Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression

Brown Algae Dictyopteris divaricata Attenuates Adipogenesis by Modulating Adipocyte Differentiation and Promoting Lipolysis through Heme Oxygenase-1 Activation in 3T3-L1 Cells

The present study aims to explore the probable anti-adipogenesis effect of Dictyopteris divaricata (D. divaricata) in 3T3-L1 preadipocytes by regulating heme oxygenase-1 (HO-1). The extract of D. divaricata retarded lipid accretion and decreased triglyceride (TG) content in 3T3-L1 adipocytes but increased free glycerol levels. Treatment with the extract inhibited lipogenesis by inhibiting protein expressions of fatty acid synthase (FAS) and lipoprotein lipase (LPL), whereas lipolysis increased by activating phosphorylation of hormone-sensitive lipase (p-HSL) and AMP-activated protein kinase (p-AMPK). The extract inhibited adipocyte differentiation of 3T3-L1 preadipocytes through down-regulating adipogenic transcription factors, including peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1). This is attributed to the triggering of Wnt/β-catenin signaling. In addition, this study found that treatment with the extract activated HO-1 expression. Pharmacological approaches revealed that treatment with Zinc Protoporphyrin (ZnPP), an HO-1 inhibitor, resulted in an increase in lipid accumulation and a decrease in free glycerol levels. Finally, three adipogenic transcription factors, such as PPARγ, C/EBPα, and SREBP1, restored their expression in the presence of ZnPP. Analysis of chemical constituents revealed that the extract of D. divaricata is rich in 1,4-benzenediol, 7-tetradecenal, fucosterol, and n-hexadecanoic acid, which are known to have multiple pharmacological properties.

Positive Impacts of Aphanizomenon Flos Aquae Extract on Obesity-Related Dysmetabolism in Mice with Diet-Induced Obesity

The present study evaluated the ability of KlamExtra®, an Aphanizomenon flos aquae (AFA) extract, to counteract metabolic dysfunctions due to a high fat diet (HFD) or to accelerate their reversion induced by switching an HFD to a normocaloric diet in mice with diet-induced obesity. A group of HFD mice was fed with an HFD supplemented with AFA (HFD-AFA) and another one was fed with regular chow (standard diet-STD) alone or supplemented with AFA (STD-AFA). AFA was able to significantly reduce body weight, hypertriglyceridemia, liver fat accumulation and adipocyte size in HFD mice. AFA also reduced hyperglycaemia, insulinaemia, HOMA-IR and ameliorated the glucose tolerance and the insulin response of obese mice. Furthermore, in obese mice AFA normalised the gene and the protein expression of factors involved in lipid metabolism (FAS, PPAR-γ, SREBP-1c and FAT-P mRNA), inflammation (TNF-α and IL-6 mRNA, NFkB and IL-10 proteins) and oxidative stress (ROS levels and SOD activity). Interestingly, AFA accelerated the STD-induced reversion of glucose dysmetabolism, hepatic and VAT inflammation and oxidative stress. In conclusion, AFA supplementation prevents HFD-induced dysmetabolism and accelerates the STD-dependent recovery of glucose dysmetabolism by positively modulating oxidative stress, inflammation and the expression of the genes linked to lipid metabolism.

The complete sequence of the mitochondrial DNA and phylogenetic analysis of the marine red alga Grateloupia elliptica (Rhodophyta: Halymeniales)

Grateloupia elliptica (Holmes, 1896) is a red alga belonging to the order Halymeniales and phylum Rhodophyta. In this study, the complete mitochondrial DNA (mtDNA) of G. elliptica has been described. The complete circular mtDNA of G. elliptica was 28,503 bp in length, with an A + T content of 68.78%; it encoded a total of 49 genes, including 20 tRNA, three rRNA, and 26 protein-coding (CDS) genes. Phylogenetic analysis based on complete mitochondrial genomes revealed that G. elliptica was most closely related to G. angusta. The complete mitochondrial sequence of G. elliptica will enrich the mitochondrial genome database and provide useful resources for population genetics and evolution analyses.

Red seaweed extracts reduce methane production by altering rumen fermentation and microbial composition in vitro

