A comparative study of extraction methods for recovery of bioactive components from brown algae Sargassum serratifolium

Species of Sargassum genus are known to be rich sources of bioactive compounds. However, there is a lack of studies comparing extraction methods for these bioactive components. This study aimed to compare the total phenolic contents, total antioxidant capacity, tyrosinase inhibitory effect, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), two algal meroterpenoids, of Sargassum serratifolium extracts acquired by different extraction methods. The methods employed in this study included conventional solid-liquid extraction using methanol (SME), supercritical fluid extraction using CO2 with ethanol as a co-solvent (SC-CO2 + ethanol), and pressurized liquid extraction (PLE) at two temperatures (25 and 100 °C). PLE at 100 °C (PLE100) exhibited the highest total yield, total phenolic content, total antioxidant capacity and tyrosinase inhibitory activity. Notably, SME resulted in the highest recovery of both SHQA and SCM. Compared to SME, PLE100 exhibited a two-fold increase in antioxidant capacity but a minimal increase in phenolic content.

Nutritional composition and phenolic contents of Gracilariopsis longissima, Padina tetrastromatica and Ulva intestinalis from the Bay of Bengal, Bangladesh coast

Seaweeds have become the focus of experts in recent years due to their biological characteristics and the variety of uses they have for both humans and animals. Biochemical composition, amino acids, fatty acids, and phenolic components were analyzed to explore the nutritive value of Gracilariopsis longissima, Padina tetrastromatica, and Ulva intestinalis from the Bay of Bengal, Bangladesh coast. Proximate composition and mineral content were determined according to the AOAC method. The high-performance liquid chromatography amino acid analysis system was used for the amino acid analysis and the fatty acid profile of the extracted oils was assessed as their methyl esters. The Folin-Ciocalteu technique was used to estimate the phenolic content and the aluminum chloride colorimetric technique was used to calculate the total flavonoid content. The three different species of seaweed had significantly different proximate compositions (P < 0.05), with G. longissima having the highest protein content. Except for sulfur, the mineral contents were likewise considerably higher (P < 0.05) in G. longissima. Although the amounts of the essential amino acids were greater than 50 % of the total amino acids in the three studied seaweed species, the total amino acid composition of these three species differed significantly (P < 0.05). The findings indicated that lipid levels were low in all the assessed species, but unsaturated fatty acid levels were high, with G. longissima exhibiting the highest amounts. The results showed that, compared to the other species, G. longissima had a substantially higher (P < 0.05) level of total phenolic and flavonoid content. The three studied seaweed appear to be excellent for nutrition based on their overall nutritional profiles. However, due to high protein, unsaturated fatty acid, essential amino acid, and total phenolic and flavonoid content, G. longissima is the most promising seaweed that will be helpful for pharmaceutical and multifunctional food applications.

The Role of Sargahydroquinoic Acid and Sargachromenol in the Anti-Inflammatory Effect of Sargassum yezoense

The anti-inflammatory effect of the ethanol extract of Sargassum yezoense and its fractions were investigated in this study. The ethanol extract exhibited a strong anti-inflammatory effect on lipopolysaccharide-stimulated RAW 264.7 macrophages and effectively suppressed the M1 polarization of murine bone-marrow-derived macrophages stimulated by lipopolysaccharides and IFN-γ (interferon-gamma). Through a liquid-liquid extraction process, five fractions (n-hexane, chloroform, ethyl acetate, butanol, and aqueous) were acquired. Among these fractions, the chloroform fraction (SYCF) was found to contain the highest concentration of phenolic compounds, along with two primary meroterpenoids, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), and exhibit significant antioxidant capacity. It also demonstrated a robust anti-inflammatory effect. A direct comparison was conducted to assess the relative contribution of SHQA and SCM to the anti-inflammatory properties of SYCF. The concentrations of SHQA and SCM tested were determined based on their relative abundance in SYCF. SHQA contributed to a significant portion of the anti-inflammatory property of SYCF, while SCM played a limited role. These findings not only highlight the potential of the chloroform-ethanol fractionation approach for concentrating meroterpenoids in S. yezoense but also demonstrate that SHQA and other bioactive compounds work additively or synergistically to produce the potent anti-inflammatory effect of SYCF.

