Unveiling the potential of Pseudococcomyxa simplex: a stepwise extraction for cosmetic applications.

Microalgae are gaining attention as they are considered green fabrics able to synthesize many bioactive metabolites, with unique biological activities. However, their use at an industrial scale is still a challenge because of the high costs related to upstream and downstream processes. Here, a biorefinery approach was proposed, starting from the biomass of the green microalga Pseudococcomyxa simplex for the extraction of two classes of molecules with a potential use in the cosmetic industry. Carotenoids were extracted first by an ultrasound-assisted extraction, and then, from the residual biomass, lipids were obtained by a conventional extraction. The chemical characterization of the ethanol extract indicated lutein, a biosynthetic derivative of α-carotene, as the most abundant carotenoid. The extract was found to be fully biocompatible on a cell-based model, active as antioxidant and with an in vitro anti-aging property. In particular, the lutein-enriched fraction was able to activate Nrf2 pathway, which plays a key role also in aging process. Finally, lipids were isolated from the residual biomass and the isolated fatty acids fraction was composed by palmitic and stearic acids. These molecules, fully biocompatible, can find application as emulsifiers and softener agents in cosmetic formulations. Thus, an untapped microalgal species can represent a sustainable source for cosmeceutical formulations. KEY POINTS: • Pseudococcomyxa simplex has been explored in a cascade approach. • Lutein is the main extracted carotenoid and has antioxidant and anti-aging activity. • Fatty acids are mainly composed of palmitic and stearic acids.

The Undeniable Potential of Thermophiles in Industrial Processes.

Extremophilic microorganisms play a key role in understanding how life on Earth originated and evolved over centuries. Their ability to thrive in harsh environments relies on a plethora of mechanisms developed to survive at extreme temperatures, pressures, salinity, and pH values. From a biotechnological point of view, thermophiles are considered a robust tool for synthetic biology as well as a reliable starting material for the development of sustainable bioprocesses. This review discusses the current progress in the biomanufacturing of high-added bioproducts from thermophilic microorganisms and their industrial applications.

Microalgae Flocculation: Assessment of Extraction Yields and Biological Activity.

Downstream costs represent one of the main obstacles to enabling microalgae to become widespread. The development of an economical, easily scaled-up strategy could reduce the overall process costs. Here, different flocculants were tested on different microalgae strains and a cyanobacterium. The results indicate that flocculation could be an alternative to centrifugation, as CaCl2 induced a complete flocculation of green and red marine strains (96 ± 4% and 87.0 ± 0.5%, respectively), whereas Chitosan was the only agent able to induce flocculation on the cyanobacterium (46 ± 1%). As for the thermoacidophilic red microalga, 100% flocculation was achieved only by increasing the pH. Carotenoids were extracted from the flocculated biomass, and the strategy improved with the use of the wet biomass. The results indicate that flocculation does not affect carotenoid yield, which is at least the same than that obtained upon centrifugation and extraction from the wet biomass. Then, for the first time, the biological activity of the extracts obtained from the flocculated biomasses was evaluated. The results indicate that only the green microalga extract shows increased antioxidant activity. In conclusion, this work highlights that a general downstream procedure cannot be developed for microalgae strains but should be rationally tailored.

Pentadecanoic Acid-Releasing PDMS: Towards a New Material to Prevent S. epidermidis Biofilm Formation.

Microbial biofilm formation on medical devices paves the way for device-associated infections. Staphylococcus epidermidis is one of the most common strains involved in such infections as it is able to colonize numerous devices, such as intravenous catheters, prosthetic joints, and heart valves. We previously reported the antibiofilm activity against S. epidermidis of pentadecanoic acid (PDA) deposited by drop-casting on the silicon-based polymer poly(dimethyl)siloxane (PDMS). This material exerted an antibiofilm activity by releasing PDA; however, a toxic effect on bacterial cells was observed, which could potentially favor the emergence of resistant strains. To develop a PDA-functionalized material for medical use and overcome the problem of toxicity, we produced PDA-doped PDMS by either spray-coating or PDA incorporation during PDMS polymerization. Furthermore, we created a strategy to assess the kinetics of PDA release using ADIFAB, a very sensitive free fatty acids fluorescent probe. Spray-coating resulted in the most promising strategy as the concentration of released PDA was in the range 0.8-1.5 µM over 21 days, ensuring long-term effectiveness of the antibiofilm molecule. Moreover, the new coated material resulted biocompatible when tested on immortalized human keratinocytes. Our results indicate that PDA spray-coated PDMS is a promising material for the production of medical devices endowed with antibiofilm activity.

