Lambda Carrageenan Research Articles

Lambda carrageenan displays antiviral activity against the infectious pancreatic necrosis virus (IPNV) by inhibiting viral replication and enhancing innate immunity in salmonid cells

Sulfated polysaccharide lambda carrageenan (λ-CGN) was evaluated for its antiviral effect against IPNV using the in vitro infection model of CHSE-214 salmonid cells. A plaque reduction lysis assay revealed that λ-CGN has an IC50 of 0.9 μg⋅mL−1, CC50 > 128 μg⋅mL−1 and a Selectivity Index (SI) > 142. In comparison, iota, kappa carrageenans and lambda oligo-carrageenan (λ-OC) were less effective than λ-CGN against IPNV. λ-CGN showed no virucidal activity when applied directly to viral particles. Time of addition experiments showed that pre-treatment, co-treatment, and post-treatment with λ-CGN significantly reduced viral RNA copies in the cell supernatant. Additionally, a decrease in intracellular viral RNA was observed with pre-treatment and post-treatment, indicating an impact on different stages of viral replication. Polyacrylamide gel electrophoresis of IPNV genomic RNA in presence of λ-CGN showed a reduction in the level of viral genomic RNA. Confocal microscopy confirmed the intracellular localization of λ-CGN, suggesting that λ-CGN may inhibit the synthesis of IPNV genomic RNA. Moreover, cells pre-treated with λ-CGN showed an increased expression of innate immunity genes CXCL11, IL1β, IFNa, and IRF3. These findings highlight the need for further research to confirm the in vivo pharmacological potential of λ-CGN as a new antiviral agent in salmonids.

Competitive Binding of Methylene Blue to Calf Thymus DNA and Carrageenan: Implications for Sensor Development

Carrageenans are sulfated polysaccharides widely used in the food industry due to their excellent thickening, stabilising, and gelling properties. Objective: This study delves into two key aspects: 1) the binding interaction between the cationic dye methylene blue (MB) and carrageenan compared to other polyanions (alginate, starch, and Arabic gum), and 2) the competitive binding behavior of carrageenan and DNA for MB. Methods: Spectroscopy methods were employed to determine the total amount of carrageenan by utilising MB, which creates complexes with carrageenan. The investigation into the competitive binding between polysaccharides and double-stranded DNA modified with screen-printed electrodes (SPEs) (dsDNA/SPE) for methylene blue (MB) involved the addition of varying quantities of polysaccharide to a solution containing 100 µM MB after a 5-minute accumulation period. Subsequently, cyclic voltammograms were directly recorded to analyse the interactions. Results: Strong electrostatic binding between MB and carrageenan was confirmed using various techniques, including UV-vis, fluorescence, and cyclic voltammetry. Moreover, photoluminescence (PL) spectroscopy was more sensitive than Ultraviolet-visible (UV-vis) spectroscopy, detecting carrageenans in a linear range from 0.5-15 ppm, 2-15 ppm, with correlation coefficients 0.998, 0.997, respectively. Notably, the preference for binding increased with increasing sulfate content, following the order kappa > iota > lambda carrageenan, highlighting the crucial role of sulfate groups in complex formation. Additionally, carrageenan exhibited the strongest competitive binding towards MB at low concentrations compared to other tested polyanions, implying its effectiveness in hindering MB-DNA interactions. Conclusions: These findings pave the way for exciting developments in DNA biosensors. The sensitive colorimetric assay holds promise for the rapid and selective determination of carrageenan levels in food products. Moreover, the competitive binding between carrageenan and MB can be harnessed in DNA biosensors by monitoring changes in MB binding due to specific DNA sequences.

Study on Anti-Inflammatory Effects of and Muscle Recovery Associated with Transdermal Delivery of Chaenomeles speciosa Extracts Using Supersonic Atomizer on Rat Model.

