Colon cancer inhibitory properties of Caulerpa lentillifera polysaccharide and its molecular mechanisms based on three-dimensional cell culture model.

Caulerpa lentillifera is rich in polysaccharides, and its polysaccharides show a significant effect in different biological activities including anti-cancer activity. As an edible algae-derived polysaccharide, exploring the role of colon cancer can better develop the application from a dietary therapy perspective. However, more in-depth studies of C. lentillifera polysaccharide on anti-colon cancer activity and mechanism are needed. In this study, we found that Caulerpa lentillifera polysaccharides (CLP) showed potential anti-colon cancer effect on human colon cancer cell HT29 in monolayer (IC50 = 1.954 mg/mL) and spheroid (IC50 = 0.402 mg/mL). Transcriptomics and metabolomics analyses revealed that CLP had an inhibitory effect on HT29 3D spheroid cells by activating aminoacyl-tRNA biosynthesis as well as arginine and proline metabolism pathways. Furthermore, the anti-colon cancer effects of CLP were confirmed through other human colon cancer cell HCT116 and LoVo in monolayer cells (IC50 = 1.890 mg/mL and 1.437 mg/mL, respectively) and 3D spheroid cells (IC50 = 0.344 mg/mL and 0.975 mg/mL, respectively), and three patient-derived organoids with IC50 values of 6.333-8.780 mg/mL. This study provided basic data for the potential application of CLP in adjuvant therapeutic food for colon cancer on multiple levels, while further investigation of detailed mechanism in vivo was still required.

Pro-Apoptotic Activity and Cell Cycle Arrest of Caulerpa sertularioides against SKLU-1 Cancer Cell in 2D and 3D Cultures.

Cancer is a disease with the highest mortality and morbidity rate worldwide. First-line drugs induce several side effects that drastically reduce the quality of life of people with this disease. Finding molecules to prevent it or generate less aggressiveness or no side effects is significant to counteract this problem. Therefore, this work searched for bioactive compounds of marine macroalgae as an alternative treatment. An 80% ethanol extract of dried Caulerpa sertularioides (CSE) was analyzed by HPLS-MS to identify the chemical components. CSE was utilized through a comparative 2D versus 3D culture model. Cisplatin (Cis) was used as a standard drug. The effects on cell viability, apoptosis, cell cycle, and tumor invasion were evaluated. The IC50 of CSE for the 2D model was 80.28 µg/mL versus 530 µg/mL for the 3D model after 24 h of treatment exposure. These results confirmed that the 3D model is more resistant to treatments and complex than the 2D model. CSE generated a loss of mitochondrial membrane potential, induced apoptosis by extrinsic and intrinsic pathways, upregulated caspases-3 and -7, and significantly decreased tumor invasion of a 3D SKLU-1 lung adenocarcinoma cell line. CSE generates biochemical and morphological changes in the plasma membrane and causes cell cycle arrest at the S and G2/M phases. These findings conclude that C. sertularioides is a potential candidate for alternative treatment against lung cancer. This work reinforced the use of complex models for drug screening and suggested using CSE's primary component, caulerpin, to determine its effect and mechanism of action on SKLU-1 in the future. A multi-approach with molecular and histological analysis and combination with first-line drugs must be included.

Ulvophyte Green Algae Caulerpa lentillifera: Metabolites Profile and Antioxidant, Anticancer, Anti-Obesity, and In Vitro Cytotoxicity Properties.