Elicitor-mediated simultaneous accumulation of phloridzin and ursolic acid in Annurca apple peel-derived calli.

BACKGROUND: Apple peel is rich in natural molecules, many exhibiting a significant bioactivity. In this study, our objective was to establish a novel callus line derived from the apple peel of the Italian local variety Annurca, known to accumulate high levels of dihydrochalcones and terpenes. In this regard, we tested the impact of one elicitor, yeast extract, on the expression of genes encoding key enzymes involved in phloridzin and ursolic acid biosynthesis, leading to the accumulation of these antioxidant compounds. We also assessed the bioactivity of callus extracts enriched in these phytochemicals. RESULTS: After the elicitation, data showed increased expression of genes directly related to the synthesis of phloridzin and ursolic acid that were found to accumulate within the cultures. This presumably could explain the remarkable activity of extracts from the elicited-calli in inhibiting the growth of Staphylococcus aureus and Bacillus cereus. Also, the extracts enriched in antioxidant compounds inhibited reactive oxygen species (ROS) production in human cells exposed to ultraviolet-A (UV-A) radiation. CONCLUSION: Our results underscore the vast potential of the Annurca apple peel cell line in producing natural compounds that can be employed as food components to promote human health. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Aqueous Extracts from Hemp Seeds as a New Weapon against Staphylococcus epidermidis Biofilms.

This study investigated the antibiofilm activity of water-soluble extracts obtained under different pH conditions from Cannabis sativa seeds and from previously defatted seeds. The chemical composition of the extracts, determined through GC-MS and NMR, revealed complex mixtures of fatty acids, monosaccharides, amino acids and glycerol in ratios depending on extraction pH. In particular, the extract obtained at pH 7 from defatted seeds (Ex7d) contained a larger variety of sugars compared to the others. Saturated and unsaturated fatty acids were found in all of the analysed extracts, but linoleic acid (C18:2) was detected only in the extracts obtained at pH 7 and pH 10. The extracts did not show cytotoxicity to HaCaT cells and significantly inhibited the formation of Staphylococcus epidermidis biofilms. The exception was the extract obtained at pH 10, which appeared to be less active. Ex7d showed the highest antibiofilm activity, i.e., around 90%. Ex7d was further fractionated by HPLC, and the antibiofilm activity of all fractions was evaluated. The 2D-NMR analysis highlighted that the most active fraction was largely composed of glycerolipids. This evidence suggested that these molecules are probably responsible for the observed antibiofilm effect but does not exclude a possible synergistic contribution by the other components.

An Alternative Exploitation of Synechocystis sp. PCC6803: A Cascade Approach for the Recovery of High Added-Value Products.

Microalgal biomass represents a very interesting biological feedstock to be converted into several high-value products in a biorefinery approach. In this study, the cyanobacterium Synechocystis sp. PCC6803 was used to obtain different classes of molecules: proteins, carotenoids and lipids by using a cascade approach. In particular, the protein extract showed a selective cytotoxicity towards cancer cells, whereas carotenoids were found to be active as antioxidants both in vitro and on a cell-based model. Finally, for the first time, lipids were recovered from Synechocystis biomass as the last class of molecules and were successfully used as an alternative substrate for the production of polyhydroxyalkanoate (PHA) by the native PHA producer Pseudomonas resinovorans. Taken together, our results lead to a significant increase in the valorization of Synechocystis sp. PCC6803 biomass, thus allowing a possible offsetting of the process costs.

Evaluation of Auranofin Loading within Ferritin Nanocages.