Repetitive motion or exercise is associated with oxidative stress and muscle inflammation, which can lead to declining grip strength and muscle damage. Oleanolic acid and ursolic acid have anti-inflammatory and antioxidant properties and can be extracted from Chaenomeles speciosa through ultrasonic sonication. We investigated the association between grip strength declines and muscle damage induced by lambda carrageenan (LC) injection and exercise exposure in rats. We also assessed the reparative effects of transdermal pretreatment and post-treatment with C. speciosa extracts (CSEs) by using a supersonic atomizer. The half-maximal inhibitory concentration (IC50) of CSEs for cells was 10.5 mg/mL. CSEs significantly reduced the generation of reactive oxygen species and inflammatory factors (interleukin [IL]-6 and IL-1β) in in vitro cell tests. Rats subjected to LC injection and 6 weeks of exercise exhibited significantly increased inflammatory cytokine levels (IL-1β, TNF-α, and IL-6). Hematoxylin and eosin staining revealed inflammatory cell infiltration and evident muscle damage in the gastrocnemius muscle, which exhibited splitting and the appearance of the endomysium and perimysium. The treated rats' grip strength significantly declined. Following treatment with CSEs, the damaged muscles exhibited decreased IL-1β, TNF-α, and IL-6 levels and normal morphologies. Moreover, grip strength significantly recovered. Pretreatment with CSEs yielded an immediate and significant increase in grip strength, with an increase of 180% and 165% occurring in the rats exposed to LC injection and exercise within the initial 12 h period, respectively, compared with the control group. Pretreatment with CSEs delivered transdermally using a supersonic atomizer may have applications in sports medicine and training or competitions.

Understanding the rheological properties from linear to nonlinear regimes and spatiotemporal structure of mixed kappa and reduced molecular weight lambda carrageenan gels

Blends of different carrageenan types have proven to be useful in tuning carrageenan gels' rheological properties. However, understanding the influence of a reduced molecular weight on the gelation of mixed carrageenan gels is still limited. Here, the gelation of mixed kappa-(KC) and reduced molecular weight lambda-(LC) carrageenan systems at different mixing ratios was evaluated using rheology from linear to nonlinear regimes via large amplitude oscillatory shear (LAOS), small-angle X-ray scattering (SAXS), pulsed nuclear magnetic resonance (NMR) and particle tracking. A single-step increase in moduli was seen for mixed kappa-lambda carrageenan (KCLC) gels with decreasing temperature while LC demonstrated nongelling behavior. The LAOS response of KCLC mixed gels showed the characteristic signature of strain-stiffening corresponding to the difference in the size and dynamics of the aggregates. The cross-sectional size revealed by SAXS and dynamics of the aggregates revealed by pulsed-NMR demonstrate that KCLC gels has higher segmental mobility and formed small aggregates that reduce with decreasing the KC fraction whereas pure KC gels formed large and rigid aggregates. Thus, the spatiotemporal features of the aggregates are considered to be the origin of the strain-stiffening in mixed gels under large deformation. Moreover, the microscopic properties of the KCLC gels evaluated using particle tracking revealed a homogenous network suggesting the formation of a swollen KC network in the LC solution. Hence, our findings provide insights into the rheological behavior and network structure design of KC and reduced molecular weight LC mixed gels.

Low-cost and eco-friendly PVA/carrageenan membrane to efficiently remove cationic dyes from water: Isotherms, kinetics, thermodynamics, and regeneration study

Methylene blue (MB), a common dye in the textile industry, has a multitude of detrimental consequences on humans and the environment. Accordingly, it is necessary to remove dyes from water to guarantee our health and sustainable ecosystem. In this study, we developed polyvinyl alcohol (PVA)-based hydrogel adsorbents with high adsorption capacity by adding three types of carrageenan (kappa, iota, and lambda) to remove MB from water. Thanks to the functional groups, the PVA/carrageenan membranes dramatically increased the removal efficiency (kappa, 98.8%; iota, 97.0%; lambda, 95.4%) compared to the pure PVA membrane (6.3%). Among the three types of PVA/carrageenan membranes, the PVA/kappa-carrageenan membrane exhibited the best adsorption capacity of 147.8 mg/g. This result implies that steric hindrance was considerably significant, given that kappa carrageenan has only one sulfate group in the repeating unit, whereas iota and lambda carrageenan composite PVA membranes possess two and three sulfate groups. Apart from the maximum adsorption capacity, this study addressed a variety of characteristics of PVA/carrageenan membranes such as the effects of initial MB concentration, kappa carrageenan weight percentage, contact time, adsorbent dosage, and temperature on the adsorption performance. In addition, the kinetic and thermodynamic studies were also carried out. Lastly, the reusability of the PVA/carrageenan membrane was verified by the 98% removal efficiency maintained after five adsorption-desorption cycles.

