Dictyopteris Membranacea Research Articles

Extraction, Physicochemical Characterization and Pharmacological Evaluation of Alginate from a Mediterranean Species of Brown Algae Dictyopteris membranaceae

Brown seaweeds have attracted the attention of research. Alginates, one of the components of brown seaweed, are the subject of our study. In this work, we present the extraction, the physico-chemical characterization and the pharmacological evaluation of alginate from the brown seaweed Dictyopteris membranaceae. The extraction of alginates from brown seaweed was conducted using Rioux et al. method with few modifications. The characterization of alginates was then preceded by infra-red spectroscopy. The content of different components was determined using Ultraviolet-visible spectroscopy. Molecular properties were determined using size exclusion chromatography. The results of our study showed that the yield of extraction of alginate from Dictyopteris membranacea is 7% of dry weight. Protein, total sugar and alginic acid content were determined using colorimetric assays. The results are comparable to those reported in literature. The infra-red spectrum confirmed the nature of our extract. The molecular weight is 77823 Daltons. Additionally, our extract presented a higher gastroprotective activity at 200mg/Kg than sucralfate administered at the same dose. Our results suggest that alginate from Dictyopteris membranaceae could be used as a gastroprotective agent.

Extraction of the Volatile Oils of Dictyopteris membranacea Batters 1902 by Focused Microwave-assisted Hydrodistillation and Supercritical Carbon Dioxide: Empirical Kinetic Modelling Approach, Apparent Solubility and Rate Constants

Extraction of the Volatile Oils of Dictyopteris membranacea Batters 1902 by Focused Microwave-assisted Hydrodistillation and Supercritical Carbon Dioxide: Empirical Kinetic Modelling Approach, Apparent Solubility and Rate Constants

Biochemical characterization of eight Greek algae as candidate species for local seaweed cultivation

Abstract Seaweeds cover a wide range of applications, e.g. as food supplements, in animal feed, as biofuels or as sources of bioactive compounds. The Greek coast in the East Mediterranean is rich in various seaweeds that remain unexploited because their chemical and nutritional content has not yet been characterized. In the present study, eight seaweeds belonging to the Rhodophyta, Ochrophyta (class Phaeophyceae) and Chlorophyta were biochemically characterized and evaluated as potential food sources. Total polyphenol content, antioxidant activity, fatty acids and elemental composition were measured. Acanthophora nayadiformis, Ceramium sp. (Rhodophyta), Codium fragile (Chlorophyta), Cystoseira foeniculacea and Gongolaria barbata (formerly Cystoseira barbata) (Ochrophyta, Phaeophyceae) had the highest phenolic content and strongest antioxidant activity. Both brown and red seaweeds were rich in minerals, with G. barbata, Dictyopteris polypodioides (formerly Dictyopteris membranacea) (Chlorophyta, Phaeophyceae) and A. nayadiformis being the richest in macro- and microelements. The low Na/K ratio in most seaweeds (0.03–3.49) and the high iron content of red and brown algae (1.01–52.40 mg 100 g−1 of wet tissue) make algal consumption an attractive option. Chlorophyta and Phaeophyceae had the lowest n-6/n-3 PUFA ratios, with α-linolenic acid being the most abundant n-3 PUFA. The green algae Codium fragile and Ulva lactuca had the highest oleic and docosahexaenoic acid content, respectively. Finally, Rhodophyta were the highest producers of eicosapentaenoic acid. The findings confirmed the nutritional value of all seaweeds, highlighting brown seaweeds Cystoseira foeniculacea, G. barbata, and D. polypodioides as potential sources for food supplements and candidate species for seaweed cultivation in Mediterranean coastal waters.

Disulfides from the Brown Alga Dictyopteris membranacea Suppress M1 Macrophage Activation by Inducing AKT and Suppressing MAPK/ERK Signaling Pathways.

