Hearing loss is one of the most common sensory disorders in humans, and a large number of cases are due to ear cell damage caused by ototoxic drugs including anticancer agents, such as cisplatin. The recent literature reported that hearing loss is promoted by an excessive generation of reactive oxygen species (ROS) in cochlea cells, which causes oxidative stress. Recently, polysaccharides from the cyanobacterium Arthrospira platensis showed many biological activities, including antioxidant activity, suggesting their potential use to combat hearing loss. On these bases, this study describes the extraction, purification, and characterization of water-soluble polysaccharides from A. platensis (SPPs) and the investigation of their protective role against cisplatin toxicity on House Ear Institute-Organ of Corti (HEI-OC1) cells. The results showed that SPPs (5–80 µg/mL) induced a dose-dependent increase in viability, statistically significant at 40 µg/mL and 80 µg/mL. Moreover, SPPs, evaluated at 80 µg/mL, inhibited the cisplatin-induced ROS level increase in HEI-OC1. This evidence highlights the potential of SPPs as natural candidates to protect cochlear ear cells against ototoxic oxidative agents. Moreover, in view of the potential use of microalgal polysaccharides to realize hydrogels, SPPs could also represent a healthy carrier for other topically administered otoprotective agents.

Background/Objectives: Sulfated polysaccharides from Spirulina platensis have shown various promising biological activities, but their anticancer effects in lung cancer models remain poorly characterized. In this study, sulfated polysaccharide-rich fractions (SPPs) were tested on A549 non-small cell lung cancer (NSCLC) cells to evaluate their cytotoxic, oxidative, and immunomodulatory activity. Methods: The potential of SPPs to interfere with A549 cell viability, to modulate intracellular reactive oxygen species (ROS) levels, to produce pro-inflammatory effects, and to induce apoptosis was evaluated. Co-administration experiments were also performed using Gefitinib, a drug commonly used in NSCLC therapy. Non-cancerous human bronchial epithelial cells (16HBE) were included to assess the ability of SPPs to selectively target tumoral cells. Results: Our findings show that SPPs significantly reduced A549 cell viability in a concentration-dependent manner and increased ROS levels. This effect was associated with apoptotic DNA fragmentation and modulation of apoptosis-related genes, including upregulation of BAX and CASP-9, and downregulation of BCL-2, MTOR, and BIRC5. SPPs also induced a controlled pro-inflammatory response by increasing ACE2, NF-κB1, and CCL2 expression while reducing COX-2 levels. In co-administration experiments with Gefitinib, a cancer drug used to treat NSCLC, enhanced cytotoxic and pro-apoptotic effects were observed. Importantly, at active concentrations (150–250 µg/mL) SPPs were not found to produce cytotoxicity or apoptosis in 16HBE cells. Conclusions: Overall, these findings suggest that SPPs may selectively target NSCLC cells by promoting redox imbalance, apoptosis, and immune response, without affecting healthy cells, supporting their potential as natural adjuvants in lung cancer treatment.

Background/Objectives: Natural polysaccharides have many bio-pharmacological effects, which make them compounds with potential in healthcare. Limnospira platensis (Spirulina), a well-known blue–green cyanobacterium with relevance in the market of nutraceuticals, produces polysaccharides with recognized antioxidant and anti-inflammatory activities. Noteworthy, the growth of the cyanobacterium biomass may be obtained in a more sustainable manner under mixotrophic conditions. In the present study, we compared the antioxidant and anti-inflammatory effects of polysaccharide-enriched extracts from the cyanobacterium cultured under autotrophism (Auto−P extract) or mixotrophism (Mixo−P extract); this latter was realized using medium added with brewery wastewater (BWW). Methods and Results: Non-cellular investigation showed a better antioxidant profile for Mixo−P extract in the OH radical scavenging assay and a similar activity between the extracts in ABTS and ferrous chelation assays. The antioxidant protective activity of L. platensis extracts investigated on HaCat cells in the range of 0.3–10 μg/mL (not cytotoxic concentrations), against hydrogen peroxide (H₂O₂, 600 μM)-induced damage, revealed a similar activity by the two extracts. When tested against the inflammatory stimuli with lipopolysaccharide (LPS, 10 μg/mL) or tumor necrosis factor-α (TNF-α, 10 ng/mL), both Auto−P and Mixo−P showed an ability to prevent the effects of the inflammatory agents on cell viability and on interleukin-1β (IL-1β) and interleukin-6 (IL-6) release, with a slightly greater potency by Mixo−P extract. Conclusions: In conclusion, our data suggest the possible use of L. platensis polysaccharide-enriched extracts in biological-made pharmaceuticals for skin disorders or in cosmeceuticals. In addition, this study demonstrates that mixotrophic cultivation of L. platensis may be an alternative and sustainable way for biotechnological applications of the cyanobacterium biomass.