Auranofin (AF), a gold(I) compound that is currently used for the treatment of rheumatoid arthritis and is in clinical trials for its promising anticancer activity, was encapsulated within the human H-chain and the horse spleen ferritin nanocages using the alkaline disassembly/reassembly protocol. The aim of the work was to highlight possible differences in their drug loading capacity and efficacy. The drug-loaded ferritins were characterized via UV-vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy to assess AF encapsulation and to define the exact amount of gold atoms trapped in the Ft cavity. The crystal structures allowed us to define the nature of AF interaction with both ferritins and to identify the gold binding sites. Moreover, the biological characterization let us to obtain preliminary information on the cytotoxic effect of AF when bound to the human H-chain.

Autophagy Alteration in ApoA-I Related Systemic Amyloidosis.

Amyloidoses are characterized by the accumulation and aggregation of misfolded proteins into fibrils in different organs, leading to cell death and consequent organ dysfunction. The specific substitution of Leu 75 for Pro in Apolipoprotein A-I protein sequence (ApoA-I; L75P-ApoA-I) results in late onset amyloidosis, where deposition of extracellular protein aggregates damages the normal functions of the liver. In this work, we describe that the autophagic process is inhibited in the presence of the L75P-ApoA-I amyloidogenic variant in stably transfected human hepatocyte carcinoma cells. The L75P-ApoA-I amyloidogenic variant alters the redox status of the cells, resulting into excessive mitochondrial stress and consequent cell death. Moreover, L75P-ApoA-I induces an impairment of the autophagic flux. Pharmacological induction of autophagy or transfection-enforced overexpression of the pro-autophagic transcription factor EB (TFEB) restores proficient proteostasis and reduces oxidative stress in these experimental settings, suggesting that pharmacological stimulation of autophagy could be a promising target to alleviate ApoA-I amyloidosis.

Arsenoplatin-Ferritin Nanocage: Structure and Cytotoxicity.

Arsenoplatin-1 (AP-1), the prototype of a novel class of metallodrugs containing a PtAs(OH)2 core, was encapsulated within the apoferritin (AFt) nanocage. UV-Vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy measurements confirmed metallodrug encapsulation and allowed us to determine the average amount of AP-1 trapped inside the cage. The X-ray structure of AP-1-encapsulated AFt was solved at 1.50 Å. Diffraction data revealed that an AP-1 fragment coordinates the side chain of a His residue. The biological activity of AP-1-loaded AFt was comparatively tested on a few representative cancer and non-cancer cell lines. Even though the presence of the cage reduces the overall cytotoxicity of AP-1, it improves its selectivity towards cancer cells.

Thermo resistant antioxidants from photoautotrophic microorganisms: screening and characterization.

The demand for natural antioxidants to be used in food industry is increasing, as synthetic antioxidants are toxic and have high production costs. Specifically, food processing and preservation require antioxidants resistant to thermal sterilization processes. In this study, twenty-five strains among microalgae and cyanobacteria were screened as antioxidants producers. The species Enallax sp., Synechococcus bigranulatus and Galdieria sulphuraria showed the highest content of chlorophyll a and total carotenoids. In vitro stability and antioxidant activity of the ethanolic extracts were performed. The results revealed that pigments present in the extracts, obtained from the previously mentioned species, were stable at room temperature and exhibited in vitro free radical scavenging potential with IC50 values of 0.099 ± 0.001, 0.048 ± 0.001 and 0.13 ± 0.02 mg mL-1, respectively. Biocompatibility assay showed that the extracts were not toxic on immortalized cell lines. The antioxidant activity was also tested on a cell-based model by measuring intracellular ROS levels after sodium arsenite treatment. Noteworthy, extracts were able to exert the same protective effect, before and after the pasteurization process. Results clearly indicate the feasibility of obtaining biologically active and thermostable antioxidants from microalgae. Green solvents can be used to obtain thermo-resistant antioxidants from cyanobacteria and microalgae which can be used in the food industry. Thus, the substitution of synthetic pigments with natural ones is now practicable.

Pt(II) versus Pt(IV) in Carbene Glycoconjugate Antitumor Agents: Minimal Structural Variations and Great Performance Changes.

