Tropical Red Alga Research Articles

Bioactive Compounds and Antioxidant Activity of Tropical Red Algae Gracilaria sp. from Bintan Island, Indonesia

Macroalgae that grow in the tropics are continuously exposed to ultraviolet radiation and sunlight. Macroalgae have self-defense to avoid damage caused by ultraviolet radiation by carrying out secondary metabolism and producing several bioactive compounds. The bioactive compounds produced have the potential to be utilized to inhibit free radicals that can cause degenerative diseases in humans. This research aims to identify bioactive compounds and determine the antioxidant activity, total phenolic compound, total flavonoid compound, and pigment content of red algae Gracilaria sp. from Bintan island. This research has the novelty of the sampling location to be later developed into a sustainable resource in the pharmaceutical field. Gracilaria sp. found in Bintan island was taken, dried in indirect sunlight, and macerated using universal solvent methanol. Phytochemical testing was conducted to determine the presence of flavonoids, steroids, triterpenoids, saponins, and tannins. Antioxidant activity was determined using DPPH as a free radical at the maximum wavelength of DPPH (515 nm) with an incubation time of 55 minutes. Total phenolic and flavonoid compounds were determined using standard solutions of gallic acid and quercetin, respectively. The results showed that the methanol extract of Gracilaria sp. contains flavonoid and tannin compounds, has a chlorophyll-a content of 0.43 mg/g, a carotenoid content of 0.91 µmol/g, the total phenolic compound of 4.67 mg/GAE g, total flavonoid compound of 2.26 mg/QE g and has antioxidant activity with IC50 value of 982.25 ppm. Utilization of Gracilaria sp extract from Bintan waters as a pharmaceutical ingredient is expected to increase prospects and sustainable use in the pharmaceutical and health fields.

Tropical red alga <italic>Compsopogon caeruleus</italic>: an indicator of thermally polluted waters of Europe in the context of temperature and oxygen requirements

The red alga Compsopogon caeruleus can generally be found in tropical and subtropical waters worldwide. In addition to its natural habitats, this species may be found in waters that receive abnormally hot water, e.g., from powerhouses. To date, the presence of C. caeruleus has not been observed in thermally polluted lacustrine ecosystems in Poland, which has a moderate climate. The thalli of this red alga were found growing on Vallisneria spiralis in Licheńskie Lake. Importantly, this paper presents a previously unknown relationship between the temperature (20, 25, 30, 35, and 40°C) and oxygen requirements of C. caeruleus (based on ex situ measurements of O<sub>2 </sub>consumption by thalli). Surprisingly, 35°C can be the optimum temperature for C. caeruleus, and this temperature is higher than the values reported by some previous thermal analyses by approximately 10°C. Additionally, we reviewed and mapped the distribution of this nonnative and mesophilic red alga in natural / seminatural water ecosystems in Europe. Finally, we propose that the occurrence of C. caeruleus mature thalli can be a novel, simple and easy-to-recognize bioindicator of artificially and permanently heated waters in moderate climate zones by a regular discharge of postindustrial water.

Phytochemical and Antioxidant Activities of Eucheuma spinosum as Natural Functional Food from North Sulawesi Waters, Indonesia.

Research to find functional food from new natural sources has caught the attention of many researchers through the characterization of phytochemicals and biological activities. One potential source of natural ingredients is the red alga Eucheuma spinosum, which has been used as a daily source of natural food. The purpose of this study was to obtain a prospective new source of natural antioxidants from various extracts of tropical red alga (E. spinosum) through several tests, which were used as determinants of whether the alga can be used as a functional food source. Algal sample was extracted with organic solvents (methanol, n-hexane, ethyl-acetate and water) and purified by a combination of normal and reverse phase chromatography methods. The algal extracts had antioxidant compounds based on free radical scavenging activities using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and superoxide dismutase (SOD). The ethyl acetate extract of E. spinosum scavenged DPPH and SOD free radicals, so that this extract was indicated contained powerful antioxidants. The result of the isolation of the antioxidant compound showed the presence of pure compound 3-(3-methoxyphenyl) propanal. This study concluded that red algae E. spinosum contained natural antioxidants which have the potential to be developed as a functional food and disease prevention and treatment. In addition, the components of these antioxidant compounds from the algae have the potential to be used as natural sources of new functional ingredients.

