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The microalga Raphidocelis subcapitata was isolated from the Nitelva River (Norway) and subsequently deposited in the collection of the Norwegian Institute of Water Research as “ Selenastrum capricornutum Printz”. This freshwater microalga, also known as Pseudokirchneriella subcapitata , acquired much of its notoriety due to its high sensitivity to different chemical species, which makes it recommended by different international organizations for the assessment of ecotoxicity. However, outside this scope, R. subcapitata continues to be little explored. This review aims to shed light on a microalga that, despite its popularity, continues to be an “illustrious” unknown in many ways. Therefore, R. subcapitata taxonomy, phylogeny, shape, size/biovolume, cell ultra-structure, and reproduction are reviewed. The nutritional and cultural conditions, chronological aging, and maintenance and preservation of the alga are summarized and critically discussed. Applications of R. subcapitata , such as its use in aquatic toxicology (ecotoxicity assessment and elucidation of adverse toxic outcome pathways) are presented. Furthermore, the latest advances in the use of this alga in biotechnology, namely in the bioremediation of effluents and the production of value-added biomolecules and biofuels, are highlighted. To end, a perspective regarding the future exploitation of R. subcapitata potentialities, in a modern concept of biorefinery, is outlined. Graphical Abstract Key points • An overview of alga phylogeny and physiology is critically reviewed. • Advances in alga nutrition, cultural conditions, and chronological aging are presented. • Its use in aquatic toxicology and biotechnology is highlighted.

Aromatic plants are rich sources of bioactive compounds with recognized therapeutic potential. This study investigated the phytochemical composition and biological activities of ethanolic extracts from four aromatic species—Thymus vulgaris L. (thyme), Rosmarinus officinalis L. (rosemary), Aloysia citrodora (lemon verbena), and Tanacetum balsamita L. (costmary)—using HeLa human cancer cells as a model. LC–MS analysis identified 28–44 metabolites per species, with phenolic compounds and terpenoids comprising 58–67% of total metabolites. Biological assays demonstrated concentration-dependent inhibition of HeLa cell metabolism down to 150 µg/mL, with rosemary displaying the strongest effects. LDH assays confirmed membrane disruption, most notably for lemon verbena (ca. 80% of release), and cellular proliferation was significantly disrupted by all extracts, most notably for thyme (70% reduction). Under oxidative conditions, costmary, thyme, and lemon verbena reduced intracellular ROS by up to 35% and all extracts suppressed IL-6 secretion, with rosemary showing the strongest anti-inflammatory response, lowering IL-6 levels to near or below the assay’s detection limit. Out of all the extracts, rosemary exhibited the most pronounced effects across cytotoxic, antioxidant, and cytokine assays, suggesting synergistic activity of its phenolic and terpenoid constituents. Multivariate analyses (correlation and PCA) linked specific metabolite classes to bioactivity patterns, providing insight into the mechanistic diversity underlying plant-specific effects. Overall, the results support the potential of these aromatic plants as sources of multifunctional bioactive compounds with anticancer and anti-inflammatory properties.

The green alga Pseudokirchneriella subcapitata is widely used in ecotoxicity assays and has great biotechnological potential as feedstock. This work aims to characterize the physiology of this alga associated with the aging resulting from the incubation of cells for 21 days, in the OECD medium, with continuous agitation and light exposure, in a batch mode. After inoculation, cells grow exponentially during 3 days, and the culture presents a typical green color. In this phase, “young” algal cells present, predominantly, a lunate morphology with the chloroplast occupying a large part of the cell, maximum photosynthetic activity and pigments concentration, and produce starch as a reserve material. Between the 5 th and the 12 th days of incubation, cells are in the stationary phase. The culture becomes less green, and the cells stop dividing (≥ 99% have one nucleus) and start to age. “Old” algal cells present chloroplast shrinkage, an abrupt decline of chlorophylls content, and photosynthetic capacity ( Fv/Fm and ɸ PSII ), accompanied by a degradation of starch and an increase of neutral lipids content. The onset of the death phase occurs after the 12 th day and is characterized by the loss of cell membrane integrity of some algae (cell death). The culture stays, progressively, yellow, and the majority of the population (~93%) is composed of live cells, chronologically “old,” with a significant drop in photosynthetic activity (decay > 75% of Fv/Fm and ɸ PSII ) and starch content. The information here achieved can be helpful when exploring the potential of this alga in toxicity studies or in biotechnological applications. Key points • Physiological changes of P. subcapitata with chronological aging are shown • “Young” algae exhibit a semilunar shape, high photosynthetic activity, and accumulated starch • “Old”-live algae show reduced photosynthetic capacity and accumulated lipids Graphical Abstract