Marine algae have excellent bioresource properties with potential nutritional and bioactive therapeutic benefits, but studies regarding Caulerpa lentillifera are limited. This study aims to explore the metabolites profile and the antioxidant, anticancer, anti-obesity, and in vitro cytotoxicity properties of fractionated ethanolic extract of C. lentillifera using two maceration and soxhlet extraction methods. Dried simplicia of C. lentillifera was mashed and extracted in ethanol solvent, concentrated and evaporated, then sequentially partitioned with equal volumes of ethyl acetate and n-Hexane. Six samples were used in this study, consisting of ME (Maceration-Ethanol), MEA (Maceration-Ethyl Acetate), MH (Maceration-n-Hexane), SE (Soxhletation-Ethanol), SEA (Soxhletation-Ethyl Acetate), and SH (Soxhletation-n-Hexane). Non-targeted metabolomic profiling was determined using LC-HRMS, while antioxidant, anti-obesity, and anticancer cytotoxicity were determined using DPPH and ABTS, lipase inhibition, and MTT assay, respectively. This study demonstrates that C. lentillifera has several functional metabolites, antioxidant capacity (EC50 MH is very close to EC50 of Trolox), as well as anti-obesity properties (EC50 MH < EC50 orlistat, an inhibitor of lipid hydrolyzing enzymes), which are useful as precursors for new therapeutic approaches in improving obesity-related diseases. More interestingly, ME, MH, and SE are novel bioresource agents for anticancer drugs, especially for hepatoma, breast, colorectal, and leukemia cancers. Finally, C. lentillifera can be a nutraceutical with great therapeutic benefits.

An Efficient and Quick Analytical Method for the Quantification of an Algal Alkaloid Caulerpin Showed In-Vitro Anticancer Activity against Colorectal Cancer.

Biological invasion is the successful spread and establishment of a species in a novel environment that adversely affects the biodiversity, ecology, and economy. Both invasive and non-invasive species of the Caulerpa genus secrete more than thirty different secondary metabolites. Caulerpin is one of the most common secondary metabolites in genus Caulerpa. In this study, caulerpin found in invasive Caulerpa cylindracea and non-invasive Caulerpa lentillifera extracts were analyzed, quantified, and compared using high-performance thin layer chromatography (HPTLC) for the first time. The anticancer activities of caulerpin against HCT-116 and HT-29 colorectal cancer (CRC) cell lines were also tested. Caulerpin levels were found higher in the invasive form (108.83 ± 5.07 µg mL-1 and 96.49 ± 4.54 µg mL-1). Furthermore, caulerpin isolated from invasive Caulerpa decreased cell viability in a concentration-dependent manner (IC50 values were found between 119 and 179 µM), inhibited invasion-migration, and induced apoptosis in CRC cells. In comparison, no cytotoxic effects on the normal cell lines (HDF and NIH-3T3) were observed. In conclusion, HPTLC is a quick and novel method to investigate the caulerpin levels found in Caulerpa extracts, and this paper proposes an alternative utilization method for invasive C. cylindracea due to significant caulerpin content compared to non-invasive C. lentillifera.

Phytochemical Analysis and Molecular Identification of Green Macroalgae Caulerpa spp. from Bali, Indonesia.

The studies of the Bulung Boni and Bulung Anggur (Caulerpa spp.) species and secondary metabolites are still very limited. Proper identification will support various aspects, such as cultivation, utilization, and economic interests. Moreover, understanding the secondary metabolites will assist in developing algae-based products. This study aimed to identify these indigenous Caulerpa algae and analyze their bioactive components. The tufA sequence was employed as a molecular marker in DNA barcoding, and its bioactive components were identified using the GC-MS method. The phylogenetic tree was generated in MEGA 11 using the maximum likelihood method, and the robustness of the tree was evaluated using bootstrapping with 1000 replicates. This study revealed that Bulung Boni is strongly connected to Caulerpa cylindracea. However, Bulung Anggur shows no close relationship to other Caulerpa species. GC-MS analysis of ethanolic extracts of Bulung Boni and Bulung Anggur showed the presence of 11 and 13 compounds, respectively. The majority of the compounds found in these algae have been shown to possess biological properties, such as antioxidant, antibacterial, anticancer, anti-inflammation, and antidiabetic. Further study is necessary to compare the data obtained using different molecular markers in DNA barcoding, and to elucidate other undisclosed compounds in these Caulerpa algae.

The Enhancing Immune Response and Anti-Inflammatory Effects of Caulerpa lentillifera Extract in RAW 264.7 Cells.

