Anti-Inflammatory Activity of Glycolipids and a Polyunsaturated Fatty Acid Methyl Ester Isolated from the Marine Dinoflagellate Karenia mikimotoi

Separation, characterization and anti-inflammatory activities of galactoglycerolipids from Perilla frutescens (L.) Britton

The study was to optimize the separation procedures, characterize the galactoglycerolipids and explore their anti-inflammatory activities. Two monogalactosyldiacylglycerols (MGDGs) and three digalactosyldiacylglycerols (DGDGs) from Perilla frutescens (L.) Britton were obtained through one-step silica gel column chromatography and preparative high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). The presence of additional MGDG (1-O-9Z,12Z,15Z-octadecatrienoyl-2-O-7Z,10Z,13Z-hexadecatrienoyl-3-O-(β-D-galactopyranosyl)-sn-glycerol) and DGDG (1-O-9Z,12Z-octadecadienoyl-2-O-9Z,12Z,15Z-octadecatrienoyl-3-O-(β-D-galactopyranosyl-(1'→6'')-α-D-galactopyranosyl)-sn-glycerol) was concluded for the first time in perilla, by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). In lipopolysaccharide (LPS)-induced RAW264.7 cells, five galactoglycerolipids exhibited good inhibitory activities against nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) gene expression in a dose-dependent manner, suggesting that fatty acid chain length and unsaturation degree affected their anti-inflammatory activities.

Electroacupuncture pretreatment protects septic rats from acute lung injury by relieving inflammation and regulating macrophage polarization

BACKGROUND

Macrophage polarization toward the M2 phenotype may attenuate inflammation and have a therapeutic effect in acute lung injury (ALI).

OBJECTIVE

To investigate the role of electroacupuncture (EA) pretreatment on the inflammatory response and macrophage polarization in a septic rat model of lipopolysaccharide (LPS)-induced ALI.

METHODS

Male Sprague Dawley rats (n = 24) were randomly divided into three groups (n = 8 each): control (Ctrl), ALI (LPS) and pre-EA (LPS + EA pretreatment). ALI and pre-EA rats were injected with LPS via the caudal vein. Pulmonary edema was assessed by left upper pulmonary lobe wet-to-dry (W/D) ratios. Lung injury scores were obtained from paraffin-embedded and hematoxylin and eosin-stained sections of the left lower pulmonary lobe. Inflammatory activation was quantified using serum tumor necrosis factor (TNF)-α, interleukin (IL)-1β, transforming growth factor (TGF)-β and IL-10 levels measured by enzyme linked immunosorbent assay (ELISA). Macrophage phenotype was determined by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting.

RESULTS

Mean lung W/D ratio was significantly lower and serum IL-1β levels were decreased in pre-EA rats compared to ALI rats (P < 0.05). TNF-α mRNA expression was decreased and mannose receptor (MR) and Arg1 mRNA expression was increased in the lung tissues of pre-EA rats compared to ALI rats (P < 0.01). Arg1 protein expression was similarly increased in the lung tissues of pre-EA rats compared to ALI rats (P < 0.05).

CONCLUSION

EA pretreatment may play a protective role by promoting macrophage polarization to the M2 phenotype in a septic rat model of LPS-induced ALI.

Marine Compounds with Anti-Candida sp. Activity: A Promised “Land” for New Antifungals

Candida albicans is still the major yeast causing human fungal infections. Nevertheless, in the last decades, non-Candida albicans Candida species (NCACs) (e.g., Candida glabrata, Candida tropicalis, and Candida parapsilosis) have been increasingly linked to Candida sp. infections, mainly in immunocompromised and hospitalized patients. The escalade of antifungal resistance among Candida sp. demands broadly effective and cost-efficient therapeutic strategies to treat candidiasis. Marine environments have shown to be a rich source of a plethora of natural compounds with substantial antimicrobial bioactivities, even against resistant pathogens, such as Candida sp. This short review intends to briefly summarize the most recent marine compounds that have evidenced anti-Candida sp. activity. Here, we show that the number of compounds discovered in the last years with antifungal activity is growing. These drugs have a good potential to be used for the treatment of candidiasis, but disappointedly the reports have devoted a high focus on C. albicans, neglecting the NCACs, highlighting the need to perform outspreading studies in the near future.