Octahedral Pt(IV) complexes (2Pt-R) containing a glycoconjugate carbene ligand were prepared and fully characterized. These complexes are structural analogues to the trigonal bipyramidal Pt(II) species (1Pt-R) recently described. Thus, an unprecedented direct comparison between the biological properties of Pt compounds with different oxidation states and almost indistinguishable structural features was performed. The stability profile of the novel Pt(IV) compounds in reference solvents was determined and compared to that of the analogous Pt(II) complexes. The uptake and antiproliferative activities of 2Pt-R and 1Pt-R were evaluated on the same panel of cell lines. DNA and protein binding properties were assessed using human serum albumin, the model protein hen egg white lysozyme, and double stranded DNA model systems by a variety of experimental techniques, including UV-vis absorption spectroscopy, fluorescence, circular dichroism, and electrospray ionization mass spectrometry. Although the compounds present similar structures, their in-solution stability, cellular uptake, and DNA binding properties are diverse. These differences may represent the basis of their different cytotoxicity and biological activity.

Towards green extraction methods from microalgae learning from the classics.

Microalgae started receiving attention as producers of third generation of biofuel, but they are rich in many bioactive compounds. Indeed, they produce many molecules endowed with benefic effects on human health which are highly requested in the market. Thus, it would be important to fractionate algal biomass into its several high-value compounds: this represents the basis of the microalgal biorefinery approach. Usually, conventional extraction methods have been used to extract a single class of molecules, with many side effects on the environment and on human health. The development of a green downstream platform could help in obtaining different class of molecules with high purity along with low environmental impact. This review is focused on technical advances that have been performed, from classic methods to the newest and green ones. Indeed, it is fundamental to set up new procedures that do not affect the biological activity of the extracted molecules. A comparative analysis has been performed among the conventional methods and the new extraction techniques, i.e., switchable solvents and microwave-assisted and compressed fluid extractions.

A cascade extraction of active phycocyanin and fatty acids from Galdieria phlegrea.

The setup of an economic and sustainable method to increase the production and commercialization of products from microalgae, beyond niche markets, is a challenge. Here, a cascade approach has been designed to optimize the recovery of high valuable bioproducts starting from the wet biomass of Galdieria phlegrea. This unicellular thermo-acidophilic red alga can accumulate high-value compounds and can live under conditions considered hostile to most other species. Extractions were performed in two sequential steps: a conventional high-pressure procedure to recover phycocyanins and a solvent extraction to obtain fatty acids. Phycocyanins were purified to the highest purification grade reported so far and were active as antioxidants on a cell-based model. Fatty acids isolated from the residual biomass contained high amount of PUFAs, more than those recovered from the raw biomass. Thus, a simple, economic, and high effective procedure was set up to isolate phycocyanin at high purity levels and PUFAs.

Isolation of Myricitrin and 3,5-di-O-Methyl Gossypetin from Syzygium samarangense and Evaluation of their Involvement in Protecting Keratinocytes against Oxidative Stress via Activation of the Nrf-2 Pathway.

The wax apple (Syzygium samarangense) is traditionally employed as an antibacterial and immunostimulant drug in traditional medicine. This plant is rich in different flavonoids and tannins. In this study, we isolated two compounds from S. samarangense leaves: myricitrin and 3,5-di-O-methyl gossypetin. Then, we investigated the mechanisms of action of the two compounds against oxidative stress (induced by sodium arsenite) and inflammation (induced by UV light) on human keratinocytes. We could clearly demonstrate that the pre-treatment of cells with both compounds was able to mitigate the negative effects induced by oxidative stress, as no alteration in reactive oxygen species (ROS) production, glutathione (GSH) level, or protein oxidation was observed. Additionally, both compounds were able to modulate mitogen-activated protein kinase (MAPK) signaling pathways to counteract oxidative stress activation. Finally, we showed that 3,5-di-O-methyl gossypetin exerted its antioxidant activity through the nuclear transcription factor-2 (Nrf-2) pathway, stimulating the expression of antioxidant proteins, such as HO-1 and Mn-SOD-3.

Pentadecanal inspired molecules as new anti-biofilm agents against Staphylococcus epidermidis.

