K. K. Asanka Sanjeewa

A fucoidan fraction purified from Chnoospora minima; a potential inhibitor of LPS-induced inflammatory responses

Fucoidans are an interesting group of bioactive sulfated polysaccharides abundant in brown seaweeds. The current study highlights the enrichment and extraction of fucoidan from Chnoospora minima by means of enzyme-assistant extraction using Celluclast and evaluation of its anti-inflammatory potential through in vitro and in vivo studies. The purified C. minima fucoidan (F2,4) inhibited the nitrous oxide (NO) production (IC50=27.82±0.88μg/ml) and expression of PGE2 through the subsequent downregulation of iNOS and COX-2 expression in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophages. F2,4 downregulated TNF-α, IL1-β, and IL-6 in RAW 264.7 macrophages in a dose-dependent manner and suppressed NO and ROS production in LPS stimulated zebrafish embryos while exerting a protective effect against the cell damage caused by LPS. Polysaccharide structural characterization was performed using FTIR, HPAE-PAD analysis of the monosaccharide content and NMR spectroscopy. Current findings confirm the potential anti-inflammatory activity of fucoidan purified from C. minima and elaborate its potential application as a functional ingredient in consumer products.

Apoptotic and antiproliferative properties of 3β‐hydroxy‐Δ5‐steroidal congeners from a partially purified column fraction of Dendronephthya gigantea against HL‐60 and MCF‐7 cancer cells

Organisms belonging to the genus Dendronephthya are among a group of marine invertebrates that produce a variety of terpenoids with biofunctional properties. Many of these terpenoids have been proven effective as anticancer drugs. Here, we report the antiproliferative effect of 3β‐hydroxy‐Δ5‐steroidal congeners against the proliferation of HL‐60 human leukemia cells and MCF‐7 human breast cancer cells. The sterol‐rich fraction (DGEHF2‐1) inhibited the growth of HL‐60 and MCF‐7 cells with IC50 values of 13.59 ± 1.40 and 29.41 ± 0.87 μg ml–1 respectively. Treatment with DGEHF2‐1 caused a dose‐dependent increase in apoptotic body formation, DNA damage and the sub‐G1 apoptotic cell population. Moreover, DGEHF2‐1 downregulated the expression of Bcl‐xL while upregulating Bax, caspase‐9, and PARP cleavage in both HL‐60 and MCF‐7 cells. The steroid fraction was found to act via the mitochondria‐mediated apoptosis pathway. Identification of the sterols was performed via gas chromatography–tandem mass spectrometry analysis. Studying the mechanism of the anticancer effect caused by these sterol derivatives could lead to the identification of other natural products with anticancer properties.

The potential of brown-algae polysaccharides for the development of anticancer agents: An update on anticancer effects reported for fucoidan and laminaran

In recent decades, attention to cancer-preventive treatments and studies on the development of anticancer drugs have sharply increased owing to the increase in cancer-related death rates in every region of the world. However, due to the adverse effects of synthetic drugs, much attention has been given to the development of anticancer drugs from natural sources because of fewer side effects of natural compounds than those of synthetic drugs. Recent studies on compounds and crude extracts from marine algae have shown promising anticancer properties. Among those compounds, polysaccharides extracted from brown seaweeds play a principal role as anticancer agents. Especially, a number of studies have revealed that polysaccharides isolated from brown seaweeds, such as fucoidan and laminaran, have promising effects against different cancer cell types in vitro and in vivo. Herein, we reviewed in vitro and in vivo anticancer properties reported for fucoidan and laminaran toward various cancer cells from 2013 to 2016.

Reduction of heavy metal (Pb2+) biosorption in zebrafish model using alginic acid purified from Ecklonia cava and two of its synthetic derivatives