BACKGROUND: Caulerpa lentillifera (CL) is a green seaweed, and its edible part represents added value as a functional ingredient. CL was dried and extracted for the determination of its active compounds and the evaluation of its biological activities. The major constituents of CL extract (CLE), including tannic acid, catechin, rutin, and isoquercetin, exhibited beneficial effects, such as antioxidant activity, anti-diabetic activity, immunomodulatory effects, and anti-cancer activities in in vitro and in vivo models. Whether CLE has an anti-inflammatory effect and immune response remains unclear. METHODS: This study examined the effect of CLE on the inflammatory status and immune response of lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and the mechanisms involved therein. RAW264.7 cells were treated with different concentrations of CLE (0.1-1000 µg/mL) with or without LPS (1 µg/mL) for 24 h. Expression and production of the inflammatory cytokines, enzymes, and mediators were evaluated. RESULTS: CLE suppressed expression and production of the pro-inflammatory cytokines IL-6 and TNF-α. Moreover, CLE inhibited expression and secretion of the inflammatory enzyme COX-2 and the mediators PGE2 and NO. CLE also reduced DNA damage. Furthermore, CLE stimulated the immune response by modulating the cell cycle regulators p27, p53, cyclin D2, and cyclin E2. CONCLUSIONS: CLE inhibits inflammatory responses in LPS-activated macrophages by downregulating inflammatory cytokines and mediators. Furthermore, CLE has an immunomodulatory effect by modulating cell cycle regulators.

Immunomodulatory sulfated polysaccharides from Caulerpa racemosa var. peltata induces metabolic shifts in NF-κB signaling pathway in RAW 264.7 macrophages.

Algal polysaccharide activates macrophages to alter physiologic biomarkers to drive the immunomodulatory phenotype, but it lacks specific biomarkers involved in the biochemical underpinning process. Here, we undertook an extensive analysis of the RAW 264.7 macrophages induced by an immunostimulating sulfated polysaccharide from Caulerpa racemosa var. peltata (CRVP-1) employing combined transcriptomic, proteomic, and metabolomic analyses to reveal the molecular details occurring in the CRVP-1-induced immunomodulatory process. The omics profiling of CRVP-1-activated macrophage demonstrated a total of 8844 genes (4354 downregulated and 4490 upregulated), 1243 proteins (620 downregulated and 623 upregulated), and 68 metabolites (52 downregulated and16 upregulated). Further, the co-mapped correlation network of omics combined with Western blot and immunofluorescence staining indicated that the cluster of differentiation 14 (CD14) might assist Toll-like receptor 4 (TLR4) involved in nuclear factor kappa-B (NF-κB) signaling pathway to drive the immunomodulatory phenotype. Together, our results discover novel physiologic biomarkers in the immunomodulatory activities of algal polysaccharides.

In Vitro Antitumor Potential of Sulfated Polysaccharides from Seaweed Caulerpa cupressoides var. flabellata.

Seaweeds are important source of bioactive compounds, including sulfated polysaccharides (SP). Because of their structural heterogeneity, these compounds are promising sources of anticancer compounds. SP from brown and red seaweeds have shown antimelanoma activity in different in vitro and in vivo models. However, SP from green seaweed are still poorly evaluated. Therefore, SP were extracted from the green alga Caulerpa cupressoides var. flabellata, and their antiproliferative, anti-migratory, and inhibitory effect on melanin production on B16-F10 melanoma cells was evaluated. Cell assays, including flow cytometry, demonstrated that SP (100-1000 µg mL-1) are non-cytotoxic, do not induce apoptosis or necrosis, and do not interfere with cell cycle. However, SP (1000 µg mL-1) were found to significantly inhibit cell colony formation (80-90%), cell migration (40-75%), and melanin production (~ 20%). In summary, these results showed that SP inhibited important melanoma development events without cytotoxicity effects, suggesting that C. cupressoides may be an important source of SP with antitumor properties.

Anti-proliferative and ROS-inhibitory activities reveal the anticancer potential of Caulerpa species.