Ice‐Ice disease: An environmentally and microbiologically driven syndrome in tropical seaweed aquaculture

AbstractSeaweeds account for nearly 30% of global aquaculture production by volume, and their cultivation provides important opportunities for employment and wealth generation, particularly in rural coastal communities. Eucheumatoids (KappaphycusandEucheumaspp.) are tropical red algae commercially cultivated as raw material for production of carrageenans, particularly in South‐East Asia and the Western Indian Ocean region. Diseases and pests are major limiting factors in eucheumatoid production, particularly a condition known as ‘ice‐ice’ disease (IID). IID is characterized by bleaching of the thallus followed by the disintegration of affected tissues, leading to a loss of biomass and reduced carrageenan yield. IID has been associated with unfavourable changes in environmental conditions, particularly an increase in sea water temperature and a decrease in salinity, and infection by opportunistic or pathogenic bacteria. However, given that no single or combined causal agents have been definitely identified, IID may be considered a complex pathobiotic syndrome in which multiple factors contribute to the development of disease signs. Here, we review current knowledge of the abiotic and biotic factors associated with the development of IID, and the strategies employed to mitigate economic losses resulting from disease outbreaks. We discuss syndromic diseases in other marine holobionts, particularly other red algae and corals, in relation to their similarity to IID, and suggest the application of comprehensive and complementary methodologies, including high‐throughput sequencing and high‐quality microscopy, for enhancing our understanding of the pathological and microbiological processes associated with IID signs.

On the efficacy of an Ascophyllum-based, soluble extract in association with standard plant growth regulators on the micropropagation of the agarophyte, Gracilaria blodgettii, from seaweed farms located at the northern entrance of the Panama Canal

Gracilaria spp. (agarophytes) are cultivated by Panamanian communities to use directly as food and as important components of traditional medicines and remedies. These uses are part of the traditional culture of both the Guna Indians and the Afro-Antillean communities. One driving force to better understand the biology of the various species of Gracilaria is their additional, commercial uses based on the agars they produce. In this study, we evaluated the effects of two commercial, soluble extract powders of the temperate, brown seaweed Ascophyllum nodosum (i.e., Ascophyllum marine plant extract powder—AMPEP), and one which had a boosted potassium level (designated as AMPEP K+). Each was evaluated for any micropropagation effects on the tropical red alga, Gracilaria blodgettii, in three independent experiments each of which lasted 45 days (the normal grow-out period). The phyco-stimulatory extracts were tested with and without association with standard plant growth regulators which are commonly used in micropropagation practices for higher plants. Growth was measured as a function of increased fresh weight and the number of newly emergent lateral shoots. This study demonstrated that vegetative propagules of G. blodgettii treated with AMPEP at 0.1 mg L−1 provided significant contributions to the successful and sustainable supply of vegetative propagules (“seedstock”). We suggest that the costs and quality of seedstock production can be significantly reduced over traditional methods, thereby contributing to the establishment of much-needed, viable marine farming practices in the Panamanian Caribbean.

Antioxidant and antibacterial activity of red seaweed Kappaphycus alvarezii against pathogenic bacteria

Seaweeds can produce variety of bioactive components for the benefits of humans. Malaysia is one of the countries to produce red seaweeds, which are popular secondary metabolites. Kappaphycus species, largest tropical red algae exhibit the high growth rate. It was reported that its biomass can grow double in just 15 to 30 days. Therefore, this investigation emphasized on two extraction methods such as hot water and ethanolic Soxhlet extraction to extract the bioactive compounds from Kappaphycus alvarezii. Both of theseextractions were screened to produce antimicrobial and antioxidants compounds. Total phenolic content and ferric reducing assays were employed to quantify antioxidant properties. Whereas, the disc diffusion assays were used to study antibacterial activity. The results reported the highest phenolic content for ethanolic extract (20.25 ± 0.03 mg gallic acid equivalents per gram of extract). On the other hand, the value of phenolic content was slightly decreased 19.1 ± 0.81 mg gallic acid equivalents per gram of extract for the hot water extract. It was also found that both the extracts were potentially capable of balancing reactive oxygen species. Disc diffusion assay results indicated that the extract of red alga K. alvarezi were more efficient against B. cereus. Among the fatty acids determined levoglucosenone and 4-Pyridinemethanol were present in high percentages in hot water extract whereas Hexamethyl- cyclotrisiloxane followed by 1, 2, 5- Thiadiazole-3-carboxamide, 4-[(2-chloroethyl) amino]-N-(2-hydroxyethyl) were present in ethanolic extract of K. alvarezi. The present study concluded that, hot water extracts of K. alvarezii can be used for large scale production of bioactive compounds utilizing an easily available potential seaweed. Future research of red seaweed will be highly important for pharmaceutical and medicinal field as well as a homogenizer in milk products, toothpaste and jellies in other industrial applications.