Heavy metal contamination has become a major problem that causes severe environmental and health issues due to their biosorption, bioaccumulation, and toxicity. This study was designed to evaluate heavy metal chelating abilities of alginic acid (AA) extracted from the brown seaweed Ecklonia cava and two of its derivatives prepared by the partial oxidation of the 2° OH groups (OAA) and partial carboxylation of the monomeric units (CAA) upon reducing the heavy metal biosorption in zebrafish (Danio rerio) modal. Metal ions were quantified using ICP-OES and biopolymers were characterized by FTIR and XRD analysis. All investigated biopolymers indicated potential ability for chelating Pb2+, Cu2+, Cd2+, As3+, and Ag+. The sorption capacities were in the order of CAA>OAA>AA. All biopolymers indicated a comparatively higher chelation towards Pb2+. AA, OAA, and CAA could effectively reduce Pb2+ induced toxicity and Pb2+ stress-induced ROS production in zebrafish embryos. Besides, they could reduce the biosorption of Pb2+ in adult zebrafish which could lead to bioaccumulation. Since alginic acid purified from E. cava and its derivatives could be utilized as seaweed derived biopolymers to purify heavy metals contaminated water and as a dietary supplement to reduce heavy metal biosorption in organisms.

Identification of sterols from the soft coral Dendronephthya gigantea and their anti-inflammatory potential

Exploration of anti-inflammatory phytochemicals has received tremendous attention worldwide owing to the rapid increase in inflammatory diseases. Current study reveals the identification of eight 3β-hydroxy-Δ5-steroidal congeners from a nonpolar column fraction of the ethanol solubles from the soft coral Dendronephthya gigantea collected from Jeju Island South Korea, using GC-MS/MS analysis. The sterol-rich fraction (DGEH21) showed a significant anti-inflammatory activity as exhibited by the inhibition of NO production (IC50 4.33±0.50μg/mL) and PGE2 production in LPS-stimulated RAW 264.7 macrophages. It also suppressed the expression levels of proinflammatory cytokines, TNF-α, IL-1β, and IL-6 in a dose-dependent manner. Furthermore, DGEH21 effectively downregulated the expression levels of iNOS, and COX-2 and reduced NO and ROS production as well as cell death in LPS-stimulated in-vivo zebrafish embryo model. However, DGEH21 at relatively high concentrations indicated cytotoxicity in both RAW cells and zebrafish embryos with RAW cell viability being nearly 80% after treatment with 25μg/mL DGEH21. This study highlights the synergistic anti-inflammatory activity of several steroids found in D. gigantea. Their actions may be useful in the development of anti-inflammatory cosmeceuticals, pharmaceutical agents, and other consumer products.

Anti-inflammatory potential of alginic acid from Sargassum horneri against urban aerosol-induced inflammatory responses in keratinocytes and macrophages

The airborne particulate pollutants originating in the deserts of Mongolia and China which becomes contaminated with industrial effluents and traffic emissions while moving with the wind currents towards East Asia has recently become a serious environmental and health issue in the region. They cause asthma, collateral lung tissue damage, oxidative stress, allergic reactions, and inflammation. The current study was undertaken to evaluate the protective effects of alginate extracted from the invasive alga Sargassum horneri (SHA) against fine dust collected from Beijing, China (Chinese fine dust; CFD). It was found that CFD induces inflammation in HaCaT keratinocytes and inhibits macrophage activation. All of the particulate matter (PM) comprising CFD was < PM13 majority being < PM2.5 which is defined for mineral elements and polycyclic aromatic hydrocarbons. SHA attenuated PGE2 levels in CFD-induced HaCaT keratinocytes. The IC50 for SHA was 36.63 ± 4.11 µg mL-l. SHA also reduced the levels of COX-2, IL-6, and TNF-α, and inhibited certain key molecular mediators of the NF-κB and MAPK pathways in keratinocytes. SHA substantially reduced the levels of CFD-derived metal ions like Pb2+ and Ca2+ in keratinocytes attributable to its metal ion chelating properties. CFD-induced HaCaT keratinocyte culture media increased inflammatory responses in RAW 264.7 macrophages. These cells presented with increased levels of NO, iNOS, COX-2, PGE2, and pro-inflammatory cytokines. It was found that the aforementioned effects could be reversed in RAW 264.7 macrophages when keratinocytes were treated with SHA. Therefore, SHA could be used against fine dust-induced inflammation in keratinocytes.

