showed a biomass productivity of 21.0 ± 2.3 g mâ2 dâ1. Applying nitrogen starvation, the lipid productivity increased from 2.3 up to 4.5 ± 0.5 g mâ2 dâ1, with a 24 % decrease of biomass productivity. For T. obliquus, a biomass productivity of 9.1 ± 0.9 g mâ2 dâ1 in indoor HT-PBR was obtained using standard medium. Applying liquid digestates as fertilizers in open ponds, T. obliquus gave a biomass productivity (10.8 ± 2.0 g mâ2 dâ1) not statistically different from complete medium such as P. tricornutum (6.5 ± 2.2 g mâ2 dâ1). The biochemical data showed that the fatty acid composition of the microalgal biomass was affected by the different cultivation conditions for both microalgae. In conclusion, it was found that the microalgal productivity in standard medium was about doubled in HT-PBR compared to open ponds for P. tricornutum and was about 20 % higher for T. obliquus

Evaluation of anaerobic digestates from different feedstocks as growth media for Tetradesmus obliquus, Botryococcus braunii, Phaeodactylum tricornutum and Arthrospira maxima

In this paper, two freshwater microalgae (Tetradesmus obliquus and Botryococcus braunii), a marine diatom (Phaeodactylum tricornutum) and a photosynthetic cyanobacterium (Arthrospira maxima) were investigated for their ability to grow on liquid digestates (LDs). Three LDs were obtained from anaerobic digestion of different organic wastes: zootechnical (ZW LD), vegetable biomass (VW LD) and the organic fraction of municipal solid wastes (MW LD). All the strains showed the same growth performance on VW LD as on the respective standard media (SM), while ZW LD was efficient only for growth of T. obliquus and B. braunii. MW LD was the poorest growth medium for all the strains. Data on nutrient removal efficiency showed that A. maxima and T. obliquus made the best use of NH4+-N with removal values ranging between 98.9–99.8%, while P. tricornutum and B. braunii showed values of 79.0 and 88.5% respectively. Applying repeated batch cultivation in photobioreactors, the biochemical composition of A. maxima and T. obliquus biomass grown on ZW LD and VW LD, showed an increase of lipid, carbohydrates and ash in both microalgae. Biomass biochemical profiles suggest possible applications in feed, chemicals and energy sectors

Biochemical composition and in vitro digestibility of Galdieria sulphuraria grown on spent cherry-brine liquid

The aim of this work was to valorise an industrial food by-product and to produce a microalgal biomass rich in phytochemicals at high added value for food and nutraceutical applications. The biochemical composition, in vitro digestibility and antioxidant activity of Galdieria sulphuraria biomass grown heterotrophically on standard medium (SM) and on spent Cherry-Brine Liquid (sCBL) were assessed and compared. The biomass produced in sCBL was characterized by a lower content of proteins and lipids, while showing an increase in carbohydrates and polyphenols (5.3 vs 1.6 mg g−1). The sCBL biomass lipid moiety had a lower palmitic and linoleic acid content and a higher oleic acid concentration than SM. The total protein digestibility of Galdieria grown in SM and sCBL was 79% and 63% respectively. The antioxidant activity (AA) of G. sulphuraria biomass grown in sCBL was significantly higher than that grown in SM. Studying the AA release for sCBL biomass during the digestion, the highest value was found in the intestinal phase. In conclusion, G. sulphuraria has a valuable nutritional profile and could become a valuable source of phytochemicals, depending on the cultivation media. Cultivation on sCBL would allow an environmentally and economically sustainable process, valorising the food by-product and producing a microalgal biomass rich in cherry anthocyanins with high AA released at the intestinal level.</p