Seaweeds are considered a promising functional food and safe for human consumption as they have significant health benefits. Five abundant tropical seaweeds, Caulerpa racemosa var. macrophysa, Caulerpa scalpelliformis, Grateloupia indica, Sargassum linearifolium, and Spatoglossum asperum rich in metabolites, phenolic, and flavonoid compounds, were analyzed for the anti-proliferative and ROS inhibitory activities including transcript expression of cancer-linked key genes and apoptosis. C. racemosa var. macrophysa showed the maximum effective activities with a lower dose of extract, about 130 ± 30 and 23 ± 1 µg ml-1 EC50 dose for HeLa and Huh-7, respectively, followed by C. scalpelliformis, showing EC50 dose about 200 ± 10 and 140 ± 30 µg ml-1, respectively. Similarly, about 56% and 54% ROS inhibition were determined with Caulerpa spp. for HeLa and Huh-7 cells, respectively. Results indicated that tropical green seaweed Caulerpa spp. (C. racemosa var. macrophysa and C. scalpelliformis) have substantial potential of ROS inhibition. Further, it was observed that different cancer-linked marker proteins encoding genes were deferentially expressed with seaweed extracts in different cell lines. Overall, it is concluded that Caulerpa spp. are rich in antioxidant and anti-proliferative activities. Caulerpa spp. have potential to be explored further for cancer preventive properties or functional food or nutraceuticals applications.

Caulerpa okamurae extract attenuates inflammatory interaction, regulates glucose metabolism and increases insulin sensitivity in 3T3-L1 adipocytes and RAW 264.7 macrophages.

OBJECTIVE: To examine whether Caulerpa okamurae ethanolic extract (COE) could inhibit obesity-mediated inflammation, improve glucose metabolism and increase insulin sensitivity, using in vitro cell models of RAW 264.7 macrophages and 3T3-L1 adipocytes. METHODS: We cocultured 3T3-L1 adipocytes in direct contact with lipopolysaccharide-stimulated RAW 264.7 macrophages and induced insulin resistance in 3T3-L1 adipocytes with tumor necrosis factor-α (TNF-α) in the presence or absence of 250 µg/mL of COE. We investigated various markers of inflammation, glucose regulation and insulin sensitivity in these models using Griess reagent to measure nitric oxide (NO) production, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxyglucose to measure glucose uptake, Western blot analysis to quantify protein expression and reverse transcriptase-polymerase chain reaction to evaluate mRNA expression. RESULTS: We found that COE (250 µg/mL) significantly inhibited the lipopolysaccharide-induced inflammatory response in RAW 264.7 macrophages by downregulating NO production, nitric oxide synthase 2 expression and nuclear translocation of nuclear factor-κB. COE also showed similar anti-inflammatory activity in coculture, along with decreased TNF-α, interleukin-6 and monocyte chemoattractant protein mRNA expression. In addition, COE also improved glucose uptake in coculture by upregulating glucose transporter-4 (GLUT-4) and adiponectin and reducing serine phosphorylation of insulin receptor substrate-1 (IRS1). In the TNF-α-induced insulin resistance model of 3T3-L1 adipocytes, COE significantly improved both basal and insulin-stimulated glucose uptake, accompanied by phosphorylation of IRS1 at tyrosine 632, phospho-5' adenosine monophosphate-activated protein kinase α and glycogen synthase kinase-3ß (Ser9) as well as upregulation of GLUT-4. CONCLUSION: Together, these findings suggest that COE has potential to treat or prevent obesity-induced metabolic disorders.

Anti-inflammatory activity and structural identification of a sulfated polysaccharide CLGP4 from Caulerpa lentillifera.

In the present study, the in vitro anti-inflammatory activity of four purified polysaccharides (CLGP1, CLGP2, CLGP3 and CLGP4) extracted from edible green algae Caulerpa lentillifera was evaluated. As a result, CLGP4 exhibited more effectively inhibitory effect on LPS-induced HT29 cells, including reducing the production of IL-1ß, TNF-α, SIgA and mucin2, and decreasing the expression of IL-1ß and TNF-α. According to the results, CLGP4 showed a better anti-inflammatory effect, might highly related to the presence of sulfate groups. Furthermore, the structure of CLGP4 was analyzed by methylation analysis, GC-MS and NMR spectroscopy. It was found that CLGP4 was a novel xylogalactomanan consisting of ß-(1 â†’ 4)-Manp, →2,4)Manp(1→, ß-(1 â†’ 2)-Manp, ß-(1 â†’ 3)-Galp, ß-(1 â†’ 4)-Xylp, terminal ß-Galp and terminal ß-Xylp residues. Additionally, the sulfate groups were located on C-3 of â†’4)Xylp(1→, C-6 of â†’3)Galp(1→ and C-3 of â†’2)Manp(1→. These results could enlarge the potential application of CLGP4 as functional ingredient to attenuate inflammation.