The potential of fucoidans from Chnoospora minima and Sargassum polycystum in cosmetics: antioxidant, anti-inflammatory, skin-whitening, and antiwrinkle activities

Over the years, bioactive and biocompatible natural products have received increased attention as ingredients of cosmeceutical formulations owing to their robust properties compared to many of the synthetic chemicals in use. Many natural products derived from algae have shown promising cosmetizing properties. Seaweed polysaccharides, in particular, have received increased attention for their biofunctional and physicochemical characteristics. This study aimed to design a cost-effective strategy to purify fucoidans from the untapped brown algae Chnoospora minima (CMF) and Sargassum polycystum (SPF) harvested in Sri Lanka and to evaluate their cosmetizing properties. Based on Fourier transform infrared (FTIR) spectroscopy and monosaccharide composition analysis, the purified polysaccharides were rich in fucoidan. Relatively high sulfate content was detected in both fucoidans. Experiments were carried out to evaluate antioxidant, UV-protective, anti-inflammatory, antiwrinkling, and skin-whitening effects. Both CMF and SPF showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) and alkyl radical-scavenging activities, anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, considerable collagenase and elastase inhibitory properties and skin-whitening effects via direct inhibition of tyrosinase, and intracellular melanin synthesis indicating promising cosmetizing effects.

Apoptotic and antiproliferative effects of Stigmast-5-en-3-ol from Dendronephthya gigantea on human leukemia HL-60 and human breast cancer MCF-7 cells

The genus Dendronephthya encompasses marine soft corals that produce a wide spectrum of biofunctional terpenoids. Anticancer properties of these metabolites are widely exploited as potential chemotherapeutic agents. The present study reports the purification and isolation of a potential antiproliferative constituent, stigmast-5-en-3-ol from the 70% ethanol extract of the soft coral Dendronephthya gigantea. Among several other 3β-hydroxy-Δ5-steroidal congeners, stigmast-5-en-3-ol indicated prominent antiproliferative effects on HL-60 (leukemia) and MCF-7 (breast cancer) cell lines with IC50 values of 37.82 and 45.17 μg/ml respectively. Stigmast-5-en-3-ol increased apoptotic body formation, accumulation of sub G1 apoptotic cells, and DNA damage in HL-60 and MCF-7 cells. It increased the expression of Bax, caspases, and PARP cleavage while decreasing Bcl-xL levels in both cancer cell lines indicating that the effects are arbitrated via the mitochondria-mediated apoptotic pathway. Steroidal derivatives were identified by GC MS/MS and the identity of stigmast-5-en-3-ol was confirmed by NMR spectra. The present study suggests that stigmast-5-en-3-ol could be a promising candidate for anticancer drug research.

Purification and Identification of an Antioxidative Peptide from Digestive Enzyme Hydrolysis of Cutlassfish Muscle

ABSTRACT The major objective of this study was to investigate the pepsin digests of cutlassfish muscle for their antioxidant activity. The peptide isolated after 3 h of pepsin hydrolysis demonstrated the highest scavenging activity for both 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and alkyl radicals. It also had the highest yield of the isolates with the highest protein content, which was likely related to its higher degree of hydrolysis than the other hydrolysates. The antioxidant peptide purified from the 3 h pepsin hydrolysate indicated the amino acid sequence, Phe-Ser-Gly-Gly-Glu. This study suggests that cutlassfish muscle is an excellent antioxidant source and could be effectively used as a food ingredient and in pharmaceuticals.

In vitro and in vivo anti-inflammatory activities of high molecular weight sulfated polysaccharide; containing fucose separated from Sargassum horneri: Short communication

Recent studies on crude and pure compounds from Sargassum horneri have shown promising bioactive properties. However, anti-inflammatory potentials of fucose-rich sulfated polysaccharides from S. horneri have not yet been discovered. In the present study, we evaluated the in vitro and in vivo anti-inflammatory activities of four polysaccharide fractions separated from membrane filters according to their molecular weights (<5kDa (f1), 5-10kDa (f2), 10-30kDa (f3), and >30kDa (f4)). According to the results, F4 fraction inhibited the lipopolysaccharides (LPS)-induced nitric oxide (NO) (IC50=87.12μg/mL) and prostaglandin E2 production as well as pro-inflammatory cytokine production in RAW 264.7 cells through down-regulating nuclear factor-κB signaling cascade. According to the results, f4 has a potential to down-regulate LPS-induced toxicity, cell death and NO production levels in LPS-induced in vivo zebrafish embryo model. These results suggest that f4 fraction has the potential to develop functional materials or drugs to treat inflammatory diseases.