Selective Sorption of Heavy Metals by Renewable Polysaccharides.

Renewable and biodegradable polysaccharides have attracted interest for their wide applicability, among them their use as sorbents for heavy metal ions. Their high sorption capacity is due mainly to the acidic groups that populate the polysaccharide backbone, for example, carboxylic groups in alginate and sulfate ester groups in the iota and lambda carrageenans. In this study, these three polysaccharides were employed, alone or in different mixtures, to recover different heavy metal ions from aqueous solutions. All three polysaccharides were capable of adsorbing Eu3+, Sm3+, Er3+, or UO22+ and their mixtures, findings that were also confirmed using XPS, TGA, and FTIR analyses. In addition, the highest sorption yields of all the metal ions were obtained using alginate, alone or in mixtures. While the alginate with carboxylic and hydroxyl groups adsorbed different ions with the same selectivity, carrageenans with sulfate ester and hydroxyl groups exhibited higher adsorption selectivity for lanthanides than for uranyl, indicating that the activity of the sulfate ester groups toward trivalent and smaller ions was higher.

Carrageenan-induced inflammation elicits behavioral changes in cockatiels (Nymphicus hollandicus) for potential pain scale development.

To evaluate behaviors associated with inflammatory pain induced by carrageenan injection in the cockatiel and determine interobserver agreement. 16 adult cockatiels. Cockatiels were randomly assigned as either treatment (carrageenan injection) or control (sham injection) group. The treatment group received a subcutaneous injection of 0.05 mL of a 1% lambda carrageenan solution into the left footpad. Following treatment or control procedures, all cockatiels were video recorded individually for 9.5 hours. Ten minutes of video at each of 11 time points postinjection and/or handling were evaluated by 3 different observers. Twenty-five behaviors within 6 categories (resting, locomotion, maintenance, intake, interaction with environment, and limb and body posture) were assessed, in addition to crest position and mentation. Differences in individual behaviors tallies were assessed using serial Wilcoxon sum rank tests. Interobserver agreement was assessed using an intraclass correlation coefficient for a 2-way design for consistency among multiple observers. Treatment cockatiels exhibited significantly increased focal preening (q = .023) and increased burst preening (q = .036), while control cockatiels spent significantly more time in an upright stance (q = .036). Although the remainder of behaviors observed were not statistically significant between groups, additional variables of interest seen more frequently in treatment cockatiels included non-weight-bearing stance, holding of the body low, and being nonvigilant. The level of agreement between observers was variable based on the specific behaviors; nevertheless, the dynamic behaviors were substantial to strong. Carrageenan-induced inflammation-associated behaviors may be valuable in developing a pain scale and evaluating mild inflammatory pain in small psittacine species.

Carrageenans as Sustainable Water-Processable Binders for High-Voltage NMC811 Cathodes.

Poly(vinylidene fluoride) (PVDF) is the most common binder for cathode electrodes in lithium-ion batteries. However, PVDF is a fluorinated compound and requires toxic N-methyl-2-pyrrolidone (NMP) as a solvent during the slurry preparation, making the electrode fabrication process environmentally unfriendly. In this study, we propose the use of carrageenan biopolymers as a sustainable source of water-processable binders for high-voltage NMC811 cathodes. Three types of carrageenan (Carr) biopolymers were investigated, with one, two, or three sulfonate groups (SO3-), namely, kappa, iota, and lambda carrageenans, respectively. In addition to the nature of carrageenans, this article also reports the optimization of the cathode formulations, which were prepared by using between 5 wt % of the binder to a lower amount of 2 wt %. Processing of the aqueous slurries and the nature of the binder, in terms of the morphology and electrochemical performance of the electrodes, were also investigated. The Carr binder with 3SO3- groups (3SO3-Carr) exhibited the highest discharge capacities, delivering 133.1 mAh g-1 at 3C and 105.0 mAh g-1 at 5C, which was similar to the organic-based PVDF electrode (136.1 and 108.7 mAh g-1, respectively). Furthermore, 3SO3-Carr reached an outstanding capacity retention of 91% after 90 cycles at 0.5C, which was attributed to a homogeneous NMC811 and a conductive carbon particle dispersion, superior adhesion strength to the current collector (17.3 ± 0.7 N m-1 vs 0.3 ± 0.1 N m-1 for PVDF), and reduced charge-transfer resistance. Postmortem analysis unveiled good preservation of the NMC811 particles, while the 1SO3-Carr and 2SO3-Carr electrodes showed damaged morphologies.