Staphylococcus epidermidis, a harmless human skin colonizer, is a significant nosocomial pathogen in predisposed hosts because of its capability to form a biofilm on indwelling medical devices. In a recent paper, the purification and identification of the pentadecanal produced by the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, able to impair S. epidermidis biofilm formation, were reported. Here the authors report on the chemical synthesis of pentadecanal derivatives, their anti-biofilm activity on S. epidermidis, and their action in combination with antibiotics. The results clearly indicate that the pentadecanal derivatives were able to prevent, to a different extent, biofilm formation and that pentadecanoic acid positively modulated the antimicrobial activity of the vancomycin. The cytotoxicity of these new anti-biofilm molecules was tested on two different immortalized eukaryotic cell lines in view of their potential applications.

Protective effect of Opuntia ficus-indica L. cladodes against UVA-induced oxidative stress in normal human keratinocytes.

Opuntia ficus-indica L. is known for its beneficial effects on human health, but still little is known on cladodes as a potent source of antioxidants. Here, a direct, economic and safe method was set up to obtain water extracts from Opuntia ficus-indica cladodes rich in antioxidant compounds. When human keratinocytes were pre-treated with the extract before being exposed to UVA radiations, a clear protective effect against UVA-induced stress was evidenced, as indicated by the inhibition of stress-induced processes, such as free radicals production, lipid peroxidation and GSH depletion. Moreover, a clear protective effect against apoptosis in pre-treated irradiated cells was evidenced. We found that eucomic and piscidic acids were responsible for the anti-oxidative stress action of cladode extract. In conclusion, a bioactive, safe, low-cost and high value-added extract from Opuntia cladodes was obtained to be used for skin health/protection.

Profiling of Petroselinum sativum (mill.) fuss phytoconstituents and assessment of their biocompatibility, antioxidant, anti-aging, wound healing, and antibacterial activities.

Petroselinum sativum, known as parsley, is a fragrant herb that possesses a rich heritage of utilization in traditional medicinal practices. In this study, we annotated the phytocontents of the aqueous and ethanolic extracts of P. sativum and investigated their antioxidant, cytoprotective, antiaging, wound healing, and antibacterial activities. LC-MS/MS analysis of both extracts revealed the presence of 47 compounds belonging to diverse groups including organic acids, phenolic acids, and flavonoids. By MTT assay, the extracts were fully biocompatible on immortalized human keratinocytes (HaCaT) while they inhibited intracellular ROS formation (DCFDA assay) and prevented GSH depletion (DTNB assay) upon UVA exposure. In addition, the extracts were potent in inhibiting the in vitro activities of skin-related enzymes mainly elastase, tyrosinase, collagenase and hyaluronidase. Using the scratch assay, P. sativum aqueous extract significantly enhanced wound closure when compared to untreated HaCaT cells. Moreover, both extracts inhibited Pseudomonas aeruginosa's growth, reduced biofilm formation, and impaired the swimming and swarming motilities. Also, the aqueous extract was able to inhibit the production of bacterial pigments on plates. These findings strongly suggest the usefulness of P. sativum as a source of phytochemicals suitable for dermo-cosmeceutical applications.

Shedding Light on the Hidden Benefit of Porphyridium cruentum Culture.

Microalgae can represent a reliable source of natural compounds with different activities. Here, we evaluated the antioxidant and anti-inflammatory activity of sulfated exopolysaccharides (s-EPSs) and phycoerythrin (PE), two molecules naturally produced by the red marine microalga Porphyridium cruentum (CCALA415). In vitro and cell-based assays were performed to assess the biological activities of these compounds. The s-EPSs, owing to the presence of sulfate groups, showed biocompatibility on immortalized eukaryotic cell lines and a high antioxidant activity on cell-based systems. PE showed powerful antioxidant activity both in vitro and on cell-based systems, but purification is mandatory for its safe use. Finally, both molecules showed anti-inflammatory activity comparable to that of ibuprofen and helped tissue regeneration. Thus, the isolated molecules from microalgae represent an excellent source of antioxidants to be used in different fields.