A series of in vitro batch culture incubations were carried out to investigate changes in rumen fermentation characteristics, methane (CH4) production, and microbial composition in response to supplementation with five different red seaweed species (Amphiroa anceps, AANC; Asparagopsis taxiformis, ATAX; Chondracanthus tenellus, CTEN; Grateloupia elliptica, GELL; and Gracilaria parvispora, GPAR). Prior to the incubations, the total flavonoid and polyphenol content of the red seaweed extracts was quantified. The incubated substrate consisted of timothy hay and corn grain [60:40 dry matter (DM) basis]. Treatments were substrate mixtures without seaweed extract (CON) or substrate mixtures supplemented with 0.25 mg/mL of red seaweed extract. Samples were incubated for 6, 12, 24, 36, and 48 h. Each sample was incubated in triplicates in three separate runs. In vitro DM degradability, fermentation parameters (i.e., pH, volatile fatty acids, and ammonia nitrogen), total gas production, and CH4 production were analyzed for all time points. Microbial composition was analyzed using 16S rRNA amplicon sequencing after 24 h of incubation. The highest CH4 reduction (mL/g DM, mL/g digested DM, and % of total gas production) was observed in ATAX (51.3, 50.1, and 51.5%, respectively, compared to CON; P < 0.001) after 12 h of incubation. The other red seaweed extracts reduced the CH4 production (mL/g DM; P < 0.001) in the range of 4.6-35.0% compared to CON after 24 h of incubation. After 24 h of incubation, supplementation with red seaweed extracts tended to increase the molar proportion of propionate (P = 0.057) and decreased the acetate to propionate ratio (P = 0.033) compared to the CON. Abundances of the genus Methanobrevibacter and total methanogens were reduced (P = 0.050 and P = 0.016) by red seaweed extract supplementation. The linear discriminant analysis effect size (P < 0.05, LDA ≥ 2.0) showed that UG Succinivibrionaceae, Anaeroplasma, and UG Ruminococcaceae, which are associated with higher propionate production, starch degradation, and amylase activity were relatively more abundant in red seaweed extracts than in the CON. Our results suggest that supplementation with red seaweed extracts altered the microbiota, leading to the acceleration of propionate production and reduction in CH4 production.

Pheophorbide A isolated from Gelidium amansii inhibits adipogenesis by regulating adipogenic transcription factors and AMPK in 3T3-L1 adipocytes

Adipocyte lipid accumulation causes adipocyte hypertrophy and adipose tissue increment, leading to obesity. As part of our efforts to isolate antiobesity agents from natural products, we first isolated the active compound from the extract of Gelidium amansii through bioassay-guided fractionation. We then hypothesized that pheophorbide A isolated from G amansii inhibits adipogenesis by downregulating adipogenic transcription factors; therefore, the antiadipogenic effects of pheophorbide A were investigated in 3T3-L1 adipocytes. On differentiation of 3T3-L1 preadipocytes into adipocytes, they were treated with pheophorbide A (0-83 µM). Pheophorbide A inhibited triglyceride accumulation (half maximal inhibitory concentration = 114.2 µM) and stimulated glycerol release in a dose-dependent manner in 3T3-L1 adipocytes. In addition, pheophorbide A significantly decreased leptin concentrations in 3T3-L1 adipocytes. Pheophorbide A inhibited adipogenesis by suppressing the expression of adipogenic transcriptional factors including peroxisome proliferator-activated receptor γ, CCATT/enhancer binding protein α, sterol regulatory element binding protein 1c, and fatty acid synthase. It also induced the expression of phosphorylation of AMP-activated protein kinase. Therefore, these results suggest that pheophorbide A may be useful for preventing or treating obesity because of its inhibitory effect on adipogenesis.

Efficiency of Coriandrum sativum (Linn.) and Petroselinum crispum (Mill.) in Enhancing Iron Absorption: An In Silico and In Vitro Approach

Coriandrum sativum (Linn.) and Petroselinum crispum (Mill.) are the common herbs used for culinary purposes in daily life. The chlorophyll pigment in plants is being identified with various medicinal values, whereas iron is an essential micronutrient for the proper metabolism of the human body. The current research has been aimed at predicting the role of C. sativum and P. crispum in enhancing iron absorption via an in vitro approach. C. sativum and P. crispum have been analyzed for their capability of being a source of chlorophyll and iron concentration. The extracts prepared from solvents like carbinol, petroleum ether, and water were subjected to the identification of phytoconstituents through gas chromatography-mass spectrometry analysis, and the identified compounds were subjected to in silico studies against the iron-binding receptor, transferrin, to depict the binding affinity of the identified compounds. The carbinol extract was then put through in vitro analytical studies in Caco2 cell lines with a concentration of 500 µg/ml. Current research has shown that the leaves of C. sativum and P. crispum are an excellent source of chlorophyll and iron and has also suggested that these herbs efficiently enhance the absorption of iron in human intestinal cells.

Dietary fucoidan from a brown marine algae (Ecklonia cava) attenuates lipid accumulation in differentiated 3T3-L1 cells and alleviates high-fat diet-induced obesity in mice

Fucoidan from marine algae is used as a functional ingredient in the food. Here, we purified fucoidan fractions from a crude polysaccharide obtained after the crude polysaccharide of celluclast-assisted hydrolysate from Ecklonia cava (ECC). We evaluated the effect of ECC on lipid accumulation in differentiated 3T3-L1 adipocytes and investigated its anti-obesity effects in vivo in high-fat diet (HFD)-induced obese mice. In vitro Oil Red O staining revealed that treatment with ECC and its purified fucoidan fractions of celluclast assisted hydrolysate from Ecklonia cava (ECFs) remarkably reduced lipid accumulation in 3T3-L1 cells. ECF3 contained the highest contents of polysaccharides and sulfate compared with other fucoidan fractions. ECF3 treatment significantly reduced lipid accumulation in 3T3-L1 cells. Oral administration of ECC significantly reduced body weight, body weight gain, serum lipid content, and total white adipose tissue mass. Histological analysis revealed that ECC reduced lipid accumulation in EAT and liver tissues. Our findings suggest that the anti-obesity effects of ECC are associated with suppressing lipid accumulation in white adipose tissues and increased energy expenditure by upregulating the expression of thermogenic UCP1 and UCP3 in BAT. These results indicate that ECC and its ECFs possess anti-obesity properties and can be used in food and nutraceutical industries.

