Removal of Heavy Metals (Cd2+, Cu2+, Ni2+, Pb2+) from Aqueous Solution Using Hizikia fusiformis as an Algae-Based Bioadsorbent

This study investigated the applicability of algae (Hizikia fusiformis, Green gracilaria, and Codium fragile) for removing heavy metals (Cd2+, Cu2+, Ni2+, and Pb2+) from aqueous solutions. Among the algae, H. fusiformis was chosen as a bioadsorbent and modified with NaOH and HCl. The results showed that the biosorption capacity of H. fusiformis improved significantly after treatment with NaOH; however, H. fusiformis modified with HCl did not achieve the expected value. The NaOH treatment enhanced the biosorption of metals on the treated H. fusiformis because of the hydrolysis reaction producing carboxylic (–COOH) and hydroxyl groups (–OH). The kinetics for Cd2+, Cu2+, Ni2+, and Pb2+ biosorption well fitted to pseudo-first-order, pseudo-second-order, and Elovich models, with R2 of >0.994. The Freundlich model provided a good fit for the equilibrium biosorption of Cd2+, Cu2+, and Ni2+ by both algae and the Langmuir model for Pb2+. The maximum biosorption of metals was in the order Pb2+ >> Cu2+ ≈ Ni2+ > Cd2+, with qmax of 167.73, 45.09, 44.38, and 42.08 mg/g, respectively. With an increase in the solution pH, metal biosorption was enhanced, and considerable enhancement was observed in the pH range of 2–4. Thus, H. fusiformis is expected to be considered a superior candidate for metal biosorption.

Hizikia fusiformis: Pharmacological and Nutritional Properties

The brown seaweed Hizikia fusiformis (syn. Sargassum fusiforme), commonly known as “Hijiki”, has been utilized in traditional cuisine and medicine in East Asian countries for several centuries. H. fusiformis has attracted much attention owing to its rich nutritional and pharmacological properties. However, there has been no comprehensive review of the nutritional and pharmacological properties of H. fusiformis. The aim of this systematic review was to provide detailed information from the published literature on the nutritional and pharmacological properties of H. fusiformis. A comprehensive online search of the literature was conducted by accessing databases, such as PubMed, SpringerLink, ScienceDirect, and Google Scholar, for published studies on the nutritional and pharmacological properties of H. fusiformis between 2010 and 2021. A total of 916 articles were screened from all the databases using the preferred reporting items for systematic reviews and meta-analyses method. Screening based on the setdown criteria resulted in 59 articles, which were used for this review. In this review, we found that there has been an increase in the number of publications on the pharmacological and nutritional properties of H. fusiformis over the last 10 years. In the last 10 years, studies have focused on the proximate, mineral, polysaccharide, and bioactive compound composition, and pharmacological properties, such as antioxidant, anticancer, antitumor, anti-inflammatory, photoprotective, neuroprotective, antidiabetic, immunomodulatory, osteoprotective, and gastroprotective properties of H. fusiformis extracts. Overall, further studies and strategies are required to develop H. fusiformis as a promising resource for the nutrition and pharmacological industries.

Polysaccharide from Hizikia Fusiformis Enhances the Immunomodulatory Activity of Macrophages

Background and Objectives: <i>Hizikia fusiformis</i> is widely used in oriental health food in Japan, China, and Korea, and is known for its anti-oxidation properties.Materials and Method: In this study, we investigated the anti-inflammatory and immune-modulatory effects and mechanisms of <i>Hizikia fusiformis</i> (<i>H. fusiformis</i>) extracts in lipopolysaccharide (LPS)-treated RAW 264.7 cells. RAW 264.7 cells were incubated in the presence of different concentrations of the viscozyme component of <i>H. fusiformis</i> (1, 2, 5, and 10 μg/mL), and changes in expression of pro-inflammatory cytokines (GM-CSF, iNOS, VEGF, and COX-2) were evaluated by real-time PCR and immunoblotting. In addition, the associated signaling pathway including phospho (p)-pNF-κB 65, p-pIkBa, p-p38, and p-p44/42 was also evaluated.Results: The viscozyme component of <i>H. fusiformis</i> downregulated the expression of GM-CSF, iNOS, VEGF, and COX-2 mRNA. The augmented NO and ROS production was decreased by administration of <i>H. fusiformis</i>. The signal intensity of p-pNF-κB 65, p-pIkBa, p-p38, and p-p44/42 protein activated by LPS was ameliorated by administration of the viscozyme fraction in RAW 264.7 cells.Conclusion: These results suggest that <i>H. fusiformis</i> has potential as a therapeutic agent for inflammatory diseases.