In this study, the toxicity of three compounds of emerging concern (CEC) belonging to different classes [metolachlor (herbicide), erythromycin (antibiotic) and triclosan (antiseptic)], were evaluated and compared using the freshwater alga Pseudokirchneriella subcapitata and the marine alga Dunaliella tertiolecta. Toxicity assays were performed by exposing algal cells, in exponential phase of growth, to the toxicants for 72 h (P. subcapitata) or 96 h (D. tertiolecta). The toxicant concentrations that induced an inhibition of 50% of algal growth (EC50) of P. subcapitata or D. tertiolecta were 118 and 11.3 × 103 μg L−1 for metolachlor (MTC), 38 and 5.75 × 103 μg L−1 for erythromycin (ERT) and 27.1 and 93 μg L−1 for triclosan (TCS), respectively. Based on these EC50 values, it was possible to hierarchize (decreasing order) the toxicity of the CEC studied: TCS > ERT > MTC. The EC50 values achieved for P. subcapitata were between 3.4- and 151-fold lower than those observed with D. tertiolecta, which demonstrated the higher sensitivity of the freshwater alga comparatively to the marine alga. All 72 h-EC10 or 72 h-EC50 values determined in this study with P. subcapitata are within the concentration range of these pollutants described in the literature, in ground and surface waters, which underlines the significance of this alga in the ecotoxicity assessment of freshwaters.

Pharmaceuticals can be found in the aquatic environment and cause unwanted effects on organisms. The present work aimed to characterize the toxic mode of action of the antidepressant fluoxetine (FLX) on the freshwater microalga Raphidocelis subcapitata. With this aim, the microalga was exposed to low levels (µg/L) of FLX for 72 h. Exposure to 20–30 µg/L FLX arrested algal growth, which can be explained by the blockage of algal nuclear division. In addition, FLX (15–30 µg/L) deeply altered the alga’s metabolism, which was reflected by an increase in esterase activity, mitochondrial dysfunction (hyperpolarization of inner mitochondrial membrane), and reduction in the content of photosynthetic pigments: chlorophyll a (chla) and carotenoids (car). A sharp decline in photosynthetic performance, revealed by the reduction in maximum photochemical quantum yield (Fv/Fm), effective photochemical quantum yield (ΦPSII), and photosynthetic electron transport rate (ETR) of photosystem II (PSII), was also observed. FLX, at 30 µg/L, induced the intracellular accumulation of reactive oxygen species (ROS) and lipid peroxidation, with a marginal loss (1%) of cell membrane integrity. The results presented here contribute to the elucidation of the toxic mode of action of FLX on the microalgae R. subcapitata and, simultaneously, warn of the negative impact of the presence of pharmaceutical compounds in freshwater aquatic environments.

This study investigated the fatty acid profile, permeability, and metabolic effects of a functional yogurt enriched with pomegranate oil, focusing on its impact on lipid metabolism and inflammatory responses. The yogurt’s fatty acid composition was primarily composed of long-chain polyunsaturated fatty acids (54.37%), followed by saturated (29.34%) and monounsaturated fatty acids (16.36%). During in vitro digestion, a shift in fatty acid profile was observed, with a decrease in polyunsaturated and saturated fatty acids and a slight increase in monounsaturated fatty acids due to hydrolysis. This study further analyzed fatty acid permeability across Caco-2/HT29-MTX monolayers and 3T3-L1 cell uptake, revealing higher permeability for saturated fatty acids than unsaturated ones. In 3T3-L1 cells, permeated fatty acids induced higher lipolysis and increased adiponectin secretion without affecting leptin levels. Cytokine analysis indicated a decrease in pro-inflammatory markers, such as MCP-1, and a significant increase in anti-inflammatory cytokines like IL-10, suggesting potential benefits in reducing obesity-related inflammation. These results underscore the role of functional yogurts enriched with polyunsaturated fatty acids as promising agents for modulating lipid metabolism and inflammatory responses.