Carrageenan in Seaweed (Eucheuma sp.) and Use of Carrageenan in Fishery Food Products: A Review

Carrageenan is a hydrocolloid compound found in red seaweed (Rodhophyta). Carrageenan-producing sources are Eucheuma cottonii seaweed with kappa carrageenan type and Eucheuma spinoum with iota carrageenan type. Kappa carrageenan is widely used in food products because its availability is very abundant in nature compared to iota and lambda carrageenan types. The boiling method with an alkaline solution is a method that is often used in extracting carrageenan. Carrageenan has properties as a stabilizer, thickener, gelling agent, and emulsifier. Carrageenan is widely applied in the food and non-food sector. In food products, carrageenan functions as a food additive, thickener, and emulsifier, and can increase the protein and fiber content of a food product.

Kinetic Hydrate Inhibition by Lambda-Carrageenan and Its Synergistic Compositions with Ethylene Glycol, 4-Methyl-1-Pentanol, Polyvinylpyrrolidone, and Polyvinylcaprolactam

For the oil and gas industry to function smoothly, it is essential to have a continuous flow of oil and gas in pipelines without interruptions caused by hydrate blockages. Kinetic hydrate inhibitors (KHIs) are becoming popular as they offer safe and effective hydrate inhibition at low dosages (0.5–2 wt % of the water content). The current commercial KHIs are synthetic and poorly biodegradable, which causes disposal concerns for environmental regulators. The lack of natural, sustainable, and biodegradable KHIs opens the scope to develop natural and biodegradable KHI alternatives. This study investigates the use of a natural and biodegradable polysaccharide, lambda carrageenan (λ-crgn), as a standalone KHI and its combinations with biodegradable solvents mono ethylene glycol and 4-methyl-1-pentanol and commercial KHI polymers (PVP and PVCap) for improved biodegradability and performance. λ-crgn is an environmentally friendly polysaccharide derived and cultivated from red seaweeds. Two variants of λ-crgn, one with a smaller mean size and a lower viscosity (LV) and one with a larger mean size and a higher viscosity (HV), are tested for hydrate inhibition. The lower molecular size/viscosity variant, λ-crgn (LV), showed similar induction times and lower hydrate growth rates compared to PVP when used as a standalone KHI. However, the high-viscosity variant did not perform as well as PVP. λ-crgn (HV or LV), when blended with commercial KHIs (PVP and PVCap), synergized and led to an increase in induction times by up to 63% and a decrease in the hydrate growth rates by 73% compared to when only the commercial KHIs were used at the exact total dosages. When λ-crgn (HV or LV) was blended with solvents 4-methyl-1-pentanol or MEG, again a significant synergy was observed, leading to the hydrate inhibition performance that was found to be at par or better than the commercial KHIs (PVP and PVCap) at the exact total dosages.

Health impact of carrageenan and its application in food industry: a review

Carrageenan is used widely in food products especially for gelling, thickening, emulsifying agents, and to stabilize the food properties which is extracted from red and purple seaweeds that contain the mixture of polysaccharides. Based on the sulfate content, carrageenan is divided as kappa-carrageenan, iota-carrageenan, and lambda carrageenan. Even though it is used widely in the food industry, there is controversy about the health effects of using carrageenan in the food products such as may cause inflammation, glucose intolerance, insulin resistance, gastrointestinal ulcerations, and could damage the digestive system. According to this condition it is suggested to limit the usage of carrageenan in the food industry. The objective of this paper is to discuss the impact to health and application of carrageenan in the food industry.

Hydroethanolic Leaf Extract of Cordia vignei Hutch and Dalziel Inhibits Carrageenan-Induced Foot Oedema in Chicks, Prostaglandin E2-Induced Paw Oedema in Mice, and Bradykinin-Induced Paw Oedema in Mice.