Study on immunostimulatory activity and extraction process optimization of polysaccharides from Caulerpa lentillifera.

The process of extracting polysaccharides from the green algae Caulerpa lentillifera was studied by single factor experiments and response surface methodology. Additionally, the immunostimulatory activity of Caulerpa lentillifera polysaccharides (CLP) on RAW264.7 mouse macrophage was evaluated by in vitro cell experiments. The results showed that the optimal extraction conditions consisted of ultrasonification for 30 min, extraction time of 9 h, extraction temperature of 100 °C, and a ratio of water to raw material of 40:1. RAW264.7 macrophage exhibited enhanced phagocytosis with no toxic effects after treatment with CLP. In addition, CLP effectively increased the synthesis and secretion of cytokines (IL-6, TNF-α, IL-1ß, and NO), whereby the secretion levels of IL-6, TNF-α, and IL-1ß were 1,840.32 ± 21.03 pg/mL (50 µg/mL), 197.17 ± 3.13 ng/mL (50 µg/mL), and 1,178.35 ± 78.82 pg/mL (25 µg/mL), respectively. The polysaccharides contained in Caulerpa lentillifera have potential value for further development due to their immunological activity.

Caulerpa lentillifera polysaccharides enhance the immunostimulatory activity in immunosuppressed mice in correlation with modulating gut microbiota.

In this study, the immunostimulatory activity of Caulerpa lentillifera polysaccharides (CLP) was elucidated in cytoxan (CTX)-induced immunosuppressed BALB/c mice. The results showed that CLP ameliorated the CTX-evoked damage to body weight, colon length and thymus/spleen indexes and enhanced the secretions of interleukin (IL)-1ß, tumor necrosis factor (TNF)-α and superoxidase dismutase (SOD) in serum and thymic, splenic and colonic tissues of the immunosuppressed mice. Besides, CLP promoted the production of secretory immunoglobulin A (SIgA) and mucin2 in the colonic tissue of the immunosuppressed mice. Associated with the above immunostimulatory effects, CLP positively affected the production of short chain fatty acids (SCFAs) and microbiota diversity and composition, such as improvement in the growth of Lactobacillus, Coriobacteriaceae, Ruminococcaceae, Clostridium_XVIII and Helicobacter, whereas it suppressed the microbial populations of Bacteroides, Barnesiella and Lachnospiraceae. These findings suggested that CLP modulated SCFA production and gut microbiota in the immunosuppressed mice, evoking the colonic mucosal immunity, which might activate the systemic immunity in blood, thymus and spleen. The results could be helpful for understanding the functions of CLP, supporting their potential as novel prebiotics and immunostimulators.

Caulerpa Cupressoides Var. Flabellata.

Green seaweeds are rich sources of sulfated polysaccharides (SPs) with potential biomedical and nutraceutical applications. The aim of this work was to evaluate the immunostimulatory activity of SPs from the seaweed, Caulerpa cupressoides var. flabellata on murine RAW 264.7 macrophages. SPs were evaluated for their ability to modify cell viability and to stimulate the production of inflammatory mediators, such as nitric oxide (NO), intracellular reactive oxygen species (ROS), and cytokines. Additionally, their effect on inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) gene expression was investigated. The results showed that SPs were not cytotoxic and were able to increase in the production of NO, ROS and the cytokines, tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). It was also observed that treatment with SPs increased iNOS and COX-2 gene expression. Together, these results indicate that C. cupressoides var. flabellata SPs have strong immunostimulatory activity, with potential biomedical applications.

Marine Natural Product Bis-indole Alkaloid Caulerpin: Chemistry and Biology.

Marine bis-indole alkaloids comprise a large and increasingly growing class of secondary metabolites, and continue to deliver a great variety of structural templates for diverse biological targets. The alkaloids derived from marine resources play a crucial role in medicinal chemistry and as chemical agents. In particular, bis-indole alkaloid caulerpin which has been isolated from marine green algae Caulerpa and a red algae Chondria armata at various places around the world, was tested for several therapeutic potentials such as anti-diabetic, antinociceptive, anti-inflammatory, anti-tumor, anti- larvicidal, anti-herpes, anti-tubercular, anti-microbial and immunostimulating activities as well as a means of other chemical agents. Herein, we summarized the discovery and isolation of caulerpin, and its potential medicinal and chemical applications in chronological order with various aspects. Additionally, synthesis of caulerpin and its functional analogues have also been reviewed.