Inflammation is part of the organism’s response to deleterious stimuli, such as pathogens, damaged cells, or irritants. Macrophages orchestrate the inflammatory response obtaining different activation phenotypes broadly defined as M1 (pro-inflammatory) or M2 (homeostatic) phenotypes, which contribute to pathogen elimination or disease pathogenesis. The type and magnitude of the response of macrophages are shaped by endogenous and exogenous factors and can be affected by nutrients or therapeutic agents. Multiple studies have shown that natural products possess immunomodulatory properties and that marine algae contain products with such action. We have previously shown that disulfides isolated from Dictyopteris membranacea suppress nitric oxide (NO) production from activated macrophages, suggesting potential anti-inflammatory actions. In this study, we investigated the anti-inflammatory mechanism of action of bis(5-methylthio-3-oxo-undecyl) disulfide (1), 5-methylthio-1-(3-oxo-undecyl) disulfanylundecan-3-one (2) and 3-hexyl-4,5-dithiocycloheptanone (3). Our results showed that all three compounds inhibited M1 activation of macrophages by down regulating the production of pro-inflammatory cytokines TNFα, IL-6 and IL-12, suppressed the expression of the NO converting enzyme iNOS, and enhanced expression of the M2 activation markers Arginase1 and MRC1. Moreover, disulfides 1 and 2 suppressed the expression of glucose transporters GLUT1 and GLUT3, suggesting that compounds 1 and 2 may affect cell metabolism. We showed that this was due to AKT/MAPK/ERK signaling pathway modulation and specifically by elevated AKT phosphorylation and MAPK/ERK signal transduction reduction. Hence, disulfides 1–3 can be considered as potent candidates for the development of novel anti-inflammatory molecules with homeostatic properties.

Chemical screening and antibacterial activity of essential oil and volatile fraction of Dictyopteris polypodioides

The genus Dictyopteris, comprising 35 species, is known by its characteristic marine fragrances which is mainly associated to aspecific chemical composition. Dictyopteris polypodioides (D. polypodioides), known as Dictyopteris membranacea (D. membranacea), is distributed in several region of the world and characterized by a wide range of bioactive compounds. In the current research, the chemical composition and antibacterial activity of the volatile fraction (VF) and essential oil (EO) of D. polypodioides are reported in a comparative objective. The VF was prepared from the crude ether extract, whereas, the EO was made from the dried alga. The GC/MS analysis of the VF and the EO revealed the presence of 72 and 70 compounds accounting for 86.4% and 80.6% of the total composition respectively. The main constituents in both oils were 3-hexyl-4,5-dithiacycloheptanone and dictyopterene. The antibacterial activity of the VF and the EO were evaluated by liquid-broth dilution method, against six strains including Staphylococcus aureus, Agrobacterium tumefaciens, Salmonella typhimurium, Bacillus cereus, Micrococcus luteus and Escherichia coli. Kanamycin and chloramphenicol were used as antibiotics references.The EO has shown a high inhibitory effect against all the microorganisms tested as compared to the VF. Staphylococcus aureus and Agrobacterium tumefaciens were the most sensitive bacteria with respect to the EO, where the MIC was around 1519 μg/mL. This strong antibacterial activity of the EO is related to the presence of high content of sulfur compounds, known by their broad spectrum of biological activities.

Chemical characterization of essential oils and antioxidant activity of Dictyota dichotoma and Dictyopteris membranacea

The work focuses on the study of two brown algae Dictyota dichotoma and Dictyopteris membranacea. Extracts obtained by different organic solvents (dichloromethane, hexane, acetone, methanol, chloroform) were screened for their DPPH antiradical activity, whereas essential oils obtained by steam distillation were chemically characterized by GC-MS. Steam distillation yielded 0.07 and 0.095% of the essential oils for Dictyota dichotoma and Dictyopteris membranacea, respectively. The chemical screening of the essential oils of Dictyopteris membranacea and Dictyota dichotoma showed similar chemical profiles. Namely, trans-anethole showed to be the main component in both studied oils, yielding 12.28% and 10.70% for Dictyopteris membranacea and Dictyota dichotoma, respectively. Antioxidant activity of extracts was expressed by IC50 values and was in the range 0.375-1.72 mg/ml.