Polysaccharides derived from cyanobacteria and microalgae have attracted increasing interest as natural virucidal agents. Among them, polysaccharides from the cyanobacterium Arthrospira platensis (A. platensis), and the green microalgae Dunaliella salina (D. salina) have shown virucidal activities, mainly against enveloped viruses, while evidence on non-enveloped viruses is still limited. In this study, the virucidal activity of purified polysaccharides extracted from A. platensis (APPs) and from D. salina (DSPs) was evaluated in vitro against human adenovirus type 5 (HAdV5), a non-enveloped pathogenic virus with high persistence in the environment and resistance to disinfection. The in vitro assays were carried out at concentrations previously verified as non-toxic by morphological evaluation of A549 cells after 24 and 48 h of incubation, testing two viral loads, namely, 10³ and 10⁴ tissue culture infectious dose 50% per milliliter (TCID₅₀/mL). For APPs, a possible time-dependent effect was also assessed at different contact times (15, 30 and 60 min). DSPs showed a limited virucidal effect related to the starting viral concentration, while APPs induced a consistent viral reduction (up to 98.8%) at both viral concentrations. The virucidal effect of APPs occurred rapidly and was not significantly influenced by contact time, thus suggesting that prolonged exposure is not a determining factor for polysaccharide virucidal activity. These findings demonstrate the virucidal activity of APPs against a highly resistant non-enveloped virus and provide preliminary in vitro evidence of their potential application as natural virucidal agents, particularly for environmental disinfection purposes. Further investigations are warranted to elucidate the underlying mechanisms of action and to optimize their practical use.

Background: Pomegranate peel, a major by-product of the food industry, represents an underexploited source of valuable bioactive compounds. In the framework of a circular economy approach, this study aimed to develop a sustainable and solvent-free extraction strategy based on Saccharomyces cerevisiae fermentation for the recovery of antioxidant and antimicrobial phytochemicals from pomegranate peel waste. Methods: Pomegranate peel was subjected to fermentation for 18, 24, 48, and 72 h, and the resulting extracts (YE_18h, YE_24h, YE_48h, and YE_72h), together with a conventionally obtained chemical extract (CE), were evaluated for their antioxidant activity. Based on its superior antioxidant activity, the extract obtained after 48 h of fermentation (YE_48h) was selected for ellagic acid quantification by HPLC and characterization by UHPLC-HRMS (Ultra-High-Performance Liquid Chromatography coupled to High-Resolution Mass Spectrometry). Antibacterial activity of YE_48h, in comparison with CE, was assessed against six Gram-positive and Gram-negative bacterial strains. Results: Among the fermented samples, the extract obtained after 48 h of fermentation (YE_48h) exhibited the highest antioxidant activity, showing an IC₅₀ value lower than that of a conventional chemical extract. Quantitative HPLC analysis revealed a remarkable enhancement in ellagic acid content, with YE_48h containing approximately 18-fold higher levels of ellagic acid than the conventional chemical extraction. UHPLC-HRMS fingerprinting further demonstrated the presence of additional bioactive phenolic compounds, including punicalagin isomers I and II and pedunculagin isomer I, which are known for their antioxidant and antimicrobial properties. The antibacterial assay demonstrated that fermentation modulated the antimicrobial profile of the extracts in a strain-dependent manner. Conclusions: S. cerevisiae-mediated fermentation is an efficient and environmentally friendly approach for the valorization of pomegranate peel by-products, enhancing the release of bioactive compounds while generating extracts with promising antioxidant and selective antibacterial properties.