A lectin fraction from green seaweed Caulerpa cupressoides inhibits inflammatory nociception in the temporomandibular joint of rats dependent from peripheral mechanisms.

Temporomandibular disorders are the second most common cause of orofacial pain mediated by inflammatory compounds, which in many cases leads to chronic orofacial pain. This study assessed the antinociceptive and anti-inflammatory effects of a lectin from the green seaweed Caulerpa cupressoides (CcL) on hypernociception inflammatory in TMJ of rats and investigated the involvement of different mechanisms. Rats received i.v. CcL 30 min prior to injection of flogistic agentes or 0.9% saline into the left TMJ. Pretreatment with CcL (0. 1; 1 or 10 mg/kg) promoted a reduction (p < 0.05) of inflammatory hypernociception induced by 1.5% Formalin along with inhibition of inflammatory plasma extravasation, cytokines levels, ciclooxigenase-2, and intercellular adhesion molecule (ICAM-1). CcL was able to inhibit the nociceptive response induced by 1.5% Capsaicin, suggesting that CcL has an antinociceptive effect, acting directly on the primary nociceptive neurons. CcL also inhibited the nociceptive response induced by Carrageenan (100 µg/TMJ) or Serotonin (5-HT) (225 µg/TMJ). In conclusion, the results demonstrate that administration of CcL has a potential antinociceptive and anti-inflammatory effect, with a mechanism that is partially dependent on TNF-α, IL-1ß, COX-2 and ICAM-1 inhibition and independently from the cannabinoide and opioid system and NO/cGMP/PKG/K+ATP channel pathway.

Genotoxicity and osteogenic potential of sulfated polysaccharides from Caulerpa prolifera seaweed.

Marine algae are sources of novel bioactive molecules and present a great potential for biotechnological and biomedical applications. Although green algae are the least studied type of seaweed, several of their biological activities have already been described. Here, we investigated the osteogenic potential of Sulfated Polysaccharide (SP)-enriched samples extracted from the green seaweed Caulerpa prolifera on human mesenchymal stem cells isolated from Wharton jelly (hMSC-WJ). In addition, the potential genotoxicity of these SPs was determined by cytokinesis-block micronucleus (CBMN) assay. SP-enriched samples did not show significant cytotoxicity towards hMSCs-WJ at a concentration of up to 10µg/mL, and after 72h of exposure. SP enrichment also significantly increased alkaline phosphatase (ALP) activity, promoting calcium accumulation in the extracellular matrix. Among the SP-enriched samples, the CP0.5 subfraction (at 5µg/mL) presented the most promising results. In this sample, ALP activity was increased approximately by 60%, and calcium accumulation was approximately 6-fold above the negative control, indicating high osteogenic potential. This subfraction also proved to be non-genotoxic, according to the CBMN assay, as it did not induce micronuclei. The results of this study highlight, for the first time, the potential of these SPs for the development of new therapies for bone regeneration.

Purification, structural features and immunostimulatory activity of novel polysaccharides from Caulerpa lentillifera.

In this study, four purified fractions (CLGP1, CLGP2, CLGP3 and CLGP4) were prepared from green seaweed Caulerpa lentillifera. They were identified to be a novel kind of xylogalactomanans, differed in molecular weight, monosaccharide composition, and the content of uronic acids and sulfate groups, leading to various ζ-potential, ultrastructure and immunostimulatory activity. Especially, CLGP4 was quite different from the others, as it was found to be a homogeneous heteropolysaccharide composed of Xyl, Man and Gal in a percentage ratio of 1.00:2.15:2.40 with 3877.8kDa. Moreover, CLGP4 contained minor uronic acids (2.37%±0.94%) and the highest sulfate content (21.26%±1.22%). These differences in structural features had an effect on the ζ-potential and ultrastructure of CLGP4, showing rod-, rubble- and ellipsoid-shaped particles with largest negatively charge. In vitro immunostimulatory activity evaluation revealed that all the four fractions significantly stimulated macrophages, but CLGP4 showed more potent immunostimulatory activity due to its stronger function on promoting proliferation of macrophages, enhancing phagocytosis, NO production and acid phosphatase activity in macrophages. Therefore, CLGP4 could be explored as a natural immunomodulator. These results would help a fully exploition of Caulerpa lentillifera polysaccharides recognized as health-improving ingredients in functional foods.