Food selection of a generalist herbivore exposed to native and alien seaweeds

Understanding which factors influence the invasion of alien seaweed has become a central concern in ecology. Increasing evidence suggests that the feeding preferences of native herbivores influence the success of alien seaweeds in the new community. We investigated food selection of a generalist native grazer Paracentrotus lividus, in the presence of two alien seaweeds (Caulerpa cylindracea and Caulerpa taxifolia var. distichophylla) and two native seaweeds (Dictyopteris membranacea and Cystoseira compressa). Sea urchins were fed with six experimental food items: C. cylindracea, C. taxifolia var. distichophylla, a mixture of C. cylindracea and C. taxifolia var. distichophylla, D. membranacea, C. compressa and a mixture of D. membranacea and C. compressa. P. lividus ingested all the combinations of food offered, though it preferentially consumed the alien mixture, C. cylindracea and D. membranacea. The alien C. taxifolia var. distichophylla was consumed significantly less than the other food items and, interestingly, it was ingested in a greater amount when mixed with C. cylindracea than when on its own. This finding suggests that C. taxifolia var. distichophylla may become vulnerable to sea urchin grazing when it grows intermingled with C. cylindracea, which does not gain immediate protection from the presence of the very low palatable congeneric seaweed. The present study highlights the potential role of native grazers to indirectly affect the interspecific competition between the two alien seaweeds in the Mediterranean Sea.

Phytochemical and in vitro antimicrobial and genotoxic activity in the brown algae Dictyopteris membranacea

The emergence and increase of microbial resistance towards many conventional therapeutics necessitate the investigation and discovery of new natural sources of antimicrobial agents. In this study the Mediterranean brown alga, Dictyopteris membranacea, was investigated. The total phenolic, flavonoid and tannin contents were quantified and antibacterial, antifungal and antitubercular activities of the crude extract and semi-purified ethanol, acetone and methanol/CH2Cl2 fractions were determined. The antimicrobial activity was determined by the agar diffusion method against six strains of Gram-positive, two strains of Gram-negative bacteria and one yeast strain. The MIC and MBC or MFC values served to identify the bactericidal and bacteriostatic effects of all prepared fractions against the different strains. The acetone fraction presented a source of phenolic (112mgGAE/g of sample) and tannin (130mgCAE/g sample) compounds whereas the ethanol fraction showed the highest concentration of flavonoids (120mgQE/g). Ethanol and acetone fractions exhibited considerable antibacterial, antifungal and antitubercular activities with a good correlation between the phytochemical composition of all prepared fractions and the different biological activities.This study on the phytochemical and in vitro antimicrobial activity of this brown alga was supplemented by an in vitro investigation of the potential genotoxicity of the extract and fractions using the bacterial Vitotox test and micronucleus test on human C3A cells. The results show that all prepared fractions were not genotoxic in the presence or absence of S9.Overall, the results are therefore encouraging and justify further investigations on the therapeutic and other values of this alga.

Disulfides with Anti-inflammatory Activity from the Brown Alga Dictyopteris membranacea.

Six new (1, 2, and 4-7) and two previously reported (3 and 8) disulfides, along with 4-butyl-2,6-cycloheptadienone, γ-tocopherol, and δ-tocopherol, were isolated from an organic extract of the brown alga Dictyopteris membranacea, collected at Gerolimenas Bay, Greece. The structure elucidation of the isolated natural products was based on analysis of their spectroscopic data. Compounds 1, 3-6, and 8 were evaluated for their antibacterial and anti-inflammatory activities. None of the compounds displayed antibacterial activity against two resistant strains of Staphylococcus aureus and one strain of Escherichia coli. In contrast, metabolite 5 was able to cause strong inhibition of NO production with an IC50 value of 3.8 μM using an LPS stimulation assay.

Evaluation of the Genotoxicity and Cytotoxicity of Semipurified Fractions from the Mediterranean Brown Algae, Dictyopteris membranacea.