Sweet potato leaves (SPL), an agricultural byproduct, hold significant potential in dermatological applications due to their bioactive compounds. This study evaluates the phenolic profile of SPL extracts and investigates their biological activities relevant to skin health. Extract fingerprinting, through uHPLC-DAD and LC–MS, identified phenolic acids and flavonoids, with cynarin, neochlorogenic acid, and spiraeoside being predominant. The presence of hyperoside was detected. From a biological standpoint, SPL demonstrated notable antimicrobial activity, with MICs ranging from 2.5 to 5 mg/mL against various bacterial strains, such as MRSA and P. aeruginosa, and effective antibiofilm activity, as it reduced biofilm formation by over 80% for most tested strains. When evaluating its effect upon keratinocytes, the cytotoxicity assessment revealed safe usage concentrations at 111 µg/mL and immunomodulatory capacities, as it increased IL-6 production in unchallenged cells but had no synergistic effects under inflammatory stimuli. While preliminary, and with more assays being necessary, these findings highlight SPL’s potential as a natural agent for antimicrobial and anti-inflammatory applications in skin-related applications and open a new avenue for a possible added value application of SPL.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that is the result of various environmental, bacterial and genetic stimuli, which culminate in the disruption of the skin’s barrier function. Characterized by highly pruritic skin lesions, xerosis and an array of comorbidities among which skin infections are the most common, this condition results in both a significant loss of quality of life and in the need for life-long treatments (e.g., corticosteroids, monoclonal antibodies and regular antibiotic intake), all of which may have harmful secondary effects. This, in conjunction with AD’s rising prevalence, made the development of alternative treatment strategies the focus of both the scientific community and the pharmaceutical industry. Given their potential to both manage the skin microbiome, fight infections and even modulate the local immune response, the use of antimicrobial peptides (AMPs) from more diverse origins has become one of the most promising alternative solutions for AD management, with some being already used with some success towards this end. However, their production and use also exhibit some limitations. The current work seeks to compile the available information and provide a better understanding of the state of the art in the understanding of AMPs’ true potential in addressing AD.

Chronic skin inflammatory diseases including psoriasis and atopic dermatitis affect millions worldwide, imposing substantial physical, psychological, and economic burdens. Despite advances in topical therapies, conventional formulations suffer from poor skin penetration, rapid clearance, local and systemic side effects, and suboptimal patient adherence. Polymeric nanogels, internally crosslinked three-dimensional polymer networks with dimensions of 10–200 nm, emerged as promising platforms to overcome these limitations. Their unique properties including high water content, tunable porosity, biocompatibility, deformability, and stimulus-responsive behavior enhance skin penetration allowing for targeted therapeutic action. This review examines nanogel synthesis methods optimized for targeting skin inflammatory diseases, including biopolymer-based approaches utilizing chitosan and hyaluronic acid, offering insights into how different methods and advanced architecture provide multifunctional capacities and bioactivities. Translation challenges including manufacturing scalability, long-term safety assessment, and regulatory compliance are critically discussed alongside emerging opportunities in personalized medicine and smart microneedle integrated systems for adaptive therapy.

This work aimed to characterize the impact of copper (Cu), at environmentally relevant concentrations, using the freshwater microalga Raphidocelis subcapitata. Algae were incubated with 33 or 53 µg/L Cu, in OECD medium, and toxic impacts were evaluated over 72 h, using different cellular and biochemical biomarkers. The exposure to 33 µg/L Cu had an algistatic effect: slowing growth and reducing algal population (53%, at 72 h) without compromising the cell membrane. This Cu concentration promoted a transient reduction in chlorophyll a (chla) content and typical markers of oxidative stress: increased levels of reactive oxygen species (ROS), augmented catalase (CAT) activity, and lipid peroxidation (malondialdehyde, MDA). Algae exposed to 53 µg/L Cu, suffered a severe effect with a 93% reduction in the number of cells, 50% decrease in chla content, and diminished (17%) maximum photochemical quantum yield of PSII (Fv/Fm). This population also presented increased levels of ROS and MDA, 33 and 20 times higher than the control, respectively, at 72 h, augmented CAT activity, and permeabilized cell membrane (5%, at 72 h). These findings provide valuable insights into Cu toxicity in aquatic ecosystems, highlighting the biochemical and physiological impacts at environmentally relevant concentrations.