Marine natural products

Covering: 2020This review covers the literature published in 2020 for marine natural products (MNPs), with 757 citations (747 for the period January to December 2020) 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 (1407 in 420 papers for 2020), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. A meta analysis of bioactivity data relating to new MNPs reported over the last five years is also presented.

Galactosyldiacylglycerols: From a Photosynthesis-Associated Apparatus to Structure-Defined In Vitro Assembling

Being ubiquitously present in plants, microalgae, and cyanobacteria and as the major constituents of thylakoid membranes, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) make up approximately 52 and 26%, respectively, of chloroplast lipids. Thylakoid membranes harbor the photosynthetic complexes and numerous essential biochemical pathways where MGDG and DGDG play a central role in facilitating photosynthesis light reaction, maintaining chloroplast morphology, and responding to abiotic stresses. Furthermore, these galactolipids are also bioactive compounds with antitumor, antimicrobial, antiviral, immunosuppressive, and anti-inflammatory activities and important nutritional value. These characteristics are strictly dependent upon their fatty acyl chain length, olefinic nature, and stereoconfiguration. However, their application potentials are practically untapped, largely as a result of the fact that their availability in large quantity and high purity (structured galactolipids) is challenging. In addition to laborious extraction from natural sources, in vitro assembling of these molecules could be a promising alternative. Thus, this review updates the latest advances in elucidating biosynthesis paths of MGDG and DGDG and related enzyme systems, which present invaluable inspiration to design approaches for a retrosynthesis of galactolipids. More critically, this work summarizes recent developments in the biological and enzymatic syntheses of galactolipids, especially the strategic scenarios for the construction of in vitro enzymatic and/or chemoenzymatic synthesis routes. Protein engineering of enzymes involved in the synthesis of MGDG and DGDG to improve their properties is highlighted, and the applications of galactolipids in foods and medicine are also discussed.

Glycoglycerolipids from the leaves of Perilla frutescens (L.) Britton (Labiatae) and their anti-inflammatory activities in lipopolysaccharide-stimulated RAW264.7 cells

A described monogalactosyldiacylglycerol (MGDG) and two undescribed digalactosyldiacylglycerols (DGDGs) were isolated from the leaves of Perilla frutescens (L.) Britton (Labiatae) by using silica gel column chromatography and semi-preparative high performance liquid chromatography. The elucidation of complete structure of these compounds were conducted by using MS and NMR techniques. The MGDG (7.5% of total lipids) was identified as 1,2-2-O-(9Z,12Z,15E-octadecatrienoyl)-3-O-(β-D-galactopyranosyl)-sn-glycerol. The two DGDGs (2.8% and 1.0% of total lipids, respectively) were identified as 1-O-(9Z,12Z,15Z-octadecatrienoyl)-2-O-(6Z,9Z,12Z-octadecatrienoyl)-3-O-[β-D-galactopyranosyl-(1″→6')-α-D-galactopyranosyl]-sn-glycerol and 1-O- hexadecanoyl -2-O-(9Z,12Z,15Z-octadecatrienoy -l)-3-O-[β-D-galactopyranosyl-(1″→6')-α-D-galactopyranosyl]-sn-glycerol, respectively. All the isolated MGDG and DGDGs were evaluated for their anti-inflammatory activities in lipopolysaccharide (LPS)-stimulated murine macrophages RAW264.7 cells. All of them showed good inhibitory activities and significantly blocked the production of LPS-induced TNF-α, (IL)-1β and IL-6. The above results shed some light on a better understanding of the traditional anti-inflammatory effect of Perilla frutescens and reveal the potential anti-inflammatory constituents.