Dictyopteris membranacea, a species of Mediterranean brown algae, is believed to have potential pharmacological and nutritional applications. However, such potentials only make sense when devoid of any adverse health consequences. The present study should be seen in this context. It aimed at evaluating the genotoxicity and cytoxicity of its organic extract (F0) and semi purified fractions (F4, F5, and F6). Extracts were tested using the bacterial Vitotox® test and micronucleus assay in different concentrations (from 1.25 μg/mL up to 100 μg/mL, depending on the test and the extract). Applied concentrations were based on a preliminary dose-finding test with the neutral red uptake assay. The results show that all extracts were not genotoxic in the presence or absence of a rat metabolic enzyme fraction (S9). This is encouraging and justifies further investigations on the therapeutic and other values of this algae.SUMMARY Dictyopteris membranacea extracts and some of their semi purified fractions have important antibacterial properties.The organic extract (F0) and semi purified fractions (F4, F5, and F6) were not genotoxic according to the bacterial Vitotox test.They were also not genotoxic according to the micronucleus test in human C3A cells.Applied concentrations were based on the in-vitro neutral red uptake (NRU) test.

Water soluble polysaccharides extracted from Pterocladia capillacea and Dictyopteris membranacea and their biological activities

Cold and hot water extracts (CWE, HWE) of both the red alga Pterocladia capillacea (P. capillacea) and the brown alga Dictyopteris membranacea (D. membranacea) were studied for their polysaccharide contents. In both (CWE) and (HWE) extracts. Relatively higher yields were obtained in case of P. capillacea pillacea (2.87 and 6.46%, respectively). The polysaccharide contents of the CWE hydrolyzate of both studied algae analyzed by HPLC were found to be enriched with glucuronic acid, arabinose and glucose, whereas, HWE hydrolyzate were found to be rich in glucuronic acid and fructose. The polysaccharide contents of the CWE and HWE extracts of (D. membranacea) showed appreciable antimicrobial activity in addition to a moderate antitumor activity against HELA (Cervix carcinoma cell line) at IC50=9.83μg/dl, respectively. Whereas the polysaccharide contents of the CWE and HWE extracts of (P. capillacea) exhibited a promising anticoagulant activity.

In vitro antibacterial activity of alkaloid extracts from green, red and brown macroalgae from western coast of Libya

Marine organisms and microorganisms are known to be a rich source of alkaloids with unique chemical feature and interesting biological activities. The current study presents the antibacterial effect of the alkaloid extracts of some green, red and brown algae were collected from western coast of Libya, against, Escherichia coli , Salmonella typhi , Klebsiella spp., and Pseudomonas aeruginosa , Staphylococcus aureus , Bacillus subtilis , Bacillus spp. and Staphylococcus epidermidis were investigated. Although alkaloid extracts of green algae inhibited all tested bacteria, maximum effect was exhibited by brown and red algae species. Thus, Cystoseira barbata alkaloid extract showed remarkable inhibition of human pathogen Klebsiella spp. Dictyopteris membranacea alkaloid extract also demonstrated similar considerable effect against S. typhi with MIC value 1.56 mg/ml. The pronounced antibacterial activity of C. barbata and D. membranacea can be attributed to their high alkaloid contents. These results suggest that red and brown algae secondary metabolites are important sources that could produce potential chemotherapeutic agents. Key words : Macroalgae, alkaloids, antibacterial activity.