Suppression of Pro-Inflammatory M1 Polarization of LPS-Stimulated RAW 264.7 Macrophage Cells by Fucoxanthin-Rich Sargassum hemiphyllum

Macrophages play an important role in managing the onset and progression of chronic inflammatory diseases. The primary objective of this study is to explore the antioxidant potential and anti-inflammatory properties of Sargassum hemiphyllum ethanol extract (SHE) and its fraction. SHE and its five constituent fractions were assessed for overall antioxidant capabilities and inhibitory effects on LPS-induced inflammation by modulating macrophages polarization in both RAW 264.7 macrophages and bone-marrow-derived macrophages (BMDM). Among the organic solvent fractions of SHE, the ethyl acetate fraction displayed the highest total phenolic content and total antioxidant capacity. Notably, the n-hexane (Hex) fraction showed the most substantial suppression of LPS-induced tumor necrosis factor α secretion in BMDM among the five fractions of SHE. The SHE and Hex fraction significantly reduced the heightened expression of pro-inflammatory cytokines and inflammation-inducible enzymes induced by LPS in RAW 264.7 macrophages. In particular, the SHE and Hex fraction inhibited M1 macrophage polarization by reducing the mRNA expression of M1 macrophage markers in macrophages that were polarized toward the M1 phenotype. Furthermore, the SHE and Hex fraction attenuated the induction in nuclear factor E2-related factor 2 and its target genes, which was accompanied by an alteration in antioxidant gene expression in M1-polarized BMDM. The findings suggest that both SHE and its Hex fraction exhibit inhibitory effects on LPS-triggered inflammation and oxidative stress by modulating the polarization of M1 macrophages within macrophage populations.

Applications of Antioxidant Secondary Metabolites of Sargassum spp

Sargassum is one of the largest and most diverse genus of brown seaweeds, comprising of around 400 taxonomically accepted species. Many species of this genus have long been a part of human culture with applications as food, feed, and remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of natural antioxidant compounds of great interest, including polyphenols, carotenoids, meroterpenoids, phytosterols, and several others. Such compounds provide a valuable contribution to innovation that can translate, for instance, into the development of new ingredients for preventing product deterioration, particularly in food products, cosmetics or biostimulants to boost crops production and tolerance to abiotic stress. This manuscript revises the chemical composition of Sargassum seaweeds, highlighting their antioxidant secondary metabolites, their mechanism of action, and multiple applications in fields, including agriculture, food, and health.

Screening of antioxidant capacity of Nepali medicinal plants with a novel singlet oxygen scavenging assay

Pollutant exposure due to industrial development increases oxidative stress in human bodies. Dietary intake of antioxidant shows a protective effect against oxidative damage induced by oxidative stress. Therefore, the development of natural antioxidants is needed. In this study, the antioxidant activities of some Nepali medicinal plant extracts were measured. Using Rose bengal and 3,3',5,5'-tetramethylbenzidine, a novel assay was utilized to evaluate the singlet oxygen scavenging capacity, and showed a strong correlation with other antioxidant assays. Also, antioxidant capacities based on four assays including the singlet oxygen scavenging assay were highly correlated (≥ 0.858) with the total phenolic contents in the medicinal plant extracts. Among the selected extracts, Persicaria capitata, Elaphoglossum marginatum and Eurya acuminata showed the highest antioxidant capacities. Overall, this study presents a novel approach for evaluating singlet oxygen scavenging capacity, and performed a screening of antioxidant capacities of 54 Nepali herbal medicines.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01175-z.

Nutraceutical potential of polyphenol-rich Sargassum species grown off the Korean coast: a review

Sargassum, a brown seaweed, has been used traditionally as food and medicine in Korea, China, and Japan. Sargassum spp. contain bioactive substances associated with health benefits, including anti-inflammatory and antioxidant effects. Thirty Sargassum spp. inhabit the Korean coast. However, their health benefits have yet to be systematically summarized. Therefore, the purpose of this article was to review the health benefits of these 30 Sargassum spp. grown off the Korean coast based on their health benefits, underlying mechanisms, and identified bioactive compounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01050-x.

Cytotoxicity against Human Hepatocellular Carcinoma (HepG2) Cells and Anti-Oxidant Activity of Selected Endemic or Medicinal Plants in Sri Lanka