Verification of hotspots of genetic diversity in Korean population of Grateloupia asiatica and G. jejuensis (Rhodophyta) show low genetic diversity and similar geographic distribution

BACKGROUND

Understanding the genetic diversity and distribution patterns of seaweeds species is crucial for evaluating key regions of high genetic diversity. Identifying hotspots of high intraspecific diversity is an important step for developing conservation strategies. Grateloupia is a diverse genus of Rhodophyta, many of which are resource of numerous useful bioactive compounds; therefore, the genus is valuable target for conservation.

OBJECTIVE

The aim of this study is to examine the genetic diversity and population structure of two Grateloupia species, Grateloupia asiatica and Grateloupia jejuensis, with the understanding of the phylogeography of the Korean genetic diversity hotspot for two species.

METHODS

Plastid rbcL gene sequences of 134 specimens of G. asiatica and 112 specimens of G. jejuensis collected from the Korean coast were analyzed. We evaluated the number of haplotypes, genetic diversity (haplotype and nucleotide diversity), and haplotype networks of two species. Historical demographic was inferred by calculating neutrality tests and genetic differentiation was estimated using the fixation index, F_ST.

RESULTS

Our results show that both species are generally similar in geographical distribution patterns, that is, relatively homogeneous with few haplotypes derived from the most frequent haplotype. The east coast of Korea is identified as a 'hotspot' with the highest genetic diversity for both species, whereas Jeju Island is identified as a 'cold spot' with the lowest genetic diversity for G. jejuensis. Analyses across most distribution ranges of the two species in Korea reveal low genetic and haplotype diversities, which could indicate that these two Grateloupia species have either experienced a historical lack of diversity or a recent reduction in diversity due to high gene flow.

CONCLUSIONS

The low genetic diversity values found in the present study raise considerable concern about the conservation status of these two Grateloupia species and highlight the need to locate further hotspots of genetic diversity to strengthen their resilience against further decline.

Plant Extracts in Obesity: A Role of Gut Microbiota

Obesity has become one of the most serious chronic diseases threatening human health. Its occurrence and development are closely associated with gut microbiota since the disorders of gut microbiota can promote endotoxin production and induce inflammatory response. Recently, numerous plant extracts have been proven to mitigate lipid dysmetabolism and obesity syndrome by regulating the abundance and composition of gut microbiota. In this review, we summarize the potential roles of different plant extracts including mulberry leaf extract, policosanol, cortex moutan, green tea, honokiol, and capsaicin in regulating obesity via gut microbiota. Based on the current findings, plant extracts may be promising agents for the prevention and treatment of obesity and its related metabolic diseases, and the mechanisms might be associated with gut microbiota.

Polar Lipids Composition, Antioxidant and Anti-Inflammatory Activities of the Atlantic Red Seaweed Grateloupia turuturu

Grateloupia turuturu Yamada, 1941, is a red seaweed widely used for food in Japan and Korea which was recorded on the Atlantic Coast of Europe about twenty years ago. This seaweed presents eicosapentaenoic acid (EPA) and other polyunsaturated fatty acids (PUFAs) in its lipid fraction, a feature that sparked the interest on its potential applications. In seaweeds, PUFAs are mostly esterified to polar lipids, emerging as healthy phytochemicals. However, to date, these biomolecules are still unknown for G. turuturu. The present work aimed to identify the polar lipid profile of G. turuturu, using modern lipidomics approaches based on high performance liquid chromatography coupled to high resolution mass spectrometry (LC-MS) and gas chromatography coupled to mass spectrometry (GC-MS). The health benefits of polar lipids were identified by health lipid indices and the assessment of antioxidant and anti-inflammatory activities. The polar lipids profile identified from G. turuturu included 205 lipid species distributed over glycolipids, phospholipids, betaine lipids and phosphosphingolipids, which featured a high number of lipid species with EPA and PUFAs. The nutritional value of G. turuturu has been shown by its protein content, fatty acyl composition and health lipid indices, thus confirming G. turuturu as an alternative source of protein and lipids. Some of the lipid species assigned were associated to biological activity, as polar lipid extracts showed antioxidant activity evidenced by free radical scavenging potential for the 2,2'-azino-bis-3-ethyl benzothiazoline-6-sulfonic acid (ABTS^●+) radical (IC₅₀ ca. 130.4 μg mL^-1) and for the 2,2-diphenyl-1-picrylhydrazyl (DPPH^●) radical (IC₂₅ ca. 129.1 μg mL^-1) and anti-inflammatory activity by inhibition of the COX-2 enzyme (IC₅₀ ca. 33 µg mL^-1). Both antioxidant and anti-inflammatory activities were detected using a low concentration of extracts. This integrative approach contributes to increase the knowledge of G. turuturu as a species capable of providing nutrients and bioactive molecules with potential applications in the nutraceutical, pharmaceutical and cosmeceutical industries.