3-Hydroxy-4,7-megastigmadien-9-one, isolated from Ulva pertusa, attenuates TLR9-mediated inflammatory response by down-regulating mitogen-activated protein kinase and NF-κB pathways

Anti-inflammatory potential of ulvan

Green seaweeds are a widespread group of marine macroalgae that could be regarded as biorenewable source of valuable compounds, in particular sulfated polysaccharides like ulvans with interesting biological properties. Among them, anti-inflammatory activity represents an interesting target, since ulvans could potentially avoid side effects of conventional therapies. However, a great variability in ulvan content, composition, structure and properties occurs depending on seaweed specie and growth and processing conditions. All these aspects should be carefully considered in order to have reproducible and well characterized products. This review presents some concise ideas on ulvan composition and general concepts on inflammation mechanisms. Then, the main focus is on the importance of adequate selection of extraction, depolymerization and purification technologies followed by an updated survey on anti-inflammatory properties of ulvans through modulation of different signaling pathways. The potential application in a number of diseases, with special emphasis on inflammaging, gut microbiota dysbiosis, wound repair, and metabolic diseases is also discussed. This multidisciplinary overview tries to present the potential of ulvans considering not only mechanistic, but also processing and applications aspects, trusting that it can aid in the development and application of this widely available and renewable resource as an efficient and versatile anti-inflammatory agent.

Anti-Inflammatory Effects of Bioactive Compounds from Seaweeds, Bryozoans, Jellyfish, Shellfish and Peanut Worms

Inflammation is a defense mechanism of the body in response to harmful stimuli such as pathogens, damaged cells, toxic compounds or radiation. However, chronic inflammation plays an important role in the pathogenesis of a variety of diseases. Multiple anti-inflammatory drugs are currently available for the treatment of inflammation, but all exhibit less efficacy. This drives the search for new anti-inflammatory compounds focusing on natural resources. Marine organisms produce a broad spectrum of bioactive compounds with anti-inflammatory activities. Several are considered as lead compounds for development into drugs. Anti-inflammatory compounds have been extracted from algae, corals, seaweeds and other marine organisms. We previously reviewed anti-inflammatory compounds, as well as crude extracts isolated from echinoderms such as sea cucumbers, sea urchins and starfish. In the present review, we evaluate the anti-inflammatory effects of compounds from other marine organisms, including macroalgae (seaweeds), marine angiosperms (seagrasses), medusozoa (jellyfish), bryozoans (moss animals), mollusks (shellfish) and peanut worms. We also present a review of the molecular mechanisms of the anti-inflammatory activity of these compounds. Our objective in this review is to provide an overview of the current state of research on anti-inflammatory compounds from marine sources and the prospects for their translation into novel anti-inflammatory drugs.

Microalgae, Seaweeds and Aquatic Bacteria, Archaea, and Yeasts: Sources of Carotenoids with Potential Antioxidant and Anti-Inflammatory Health-Promoting Actions in the Sustainability Era

Carotenoids are a large group of health-promoting compounds used in many industrial sectors, such as foods, feeds, pharmaceuticals, cosmetics, nutraceuticals, and colorants. Considering the global population growth and environmental challenges, it is essential to find new sustainable sources of carotenoids beyond those obtained from agriculture. This review focuses on the potential use of marine archaea, bacteria, algae, and yeast as biological factories of carotenoids. A wide variety of carotenoids, including novel ones, were identified in these organisms. The role of carotenoids in marine organisms and their potential health-promoting actions have also been discussed. Marine organisms have a great capacity to synthesize a wide variety of carotenoids, which can be obtained in a renewable manner without depleting natural resources. Thus, it is concluded that they represent a key sustainable source of carotenoids that could help Europe achieve its Green Deal and Recovery Plan. Additionally, the lack of standards, clinical studies, and toxicity analysis reduces the use of marine organisms as sources of traditional and novel carotenoids. Therefore, further research on the processing of marine organisms, the biosynthetic pathways, extraction procedures, and examination of their content is needed to increase carotenoid productivity, document their safety, and decrease costs for their industrial implementation.

