Conventional extraction of fucoidan from Irish brown seaweed Fucus vesiculosus followed by ultrasound-assisted depolymerization.

Fucoidan has attracted considerable attention from scientists and pharmaceutical companies due to its antioxidant, anticoagulant, anti-inflammatory, anti-tumor, and health-enhancing properties. However, the extraction of fucoidan from seaweeds often involves the use of harsh chemicals, which necessitates the search for alternative solvents. Additionally, the high viscosity and low cell permeability of high molecular weight (Mw) fucoidan can limit its effectiveness in drug action, while lower Mw fractions exhibit increased biological activity and are also utilized as dietary supplements. The study aimed to (1) extract fucoidan from the seaweed Fucus vesiculosus (FV) using an environmentally friendly solvent and compare it with the most commonly used extraction solvent, hydrochloric acid, and (2) assess the impact of ultrasound-assisted depolymerization on reducing the molecular weight of the fucoidan extracts and examine the cytotoxic effect of different molecular weight fractions. The findings indicated that the green depolymerization solvent, in conjunction with a brief ultrasound treatment, effectively reduced the molecular weight. Moreover, a significant decrease in cell viability was observed in selected samples, indicating potential anticancer properties. As a result, ultrasound was determined to be an effective method for depolymerizing crude fucoidan from Fucus Vesiculosus seaweed.

Sequential extraction of fucoidan, laminarin, mannitol, alginate and protein from brown macroalgae Ascophyllum nodosum and Fucus vesiculosus.

The study involves development of a green biorefinery process for obtaining fucoidan, laminarin, mannitol, alginate and protein from dry and fresh Fucus vesiculosus and Ascophyllum nodosum using hydrochloric acid and a green extraction solvent. After the extraction of fucoidan which was the targeted biomolecule, an extract and by-product (residual biomass) were obtained. The extract was passed through an ultrafiltration membrane, where fucoidan was obtained in the ultrafiltration retentate while ultrafiltration permeate was analysed for laminarin and mannitol. The residual biomass was used for obtaining alginate using ultrasound (20 kHz, 64 % amplitude and 32 min, optimum parameters for alginate extraction based on our previous study). All the samples, showed good results for alginate, laminarin and mannitol, indicating that the by-products can be utilised using this green extraction process. The comparison of both dry and fresh seaweed is relevant from an industry perspective, as fresh seaweed can directly be used for extraction, avoiding drying which adds significantly to the cost of the process. Life cycle impact assessment of the complete seaweed value chain has been carried out to identify the energy demand and key environmental hotspots. This biorefinery process can be used by industry to improve their processes and utilise the by-products generated efficiently.

Influence of molecular weight fractionation on the antimicrobial and anticancer properties of a fucoidan rich-extract from the macroalgae Fucus vesiculosus.

The objective of this study was to investigate the antimicrobial and anticancer properties of a fucoidan extract and subsequent fractions isolated from the macroalgae Fucus vesiculosus. The fractions obtained (>300 kDa, <300 kDa, <100 kDa, <50 kDa and <10 kDa) could inhibit the growth of B. subtilis, E. coli, L. innocua and P. fluorescens when assayed at concentrations between 12,500 and 25,000 ppm. The bacterial growth was monitored by optical density (OD) measurements (600 nm, 24 h) at 30 °C or 37 °C, depending upon on the strain used. The extracted fractions were also tested for cytotoxicity against brain glioblastoma cancer cells using the Alamar Blue assay for 24 h, 48 h and 6 days. The >300 kDa fraction presented the lowest IC50 values (0.052% - 24 h; 0.032% - 6 days). The potential bioactivity of fucoidan as an antimicrobial and anticancer agent was demonstrated in this study. Hence, the related mechanisms of action should be explored in a near future.

The development of analytical methods for the purity determination of fucoidan extracted from brown seaweed species.

To determine the purity of extracted fucoidan from brown seaweeds, analytical methods were developed, including spectroscopy (i.e., Attenuate total reflectance (ATR) - Fourier-transform infrared (FT-IR) and Raman) combined with chemometrics; and the results were compared with those of high performance liquid chromatography (HPLC) and other two chemistry methods (i.e., fucoidan estimation based on fucose content and a cationic dye method based on sulphated polysaccharide estimation). Quantitative models (i.e., partial least squares regression (PLSR)) were developed and cross-validated using FT-IR spectroscopic methods (R2CV ~ 0.998, RMSECV ~1.7%). The models were also validated using other four commercial fucoidan products. On the other hand, the same commercial samples were used to validate the two chemistry methods and the HPLC method. Estimation results of these analytical methods were discussed based on the potential of these analytical methods for fucoidan purity determination. The results demonstrated FT-IR spectroscopy with chemometrics potentially could be used for non-destructive and real time determination.

Green extraction of polyphenolic-polysaccharide conjugates from Pseuderanthemum palatiferum (Nees) Radlk.: Chemical profile and anticoagulant activity.

In this study, pressurized liquid extraction (PLE) of polyphenolic-polysaccharide (PP) from Pseuderanthemum palatiferum (Nees) Radlk. leaves was carried out and compared with a conventional technique using 0.1 M sodium hydroxide. The extracts were purified according to the method reported previously to obtain PP conjugates which were further studied about chemical profiles and anticoagulant activity. Fourier-transform infrared spectroscopy (FTIR), UV-Vis, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and spectrophotometry analysis were used to characterize the selected PP conjugates. The results showed that PP conjugates comprised of carbohydrate, phenolic, and protein constituents with the yield ranged from 2.76% to 14.34%. Seven mono sugars containing in all conjugates were determined using high-performance liquid chromatography (HPLC), namely, arabinose, fucose, galactose, glucose, mannose, rhamnose, and xylose. PP conjugates obtained from PLE at 150 °C (PP-PLE5) exhibited better anticoagulant activity than those found at 200 °C and comparable to that of the conventional technique. On gel permeation chromatography, PP-PLE5 showed a broad molecular mass from 6 to 642 kDa. From the obtained results, PLE can be used as a green effective technique for the recovery of PP conjugate from P. palatiferum leaves.

Combination of emerging technologies for the extraction of bioactive compounds.

With the growing consumer demands for greener alternatives that do not involve toxic chemicals as well as the industry concerns of sustainable, nontoxic routes of extraction, the applications of novel extraction technologies in the food industry have been widely studied. This review discussed the novel extraction technologies including their mechanisms, protocols, influencing factors, advantages and drawbacks, as well as a comprehensive summary of the combination of the novel extraction technologies for phyto-bioactive compounds. Novel extraction methods, including ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and enzyme-assisted extraction (EAE), are considered as clean, green and efficient alternative to conventional extraction technologies. Their combinations, ultrasound-assisted enzymatic extraction (UAEE), microwave-assisted enzymatic extraction (MAEE) and ultrasonic microwave-assisted extraction (UMAE), can exhibit higher potential extraction ability. However, some of them need specific equipment. The food industry in the extraction sector should choose a proper extraction method which has a balance between product quality, process efficiency, production costs and environmentally friendly processes. The current review presented comprehensive references for future research on the novel extraction of phyto-bioactive compounds extraction.HighlightsNovel clean, green and efficient alternative to conventional extraction technologies are discussed.Combination of the novel extraction technologies for synergistic effects.Minimal degradation and enhanced extraction yields.Extraction mechanisms, advantages and drawbacks associated with novel extraction technologies.

Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction.

The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone-methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.