Saringosterol Acetate from a Popular Edible Seaweed, Hizikia Fusiformis Attenuated Proliferation of Human Lung Adenocarcinoma Epithelial Cells (A549 Cells) via Apoptosis Signaling Pathway

Hizikia fusiformis is a common, edible marine alga found in Asia. Although the anticancer activity of its extracts has previously been investigated, its active compounds have not been identified. In this study, saringosterol acetate (SA) was isolated from H. fusiformis extracts by centrifugal partition chromatography (CPC) system (two phase solvents condition: n-hexane:ethyl acetate/methanol:water = 5:3:7:1, v/v), exhibited anticancer effects in the human lung adenocarcinoma epithelial cell line, A549, by inducing apoptosis and sub-G1 phase cell cycle arrest. In addition, SA increased the expression of the pro-apoptotic proteins, Bax and cleaved caspase 3, and decreased that of the anti-apoptotic protein Bcl-xL. Although, SA did not affect the expression of p53, induces expression of Bid and caspase 8. In conclusion, we suggested that SA induces apoptosis against A549 cells via Bid and caspase 8 dependent pathway.

Experimental and Computational Study to Reveal the Potential of Non-Polar Constituents from Hizikia fusiformis as Dual Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitors

Hizikia fusiformis (Harvey) Okamura is an edible marine alga that has been widely used in Korea, China, and Japan as a rich source of dietary fiber and essential minerals. In our previous study, we observed that the methanol extract of H. fusiformis and its non-polar fractions showed potent protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase inhibition. Therefore, the aim of the present study was to identify the active ingredient in the methanol extract of H. fusiformis. We isolated a new glycerol fatty acid (13) and 20 known compounds including 9 fatty acids (1–3, 7–12), mixture of 24R and 24S-saringosterol (4), fucosterol (5), mixture of 24R,28R and 24S,28R-epoxy-24-ethylcholesterol (6), cedrusin (14), 1-(4-hydroxy-3-methoxyphenyl)-2-[2-hydroxy -4-(3-hydroxypropyl)phenoxy]-1,3-propanediol (15), benzyl alcohol alloside (16), madhusic acid A (17), glycyrrhizin (18), glycyrrhizin-6’-methyl ester (19), apo-9′-fucoxanthinone (20) and tyramine (21) from the non-polar fraction of H. fusiformis. New glycerol fatty acid 13 was identified as 2-(7′- (2″-hydroxy-3″-((5Z,8Z,11Z)-icosatrienoyloxy)propoxy)-7′-oxoheptanoyl)oxymethylpropenoic acid by spectroscopic analysis using NMR, IR, and HR-ESI-MS. We investigated the effect of the 21 isolated compounds and metabolites (22 and 23) of 18 against the inhibition of PTP1B and α-glucosidase enzymes. All fatty acids showed potent PTP1B inhibition at low concentrations. In particular, new compound 13 and fucosterol epoxide (6) showed noncompetitive inhibitory activity against PTP1B. Metabolites of glycyrrhizin, 22 and 23, exhibited competitive inhibition against PTP1B. These findings suggest that H. fusiformis, a widely consumed seafood, may be effective as a dietary supplement for the management of diabetes through the inhibition of PTP1B.