Moutan Cortex Extract Modulates Macrophage Activation via Lipopolysaccharide-Induced Calcium Signaling and ER Stress-CHOP Pathway

Moutan Cortex, Paeonia suffruticosa root, has long been used as a medicine for the treatment of inflammatory diseases. The aim of this study was to evaluate the modulative properties of Moutan Cortex water extract (CP) on endoplasmic reticulum (ER) stress-related macrophage activation via the calcium-CHOP pathway. RAW 264.7 mouse macrophages were activated by lipopolysaccharide (LPS), and the levels of various inflammatory mediators from RAW 264.7 were evaluated. The multiplex cytokine assay was used to investigate both cytokines and growth factors, and RT-PCR was used to investigate the expressions of inflammation-related genes, such as CHOP. Data represent the levels of NO and cytosolic calcium in LPS-stimulated RAW 264.7 were significantly inhibited by CP as well as hydrogen peroxide (p < 0.05). Minutely, NO production in LPS-stimulated RAW 264.7 incubated with CP at concentrations of 25, 50, 100, and 200 µg/mL for 24 h was 97.32 ± 1.55%, 95.86 ± 2.26%, 94.64 ± 1.83%, and 92.69 ± 2.31% of the control value (LPS only), respectively (p < 0.05). Calcium release in LPS-stimulated RAW 264.7 incubated with CP at concentrations of 25, 50, 100, and 200 µg/mL for 18 h was 95.78 ± 1.64%, 95.41 ± 1.14%, 94.54 ± 2.76%, and 90.89 ± 3.34% of the control value, respectively (p < 0.05). Hydrogen peroxide production in LPS-stimulated RAW 264.7 incubated with CP at concentrations of 25, 50, 100, and 200 µg/mL for 24 h was 79.15 ± 7.16%, 63.83 ± 4.03%, 46.27 ± 4.38%, and 40.66 ± 4.03% of the control value, respectively (p < 0.05). It is interesting that the production of IL-6, TNF-α, G-CSF, MIP-1α, MIP-2, and M-CSF in LPS-stimulated RAW 264.7 were significantly inhibited by CP (p < 0.05), while the production of LIX, LIF, RANTES, and MIP-1β showed a meaningful decrease. CP at concentrations of 25, 50, 100, and 200 µg/mL significantly reduced the transcription of Chop, Camk2α, NOS, STAT1, STAT3, Ptgs2, Jak2, c-Jun, Fas, c-Fos, TLR3, and TLR9 in LPS-stimulated RAW 264.7 (p < 0.05). CP at concentrations of 25, 50, and 100 µg/mL significantly reduced the phosphorylation of STAT3, p38 MAPK, and IκB-α in LPS-stimulated RAW 264.7 (p < 0.05). These results suggest that CP might modulate macrophage activation via LPS-induced calcium signaling and the ER stress-CHOP pathway.

Nutraceutical potentials of algal ulvan for healthy aging

Several theories for aging are constantly put forth to explain the underlying mechanisms. Oxidative stress, DNA dysfunction, inflammation, and mitochondrial dysfunction, along with the release of cytochrome c are some of these theories. Diseases such as type 2 diabetes mellitus, intestinal dysfunction, cardiovascular diseases, hepatic injury, and even cancer develop with age and eventually cause death. Ulva polysaccharides, owing to their special structures and various functions, have emerged as desirable materials for keeping healthy. These polysaccharide structures are found to be closely related to the extraction methods, seaweed strains, and culture conditions. Ulvan is a promising bioactive substance, a potential functional food, which can regulate immune cells to augment inflammation, control the activity of aging-related genes, promote tumor senescence, enhance mitochondrial function, maintain liver balance, and protect the gut microbiome from inflammatory attacks. Given the desirable physiochemical and gelling properties of ulvan, it would serve to improve the quality and shelf-life of food.

Inhibitory Effects of Cucurbitane-Type Triterpenoids from Momordica charantia Fruit on Lipopolysaccharide-Stimulated Pro-Inflammatory Cytokine Production in Bone Marrow-Derived Dendritic Cells

The bitter melon, Momordica charantia L., was once an important food and medicinal herb. Various studies have focused on the potential treatment of stomach disease with M. charantia and on its anti-diabetic properties. However, very little is known about the specific compounds responsible for its anti-inflammatory activities. In addition, the in vitro inhibitory effect of M. charantia on pro-inflammatory cytokine production by lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) has not been reported. Phytochemical investigation of M. charantia fruit led to the isolation of 15 compounds (1-15). Their chemical structures were elucidated spectroscopically (one- and two-dimensional nuclear magnetic resonance) and with electrospray ionization mass spectrometry. The anti-inflammatory effects of the isolated compounds were evaluated by measuring the production of the pro-inflammatory cytokines interleukin IL-6, IL-12 p40, and tumor necrosis factor α (TNF-α) in LPS-stimulated BMDCs. The cucurbitanes were potent inhibitors of the cytokines TNF-α, IL-6, and IL-12 p40, indicating promising anti-inflammatory effects. Based on these studies and in silico simulations, we determined that the ligand likely docked in the receptors. These results suggest that cucurbitanes from M. charantia are potential candidates for treating inflammatory diseases.