Cordia vignei Hutch and Dalziel (Fam. Boraginaceae) is a woody plant found in west tropical Africa. The aim of this research is to find out if the leaf extract of this plant prevents oedema in animal models. (a) Inflammation was induced in the animals by injecting 100 µl of 2% lambda carrageenan into the subplantar tissue of the right footpads of 7-day-old chicks 1 h before or after oral administration of 30-300 mgkg-1 CVE. Oedema was measured for 5 h using the water displacement method. (b) Oedema was induced in ICR mice by subplantar injection of prostaglandin E2 (PGE2) (50 µl of 1 nM) 30 minutes before or after CVE administration. Oedema was measured for 3 h. (c) Oedema was induced in ICR mice by subplantar injection of bradykinin (BK) (10 nmol/paw) 30 min before or after administration of extract. We found that CVE significantly (P < 0.05) prevented inflammation that was induced by injecting carrageenan into the footpads of the chicks. Also, we observed that CVE prevented inflammation produced by injecting PGE2 into the subplantar tissue of mice. Finally, we also report that CVE prevented inflammation produced by injecting BK into the subplantar tissues of mice. All these effects were observed in both preventive and curative protocols. We conclude that Cordia vignei leaf extract has potential anti-inflammatory activity.

Foaming properties are improved by interactions between brewer's spent grain proteins and carrageenans in aqueous solution.

Foaming properties and macromolecular interactions in solution among brewer's spent grain proteins (CP) and iota and lambda carrageenans (i-CG and l-CG, respectively) as a function of aqueous medium pH (2-6) and protein-polysaccharide ratio, RCP:CG (1:1, 2:1 and 4:1), were studied. At these conditions, the CP colloidal stability was favored by the formation of soluble electrostatic complexes with CG. Fluorescence (intrinsic and extrinsic) spectroscopy and dynamic light scattering techniques, including particle size and ζ-potential analysis, were applied to know the phase behavior of the biopolymer systems. The bubbling method was used to produce foams, and the foam expansion (%) and half-life time (t1/2 ) were determined. Both CG promoted an increased Trp fluorescence emission depending on the pH, suggesting conformational changes in CP. The CG in mixed systems produced a significant decrease in the extrinsic fluorescence intensity, mainly at low pH values, highlighting a reduction in CP surface hydrophobicity. At the examined pH range, the ζ-potential values for mixed-systems were negative, and their magnitudes were intermediate between CP and CG, revealing the associative electrostatic nature of biopolymer interactions, which were dependent on the RCP:CG . The particle size analysis confirmed the formation of soluble electrostatic complexes in solution. Finally, using i-CG at pH 2 or 3 and 2:1 RCP:CG , the best foaming properties for mixed systems were observed. The formation of electrostatic complexes with a compact assembly among biopolymers, high negative net charge, and colloidal stability convert the CP-CG mixed solutions into promising biopolymer systems for food foams production. © 2022 Society of Chemical Industry.

Lambda Carrageenan as a Water-Soluble Binder for Silicon Anodes in Lithium-Ion Batteries

Lambda Carrageenan as a Water-Soluble Binder for Silicon Anodes in Lithium-Ion Batteries

Evaluation of weight-bearing, locomotion, thermal antinociception, and footpad size in a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus).

To evaluate a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus) using weight-bearing load, rotational perch locomotion, thermal threshold withdrawal, and footpad dimensions. 16 adult cockatiels (8 males and 8 females). Cockatiels were randomly assigned into 2 groups as either treatment (carrageenan injection; n = 8) or control (handling only; 8). Treatment of cockatiels involved unilateral subcutaneous injection of 0.05 mL of 1% lambda carrageenan solution into the left footpad. Control birds were handled in a similar manner without an injection. Following baseline measurements and treatment or control procedures, posttreatment measurements at multiple time points involving weight-bearing perch load (for up to 336 hours), locomotive abilities when placed on a rotating perch (for up to 96 hours), thermal withdrawal threshold (for the 24- to 30-hour period), and both vertical and horizontal left footpad size and degree of swelling (for up to 84 days) were obtained. Treatment cockatiels had a significant decrease in left foot weight-bearing load and increase in left footpad dimensions and swelling grade over time compared to control cockatiels. Rotational perch locomotion and thermal withdrawal threshold, conversely, did not differ significantly between groups. Cockatiels injected with carrageenan returned to normal weight-bearing within 2 weeks; however, left footpad dimensions did not return to baseline. Carrageenan footpad injection prompts a measurable and grossly visible inflammatory response in the cockatiel. Additionally, it induces alterations in weight-bearing distribution in injected birds. This model provides a method to evaluate inflammation and lameness in small psittacine species.