Spectroscopic studies of molecular iodine emitted into the gas phase by seaweed

Abstract. Time profiles of molecular iodine emissions from seven species of seaweed have been measured at high time resolution (7.5 s) by direct spectroscopic quantification of the gas phase I2 using broadband cavity enhanced absorption spectroscopy. Substantial differences were found between species, both in the amounts of I2 emitted when the plants were exposed to air and in the shapes of their emission time profiles. Two species of kelp, Laminaria digitata and Laminaria hyperborea, were found to be the most potent emitters, producing an intense burst of I2 when first exposed to air. I2 was also observed from Saccharina latissima and Ascophyllum nodosum but in lower amounts and with broader time profiles. I2 mixing ratios from two Fucus species and Dictyopteris membranacea were at or below the detection limit of the present instrument (25 pptv). A further set of experiments investigated the time dependence of I2 emissions and aerosol particle formation when fragments of L. digitata were exposed to desiccation in air, to ozone and to oligoguluronate stress factors. Particle formation occurred in all L. digitata stress experiments where ozone and light were present, subject to the I2 mixing ratios being above certain threshold amounts. Moreover, the particle number concentrations closely tracked variations in the I2 mixing ratios, confirming the results of previous studies that the condensable particle-forming gases derive from the photochemical oxidation of the plant's I2 emissions. This work also supports the theory that particle nucleation in the coastal atmosphere occurs in "hot-spot" regions of locally elevated concentrations of condensable gases: the greatest atmospheric concentrations of I2 and hence of condensable iodine oxides are likely to be above plants of the most efficiently emitting kelp species and localised in time to shortly after these seaweeds are uncovered by a receding tide.

Anti-inflammatory, antioxidant and antimicrobial activities of aqueous and organic extracts fromDictyopteris membranacea

AbstractAqueous and organic extracts fromDictyopteris membranaceacollected from the Tunisian Mediterranean coast were studied for their anti-inflammatory, antioxidant and anti-microbial activities. All extracts had high anti-inflammatory activity in carrageenan-induced rat paw edema assays in Wistar rats, and their effects are comparable to acetylsalicylate lysine (300 mg kg-1, applied intraperitoneally) used as a reference drug.Dictyopteris membranaceaextracts had inhibition percentages in the third hour of the assay of 65% at a dose of 100 mg kg-1, 51% at a dose of 50 mg kg-1, and 49% at a dose of 100 mg kg-1in aqueous, chloroform and ethyl acetate extracts, respectively. Chloroform and ethyl acetate extracts exhibited 2,2-diphenyl-1-picrylhydrazyl radical scavenging with IC50values (0.089±0.01 and 0.11±0.02 mg ml-1, respectively) equivalent to the activity of a powerful antioxidant standard, Trolox (IC50=0.09±0.02 mg ml-1). These extracts (chloroform and ethyl acetate) had reducing activity, and the total phenol contents were: 84.96 and 60.96 mg gallic acid equivalent per gram dried sample, respectively. Organic extracts had moderate antimicrobial activity (using the disc diffusion method) against three bacteria:Staphylococcus aureus,Staphylococcus epidermidisandMicrococcus luteus, and four species of a fungal genus:Candida albicans,C. krusei,C. dubliniensisandC. kefyrat 10 mg per disc, whereas the aqueous extract exhibited significant antibacterial activity against onlyStaphylococcus aureusandListeria monocytogenes.

SEASONAL VARIATION AND ANTIFUNGAL ACTIVITIES OF METHANOLIC ALGAL EXTRACTS OF SOME DICTYOTACEAE OF BENGHAZI COASTS, LIBYA

The results evaluated the efficiency of all used algal extracts with high significant differences and could be arranged dissentingly as Dictyota linearis > Dictyota dichotoma var. dichotoma > Dictyopteris membranacea > Padina pavonica (Dictyotaceae). The methanolic used algal extracts of spring and summer were more efficient without significant difference while the algal extractions of autumn came at the second rank with significant difference. The used fungi were Aspergillus niger, Aspergillus flavus, Penicilium parasiticus, Fusarium oxysporum, Fusarium solani and Candida utilis. All of them were affected by all used algal extracts without significant difference.

Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown (Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds (Gelidium sesquipedale, Sphaerococcus coronopifolius) from Sao Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga–herbivore interactions.

Comparison of various extraction methods for identification and determination of volatile metabolites from the brown alga Dictyopteris membranacea

Three different methods: hydrodistillation (HD), focused microwave-assisted hydrodistillation (FMAHD) and supercritical fluid extraction (SFE) have been applied, for the first time together, for the extraction of volatile metabolites of the brown alga Dictyopteris membranacea. The oils obtained were analyzed by GC–MS (identification and determination of metabolites) and the results were compared. The main chemical classes of compounds identified were C11 hydrocarbons for HD method, sesquiterpenes for FMAHD method and sulphur compounds for SFE method.