Bioactive Compounds from Polygala tenuifolia and Their Inhibitory Effects on Lipopolysaccharide-Stimulated Pro-inflammatory Cytokine Production in Bone Marrow-Derived Dendritic Cells

The roots of Polygala tenuifolia Wild (Polygalaceae), which is among the most important components of traditional Chinese herbal medicine, have been widely used for over 1000 years to treat a variety of diseases. In the current investigation of secondary metabolites with anti-inflammatory properties from Korean medicinal plants, a phytochemical constituent study led to the isolation of 15 compounds (1–15) from the roots of P. tenuifolia via a combination of chromatographic methods. Their structures were determined by means of spectroscopic data such as nuclear magnetic resonance (NMR), 1D- and 2D-NMR, and liquid chromatography-mass spectrometry (LC-MS). As the obtained results, the isolated compounds were divided into two groups—phenolic glycosides (1–9) and triterpenoid saponins (10–15). The anti-inflammatory effects of crude extracts, fractions, and isolated compounds were investigated on the production of the pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumour necrosis factor-α in lipopolysaccharide-stimulated bone marrow-derived dendritic cells. The IC₅₀ values, ranging from 0.08 ± 0.01 to 21.05 ± 0.40 μM, indicated potent inhibitory effects of the isolated compounds on the production of all three pro-inflammatory cytokines. In particular, compounds 3–12, 14, and 15 showed promising anti-inflammatory activity. These results suggest that phenolic and triterpenoid saponins from P. tenuifolia may be excellent anti-inflammatory agents.

Marine natural products

Covering: January to December 2017This review covers the literature published in 2017 for marine natural products (MNPs), with 740 citations (723 for the period January to December 2017) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 477 papers for 2017), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Geographic distributions of MNPs at a phylogenetic level are reported.

Sterols from the Green Alga Ulva australis

Three new sterols, (24R)-5,28-stigmastadiene-3β,24-diol-7-one (1), (24S)-5,28-stigmastadiene-3β,24-diol-7-one (2), and 24R and 24S-vinylcholesta-3β,5α,6β,24-tetraol (3), together with three known sterols (4–6) were isolated from the green alga Ulva australis. The structures of the new compounds (1–3) were elucidated through 1D and 2D nuclear magnetic resonance spectroscopy as well as mass spectrometry. Compounds 4–6 were identified as isofucoterol (4), 24R,28S and 24S,28R-epoxy-24-ethylcholesterol (5), and (24S)-stigmastadiene-3β,24-diol (6) on the basis of spectroscopic data analyses and comparison with those reported in the literature. Compounds 4–6 were isolated from U. australis for the first time. These compounds, together with the previously isolated secondary metabolites of this alga, were investigated for their inhibitory effects on human recombinant aldose reductase in vitro. Of the compounds, 24R,28S and 24S,28R-epoxy-24-ethylcholesterol (5), 1-O-palmitoyl-3-O-(6′-sulfo-α-d-quinovopyranosyl) glycerol, (2S)-1-O-palmitoyl-3-O-[α-d-galactopyranosyl(1→2)β-d-galactopyranosyl] glycerol, 4-hydroxybenzoic acid, 4-hydroxyphenylacetic acid, and 8-hydroxy-(6E)-octenoic acid weakly inhibited the enzyme, while the three new sterols, 1–3, were almost inactive.

Targeting activator protein 1 signaling pathway by bioactive natural agents: Possible therapeutic strategy for cancer prevention and intervention

Activator protein 1 (AP-1) is a key transcription factor in the control of several cellular processes responsible for cell survival proliferation and differentiation. Dysfunctional AP-1 expression and activity are involved in several severe diseases, especially inflammatory disorders and cancer. Therefore, targeting AP-1 has recently emerged as an attractive therapeutic strategy for cancer prevention and therapy. This review summarizes our current understanding of AP-1 biology and function as well as explores and discusses several natural bioactive compounds modulating AP-1-associated signaling pathways for cancer prevention and intervention. Current limitations, challenges, and future directions of research are also critically discussed.