Evaluation of seaweed sulfated polysaccharides as natural antagonists targeting Salmonella typhi OmpF: molecular docking and pharmacokinetic profiling

BackgroundSalmonella belongs to the Enterobacteriaceae family, a gram-negative, non-spore-forming, rod-shaped, motile, and pathogenic bacteria that transmit through unhygienic conditions. It is estimated that 21 million new infections arise every year, resulting in approximately 200,000 deaths. It is more prevalent among children, the old aged, and immunocompromised individuals. The frequent usage of classical antimicrobials has begun the increasing emergence of various drug-resistant pathogenic bacterial strains. Hence, this study was intended to evaluate the bioactive seaweed sulfated polysaccharides (SSPs) against the ompF (outer membrane porin F) protein target of Salmonella typhi. SSP is the sulfated compound with a wide range of biological activities, such as anti-microbial, anti-allergy, anti-cancer, anti-coagulant, anti-inflammation, anti-oxidant, and anti-viral.ResultsIn this study, eleven compounds were targeted against S. typhi OmpF by the molecular docking approach and were compared with two commercially available typhoid medications. The SSP showed good binding affinity compared to commercial drugs, particularly carrageenan/MIV-150, carrageenan lambda, fucoidan, and 3-phenyllactate, ranked as top antagonists against OmpF. Further, pharmacokinetics and toxicology (ADMET) studies corroborated that SSP possessed drug-likeness and highly progressed in all parameters.ConclusionsAutoDockTools and Schrodinger's QikProp module results suggest that SSP could be a promising drug for extensively drug-resistant (XDR) S. typhi. To the best of our knowledge, this is the first report on in silico analysis of SSP against S. typhi OmpF, thus implying the capabilities of SSPs especially compounds like carrageenans, as a potential anti-microbial agent against Salmonella typhi infections. Eventually, advanced studies could corroborate SSPs to the next level of application in the crisis of XDR microbial diseases.Graphical

An in vivo evaluation of anti-inflammatory, analgesic and anti-pyretic activities of newly synthesized 1, 2, 4 Triazole derivatives

BackgroundIn recent years, 1, 2, 4-triazole and its derivatives have been reported to be pharmacologically significant scaffolds. They possess analgesic, anti-tubercular, anti-inflammatory, anti-convulsant, anti-oxidant, anti-fungal, anti-cancer, anxiolytic and anti-depressant activity. This study was designed and conducted to evaluate the potential anti-inflammatory, analgesic and antipyretic activities of Triazole derivatives.MethodsSwiss albino (male and female) mice weighing 20-30 g (10-24 weeks female), (5-14 weeks male) and Wister Kyoto rats (male and female) weighing 200-300 g (8-10 weeks old) were used for the present study. Anti-inflammatory activity was checked using Lambda carrageenan (λ) and egg albumin-induced paw edema models. Analgesic via Writhing Reflex induced by acetic acid and formalin, furthermore anti-pyretic activity was assessed by yeast induced pyrexia.ResultsBoth of the test compounds exhibited encouraging anti-inflammatory analgesic and antipyretic results when compared with standard drug ibuprofen. The maximum inhibition of edema for the compound (S)-1-(4-Amino-5-mercapto-4H-1,2,4-triazole-3-yl) ethanol [3] was found to be (91)% as compared to reference drug ibuprofen (82)%, while (S)-1-(6-Phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanol [5e] showed equipotent results to ibuprofen (81)%. The derivatives were also screened for their anti-nociceptive activity by Acetic acid writhing and tail immersion test. Compound 3 showed a significant reduction in wriths (83)% as compared to standard drug ibuprofen 71.5% and [5] showed comparable results to ibuprofen by exhibiting 70% reduction in writh at the same dose as that of standard drug, moreover, there were no signs of toxicity being observed after administration of high doses of test compounds to mice.ConclusionsIt is evident from the results that compounds 3(compound A) and 5(compound B) are a potential candidate for anti-inflammatory, analgesic and anti-pyretic and the scaffold could be used for further structural modifications. Further studies would help to evaluate their molecular mechanism of action regarding these beneficial activities.