Caulerpa lentillifera extract ameliorates insulin resistance and regulates glucose metabolism in C57BL/KsJ-db/db mice via PI3K/AKT signaling pathway in myocytes.

BACKGROUND: Glucose homeostasis is distorted by defects of the PI3K/AKT and AMPK pathways in insulin-sensitive tissues, allowing the accumulation of glucose in the blood. The purpose of this study was to assess the effects and mechanisms by which ethanol extract of Caulerpa lentillifera (CLE) regulates glucose metabolism in C57BL/KsJ-db/db (db/db) mice. METHODS: Mice were administered CLE (250 or 500 mg/kg BW) or rosiglitazone (RSG, 10 mg/kg BW) for 6 weeks. Then, oral glucose tolerance test (OGTT) and intraperitoneal insulin tolerance test (IPITT) were performed, and blood glucose was measured in db/db mice. Levels of insulin and insulin resistance factors in plasma, glycogen content in the liver, and IRS, PI3K, AKT, and GLUT4 expressions in skeletal muscles were measured in db/db mice. Glucose uptake and insulin signaling molecules were measured in L6 myocytes, using fluorometry and Western blotting. RESULTS: CLE significantly decreased fasting blood glucose, glucose level in OGTT and IPITT, plasma insulin, homeostatic model assessment-insulin resistant (HOMA-IR), TNF-α, IL-6, FFA, TG and TC levels, and hepatic glycogen content in db/db mice. CLE significantly increased the activation of IRS, AKT, PI3K, and GLUT4, which are the key effector molecules of the PI3K/AKT pathway in L6 myocytes and the skeletal muscles of db/db mice. The enhanced glucose uptake by CLE was abolished by treatment with a PI3K inhibitor (LY294002), but not by an AMPK inhibitor (compound C) in L6 myocytes. CLE regulated glucose uptake and homeostasis via the PI3K/AKT pathway in myocytes and db/db mice, respectively. CONCLUSION: Our results suggest that CLE could be a potential candidate for the prevention of diabetes.

Bioactive constituents from the green alga Caulerpa racemosa.

Three diterpenoids, including a pair of epimers, racemobutenolids A and B (1 and 2), and 4',5'-dehydrodiodictyonema A (3), an α-tocopheroid, α-tocoxylenoxy (8), and an 28-oxostigmastane steroid, (23E)-3ß-hydroxy-stigmasta-5,23-dien-28-one (11), together with 12 known compounds, were isolated from the green alga Caulerpa racemosa. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data, and by comparison with data for related known compounds. The epimers (1 and 2) are two unusual diterpenoid lactones bearing a ß-methyl-γ-substituted butenolide moiety, and 3 and 8 represent the first naturally occurring natural products with a hematinic acid ester group and 3,5-dimethylphenoxy functionality, respectively. The enzyme inhibitory activities of the isolated compounds were evaluated in vitro against PTP1B and related PTPs (TCPTP, CDC25B, LAR, SHP-1, and SHP-2). Compounds 3, 5, 6, and 9-14 exhibited different levels of PTP1B inhibitory activities with IC50 values ranging from 2.30 to 50.02µM. Of these compounds, 3, 9, and 11 showed the most potent inhibitory activities towards PTP1B with IC50 values of 2.30, 3.85, and 3.80µM, respectively. More importantly, the potent PTP1B inhibitors 3, 9, and 11 also displayed high selectivity over the highly homologous TCPTP and other PTPs. Also, the neuroprotective effects of the isolates against Aß25-35-induced cell damage in SH-SY5Y cells were investigated. Compounds 10, 11, and 14 exhibited significant neuroprotective effects against Aß25-35-induced SH-SY5Y cell damage with 11.31-15.98% increases in cell viability at 10µM. In addition, the cytotoxic activities of the isolated compounds were tested against the human cancer cell lines A-549 and HL-60.