Isolation of the Volatile Compounds from the Brown Alga Dictyopteris membranacea by Focused Microwave-Assisted Hydrodistillation

A new method of hydrodistillation assisted by a focused microwave oven was applied to the essential oil production of the brown alga Dictyopteris membranacea. This oil was analyzed by GC and GC/MS and the results were compared with those of conventional hydrodistillation. The concentration of the volatile CM 1 hydrocarbons was higher in the focused microwave-assisted hydrodistillation, while the yield of heavy compounds was lower.

Chemical defense of brown algae (Dictyopteris spp.) against the herbivorous amphipod Ampithoe longimana.

Terpenoids, polyphenols, and C11 metabolites are broadly distributed among brown seaweeds. Terpenoids and polyphenols have often been investigated as chemical defenses against herbivores, while there are only few investigations of the fatty-acid-derived C11 hydrocarbons and C11 sulfur compounds as potential defenses. We investigated effects of C11 sulfur metabolites from the cosmopolitan brown alga Dictyopteris membranacea on feeding and fitness of the herbivorous amphipod Ampithoe longimana. In choice tests between freshly collected thalli of D. hoytii (which lacks C11 sulfur compounds) and D. membranacea (which contains C11 sulfur compounds) amphipods consumed about 4 times more of the species lacking the C11 sulfur compounds. The same feeding preference was observed when these plants were finely ground and embedded in an agar matrix to destroy morphological differences. When a diet made from field-collected thalli of D. membranacea containing C11 sulfur compounds was tested against a diet made from a laboratory culture of D. membranacea that had lost the ability to produce C11 sulfur compounds, the same magnitude of preference was observed for the population lacking the sulfur compounds. In addition to the C11 sulfur compounds, a water-soluble C9-oxo acid that appears to be a by-product in the biosynthesis of the C11 metabolites also suppressed amphipod feeding to a comparable extent. Both classes of compound may contribute to the effective chemical protection of D. membranacea. When juvenile amphipods were reared for 28days on artificial diets containing the above compounds, their survivorship (≤10%) closely resembled that of a starved treatment, but differed dramatically from a control treatment (60%) consisting of the same food, but without the metabolites. Most other classes of brown algal secondary metabolites are defensive against a broad spectrum of larger herbivores, but relatively ineffective against the amphipod studied here. In contrast, the fatty-acid-derived sulfur compounds and the C9-oxo acid strongly deter Ampithoe-like mesograzers but appear less effective against other herbivores, suggesting that these metabolites could be ecologically important in defending zygotes and germlings against these small consumers.

Study of the correlation between trace elements, sterols and fatty acids in brown algae from the Saronikos gulf of Greece

In the whole plant of brown algae species Colpomenia sinuosa, Cystoseira compressa, Dictyopteris membranacea, Dictyota dichotoma, Dictyota linearis, Padina pavonica, Sargassum accinarium and Stypocaulon scoparium collected from Saronikos gulf of Greece, the trace elements antimony, cesium, chromium, cobalt, europium, iron, rubidium, scandium, strontium, thorium and zinc were determined by instrumental neutron activation analysis. In the same samples the sterols campesterol, cholesterol, fucosterol stigmasterol and the fatty acids linoleic, linolenic, myristic, oleic, palmitic, palmitoleic and stearic acid were determined by gas-liquid chromatography. Statistical analysis included the calculation of the correlation coefficient and multiple correlation was applied in all analytical data. The results showed that the sterol pattern of Padina pavonica is different from all the other examined species. A high fucosterol content should be accompanied by very low concentrations or absence of a number of other constituents. Linoleic and linolenic acids present a strong linear correlation between them. Stearic acid seems to play a role in the life process of brown algae due to its significant correlation with fucosterol and with strontium. The high content found for the latter must be an evidence for the selective accumulation of this element from brown algae as mentioned in literature. A multiple correlation was found between sterols, saturated fatty acids and other single constituents studied in this work.