Binding of lambda carrageenan to bovine serum albumin and non-equilibrium effects of complexation

Binding of lambda carrageenan (lCG) to bovine serum albumin (BSA) and the effect of the formation path, namely mixing (M) at specific pH versus titration (T) from a neutral mixture, on complexation have been studied using turbidimetry, phase analysis, dynamic light scattering, confocal laser scanning and bright-field optical microscopy, circular dichroism and fluorescence measurements. The sizes and shape of the complex particles formed under T-conditions differ significantly from those obtained under M-conditions, and at maximal complexation T-complexes contain significantly less lCG as compared to M-complexes. At a pH below pIBSA phase analysis reveals two domains of q corresponding to an approximately constant lCG/BSA weight ratio in the complex phase q* (domain I), and a decreasing q* (domain II). Binding stoichiometries at pH 4.2 and 4.7 are 1:77 and 1:119 mole lCG/mole BSA. The yield of BSA in the complex phase is higher than 98% at pH 4.2 and 4.7, and the complexes form and are stable in the presence of 1.0M–1.5M NaCl. The interaction did not lead to protein denaturation or significant changes in the tertiary and secondary structure and illustrates an enhancement of the hydrophobicity of the protein within the complex particles. At pH 5.2 (pH on the wrong side of PIBSA) up to 37.6% BSA was bound to lCG, and the weight ratio of lCG/BSA in the complex particles (q*) was weakly dependent on q in the complete q range studied. The molecular origin of the unusually strong interaction between lCG and BSA is discussed.

Griffithsin and Carrageenan Combination Results in Antiviral Synergy against SARS-CoV-1 and 2 in a Pseudoviral Model.

Over 182 million confirmed cases of COVID-19 and more than 4 million deaths have been reported to date around the world. It is essential to identify broad-spectrum antiviral agents that may prevent or treat infections by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) but also by other coronaviruses that may jump the species barrier in the future. We evaluated the antiviral selectivity of griffithsin and sulfated and non-sulfated polysaccharides against SARS-CoV-1 and SARS-CoV-2 using a cytotoxicity assay and a cell-based pseudoviral model. The half-maximal cytotoxic concentration (CC50) and half-maximal effective concentration (EC50) were determined for each compound, using a dose-response-inhibition analysis on GraphPad Prism v9.0.2 software (San Diego, CA, USA). The therapeutic index (TI = CC50/EC50) was calculated for each compound. The potential synergistic, additive, or antagonistic effect of different compound combinations was determined by CalcuSyn v1 software (Biosoft, Cambridge, UK), which estimated the combination index (CI) values. Iota and lambda carrageenan showed the most potent antiviral activity (EC50 between 3.2 and 7.5 µg/mL). Carrageenan and griffithsin combinations exhibited synergistic activity (EC50 between 0.2 and 3.8 µg/mL; combination index <1), including against recent SARS-CoV-2 mutations. The griffithsin and carrageenan combination is a promising candidate to prevent or treat infections by SARS-CoV-1 and SARS-CoV-2.

Effect of the Anchoring Layer and Transport Type on the Adsorption Kinetics of Lambda Carrageenan.

The kinetics of lambda carrageenan (λ-car) adsorption/desorption on/from anchoring layers under diffusion- and convection-controlled transport conditions were investigated. The eighth generation of poly(amidoamine) dendrimers and branched polyethyleneimine possessing different shapes and polydispersity indexes were used for anchoring layer formation. Dynamic light scattering, electrophoresis, streaming potential measurements, optical waveguide lightmode spectroscopy, and quartz crystal microbalance were applied to characterize the formation of mono- and bilayers. The unique combination of the employed techniques enabled detailed insights into the mechanism of the λ-car adsorption mainly controlled by electrostatic interactions. The results show that the macroion adsorption efficiency is strictly correlated with the value of the final zeta potentials of the anchoring layers, the transport type, and the initial bulk concentration of the macroions. The type of the macroion forming the anchoring layer had a minor impact on the kinetics of λ-car adsorption. Besides significance to basic science, the results presented in this paper can be used for the development of biocompatible and stable macroion multilayers of well-defined electrokinetic properties and structure.