Toxic effects of the dinoflagellate Karenia mikimotoi on zebrafish (Danio rerio) larval behavior

Karenia mikimotoi is a toxic dinoflagellate that forms harmful blooms in coastal waters, threatening aquaculture worldwide. However, we do not know whether K. mikimotoi has a neurotoxic effect on aquatic animal behavior. Thus, this study investigated potential K. mikimotoi neurotoxicity in zebrafish larvae. Cells of K. mikimotoi were collected at the mid-exponential phase from a batch culture to prepare ruptured cell solutions (RCS). At 6 h post-fertilization (hpf), zebrafish embryos were exposed to different RCS concentrations (0, 10², 10³, 10⁴, and 2.5 × 10⁴ cells mL^-1). After 120 hpf, treated larvae were collected to analyze locomotor behavior; activities of acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CAT); and expression of genes related to neurodevelopment. We found that RCS did not affect survival rate, but significantly decreased larval locomotion, as well as their AChE, SOD, and CAT activity. Additionally, the examination of the day-night behavioral experiment revealed RCS decreased locomotion only at night. Zebrafish larvae were also significantly hypoactive in response to light and sound stimulations. Of the neurodevelopment genes, three (th, neurog1, and neurod1) were downregulated, while two (bdnf and manf) were upregulated. Our study suggests that K. mikimotoi neurotoxicity occurs through causing oxidative damage, as well as disorders in the cholinergic system and nervous system development. The results provide new insight that K. mikimotoi in low abundance did not cause significant lethal effect but still exhibited significant neurotoxicity on aquatic animals.

Systematic approach in macrophage polarization experiments: Maintaining integrity and reproducibility using flow cytometry and sample preparation

Resolution of inflammation is an important physiological process following infection or injury. When inflammation fails to resolve, it can cause chronic inflammation, which exacerbates a myriad of diseases. Current anti-inflammatory treatment options are often inadequate to resolve inflammation, and as such, a key goal for drug discovery is to find natural products and novel compounds that can target immune resolution processes. In order to efficiently discovery new therapies, immune cell lines are often used, in conjunction with flow cytometry, to quickly and inexpensively screen potential drugs for immunomodulatory effects. However, seemingly minor or trivial differences in methodology can lead to inconsistent results across experiments and across laboratories. It was the goal of this project to examine the effects of those differences on the RAW 264.7 macrophage cell line, particularly as it relates to macrophage polarization experimentation. We found that the type of detachment method when preparing cells for flow cytometry can alter several key macrophage parameters, including markers for macrophage polarization, depending on the gating strategy used in identifying sub-populations of cells for analysis. Investigators need to incorporate best-practices in gating strategy in order to target viable cells that are not in aggregate to ensure consistent and reliable results for immunomodulatory drug discovery.

Lipids Composition in Plant Membranes

The paper focuses on the selected plant lipid issues. Classification, nomenclature, and abundance of fatty acids was discussed. Then, classification, composition, role, and organization of lipids were displayed. The involvement of lipids in xantophyll cycle and glycerolipids synthesis (as the most abundant of all lipid classes) were also discussed. Moreover, in order to better understand the biomembranes remodeling, the model (artificial) membranes, mimicking the naturally occurring membranes are employed and the survey on their composition and application in different kind of research was performed. High level of lipids remodeling in the plant membranes under different environmental conditions, e.g., nutrient deficiency, temperature stress, salinity or drought was proved. The key advantage of lipid research was the conclusion that lipids could serve as the markers of plant physiological condition and the detailed knowledge on lipids chemistry will allow to modify their composition for industrial needs.

Quantitative PCR assay for the simultaneous identification and enumeration of multiple Karenia species

Quantitative PCR (qPCR) is the method of choice for specific detection and quantification of harmful algal bloom (HAB) species. Development of qPCR assay for simultaneous enumeration of species that frequently co-exist in HABs is required. A high sensitivity TaqMan qPCR assay, using probe and primers, located at ITS1-5.8S-ITS2 rDNA region, detecting, specifically, Karenia selliformis, K. bidigitata, and K. mikimotoi, was designed. ITS1-5.8S-ITS2 rDNA region copy numbers per Karenia cell genome were estimated to 217.697 ± 67.904, allowing cell quantification. An application of the designed methodology in field samples has been conducted, and it showed high sensitivity (detection of around 10^-1 cell/100 mg of bivalve mollusk tissue, equivalent to about 20 copies of the target sequence). We suggest that the optimized method could contribute to early detection of three closely related Karenia species in seafood cultivating areas to promote control quality, guarantee a fast and effective intervention, and improve public health prevention.