Hepatocellular carcinoma (HCC) is the most fatal cancer globally with limited treatment options. Plants and herbs have been used to treat cancer and other diseases for a long time by traditional practitioners in Sri Lanka. In the present study, leaf and bark extracts of selected plants were investigated for cytotoxic properties on HepG2 cells. Anti-oxidant activity and total phenolic and flavonoid contents were also determined. Plant extracts that exerted cytotoxic effects on the HepG2 cell line with IC₅₀ <100 μg/mL were tested on normal liver epithelial cells (THLE-3). Out of the 56 extracts, 21 exhibited potent cytotoxic effects (IC₅₀ < 100 µg/mL) on HepG2 cells after 48 h exposure, and 12 were less toxic (IC₅₀ > 100 μg/mL) to THLE-3 normal liver cells. Six extracts exhibited potent radical scavenging activity with EC₅₀ < 100 μg/mL against 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, while 17 extracts showed potent anti-oxidant activity (Trolox equivalents > 100 mg/g) against ferric reducing anti-oxidant power (FRAP) assay. Out of the 56 extracts, 15 had total phenolic content above 100 mg/g of gallic acid equivalents, and 4 had flavonoid content above 100 mg/g of quercetin equivalents. Among the extracts screened, hexane, dichloromethane, ethyl acetate, and methanol extracts of Allophylus cobbe leaves (IC₅₀ – 9.388, 6.8, 19.95, and 11.3 μg/mL, respectively), Madhuca longiflora bark (IC₅₀ – 14.42 μg/mL), methanol extract of Munronia pinnata bark (IC₅₀ – 52.06 μg/mL), and hexane, dichloromethane, ethyl acetate, and methanol extracts of Adenanthera bicolor (IC₅₀ – 45.86, 27.35, 24.56, and 61.83 μg/mL, respectively) exerted potent cytotoxicity against HepG2 with less toxicity (IC₅₀ > 100 μg/mL) to THLE-3 cells after 48 h of incubation. These findings provide a direction to isolate possible anti-cancer compounds for hepatocellular carcinoma.

Effect of particle size on phytochemical composition and antioxidant properties of Sargassum cristaefolium ethanol extract

Sample particle size is an important parameter in the solid-liquid extraction system of natural products for obtaining their bioactive compounds. This study evaluates the effect of sample particle size on the phytochemical composition and antioxidant activity of brown macroalgae Sargassum cristaefolium. The crude ethanol extract was extracted from dried powders of S.cristeafolium with various particle sizes (> 4000 µm, > 250 µm, > 125 µm, > 45 µm, and < 45 µm). The ethanolic extracts of S.cristaefolium were analysed for Total Phenolic Content (TPC), Total Flavonoid Content (TFC), phenolic compound concentration and antioxidant activities. The extract yield and phytochemical composition were more abundant in smaller particle sizes. Furthermore, the TPC (14.19 ± 2.08 mg GAE/g extract to 43.27 ± 2.56 mg GAE/g extract) and TFC (9.6 ± 1.8 mg QE/g extract to 70.27 ± 3.59 mg QE/g extract) values also significantly increased as particle sizes decreased. In addition, phenolic compounds epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and Epigallocatechin gallate (EGCG) concentration were frequently increased in samples of smaller particle sizes based on two-way ANOVA and Tukey's multiple comparison analysis. These results correlate with the significantly stronger antioxidant activity in samples with smaller particle sizes. The smallest particle size (< 45 µm) demonstrated the strongest antioxidant activity based on DPPH, ABTS, hydroxyl assay and FRAP. In addition, ramp function graph evaluates the desired particle size for maximum phytochemical composition and antioxidant activity is 44 µm. In conclusion, current results show the importance of particle size reduction of macroalgae samples to increase the effectivity of its biological activity.

Determination of Phenolic Content, Antioxidant Activity, and Tyrosinase Inhibitory Effects of Functional Cosmetic Creams Available on the Thailand Market

Recently, the global trend toward the use of natural extracts and antioxidant agents in the cosmetic cream industry to produce whitening effects has been increasing. This has also been a persistent trend in Thailand. In this study, samples of commercial cosmetic creams on the Thai market were assessed for a functional evaluation of their antioxidant activity, tyrosinase inhibitory effects, and phenolic contents. Samples were extracted using hot water and sonication extraction method to obtain the functional cream extracts. Total phenolic contents in all samples were within the range of 0.46-47.92 mg GAE/30 g cream. Antioxidant activities of the cream extracts were within the range of 3.61-43.98 mg Trolox equivalent/30 g cream, while tyrosinase inhibition activities were within the range of 2.58-97.94% of inhibition. With regard to the relationship between the total phenolic content and the antioxidant activity of the cosmetic creams, Pearson's correlation coefficient revealed a moderately positive relationship with an r value of 0.6108. Furthermore, the relationship between the antioxidant activity and the tyrosinase inhibitory activity of the cosmetic creams was highly positive with an r value of 0.7238. Overall, this study demonstrated that the total phenolic contents in the functional cosmetic creams could play a role in antioxidant activity and anti-tyrosinase activities. The findings indicate how the whitening and antioxidant effects of cosmetic creams could be maintained after the products have been formulated, as this concern can affect the consumer's decision when purchasing cosmetic products.