Inhibitory activities of three Malaysian edible seaweeds on lipase and α-amylase

Ethanol extracts, dried powders and fibres (total and soluble fibre) of the tropical red algae Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum were analysed for their effect on lipase and α-amylase activity using turbidimetric method and dinitrosalicylic acid (DNS) assay, respectively. The nutrient composition analyses were determined using standard methods. The ethanol extract of dried K. striatus (Ks-III) showed the highest reduction in lipase activity with 92 % inhibition followed by seaweed powders (K. alvarezii (Ka-III), K. striatus (Ks-III) and E. denticulatum (Ed-III)) with average inhibition of 60 %. Soluble fibres of K. alvarezii (Ka-V) and E. denticulatum (Ed-V) showed significant inhibition with 60 and 57 % reduction, respectively. Only the ethanol extract of fresh E. denticulatum (Ed-I) showed 88 % inhibition of α-amylase. Nutritional component analyses showed that all three seaweeds are low in crude fat, suggesting the possible use of seaweed as a dietary supplement and for potential weight and glycaemia management.

Marine Invasion in the Mediterranean Sea: The Role of Abiotic Factors When There Is No Biological Resistance

The tropical red alga Womersleyella setacea (Rhodomelaceae, Rhodophyta) is causing increasing concern in the Mediterranean Sea because of its invasive behavior. After its introduction it has colonized most Mediterranean areas, but the mechanism underlying its acclimatization and invasion process remains unknown. To understand this process, we decided i) to assess in situ the seasonal biomass and phenological patterns of populations inhabiting the Mediterranean Sea in relation to the main environmental factors, and ii) to experimentally determine if the tolerance of W. setacea to different light and temperature conditions can explain its colonization success, as well as its bathymetric distribution range. The bathymetric distribution, biomass, and phenology of W. setacea were studied at two localities, and related to irradiance and temperature values recorded in situ. Laboratory experiments were set up to study survival, growth and reproduction under contrasting light and temperature conditions in the short, mid, and long term.Results showed that, in the studied area, the bathymetric distribution of W. setacea is restricted to a depth belt between 25 and 40 m deep, reaching maximum biomass values (126 g dw m−2) at 30 m depth. In concordance, although in the short term W. setacea survived and grew in a large range of environmental conditions, its life requirements for the mid and long term were dim light levels and low temperatures. Biomass of Womersleyella setacea did not show any clear seasonal pattern, though minimum values were reported in spring. Reproductive structures were always absent. Bearing in mind that no herbivores feed on Womersleyella setacea and that its thermal preferences are more characteristic of temperate than of tropical seaweeds, low light (50 µmol photon m−2 s−1) and low temperature (12°C) levels are critical for W. setacea survival and growth, thus probably determining its spread and bathymetric distribution across the Mediterranean Sea.

Ichthyotoxic brominated diphenyl ethers from a mixed assemblage of a red alga and cyanobacterium: Structure clarification and biological properties

Primary fractions from the extract of a tropical red alga mixed with filamentous cyanobacteria, collected from Papua New Guinea, were active in a neurotoxicity assay. Bioassay-guided isolation led to two natural products ( 1, 2) with relatively potent calcium ion influx properties. The more prevalent of the neurotoxic compounds ( 1) was characterized by extensive NMR, mass spectrometry, and X-ray crystallography, and shown to be identical to a polybrominated diphenyl ether metabolite present in the literature, but reported with different NMR properties. To clarify this anomalous result, we synthesized a candidate isomeric polybrominated diphenyl ether ( 3), but this clearly had different NMR shifts than the reported compound. We conclude that the original isolate of 3,4,5-tribromo-2-(2,4-dibromophenoxy)phenol was contaminated with a minor compound, giving rise to the observed anomalous NMR shifts. The second and less abundant natural product ( 2) isolated in this study was a more highly brominated species. All three compounds showed a low micromolar ability to increase intracellular calcium ion concentrations in mouse neocortical neurons as well as toxicity to zebrafish. Because polybrominated diphenyl ethers have both natural as well as anthropomorphic origins, and accumulate in marine organisms at higher trophic level (mammals, fish, birds), these neurotoxic properties are of environmental significance and concern.

Probing marine natural product defenses with DESI-imaging mass spectrometry

To demonstrate that a toxin or other natural product serves as a predator or pathogen deterrent requires that (i) the defined compound in question have the requisite biological activity, (ii) the compound is present at levels capable of eliciting an effect in the target organism, (iii) there is a physical mechanism for the substance to interact with its target before death of the producer, and (iv) the avoidance behavior in the target organism actually occurs. Although many highly-unique natural products have been defined from the marine environment, and they appear to serve as predator and pathogen deterrents, it has been extremely challenging to establish their quantity and physical location in the producing organism's tissues, thus leaving uncertainty about their true natural function. However, in this issue of PNAS, Lane et al. (1) have used a novel mass spectrometric approach [desorption electrospray ionization (DESI)] (Fig. 1) to sensitively, yet precisely, measure the physical location and quantities of antifungal natural products in the surface tissues of a tropical red alga. This advance, combined with other analytical MS developments as described below, is allowing more definitive identification of the physical location of natural products within biological tissues, cells, or even complex mixed-species assemblages (2, 3) and represents a dramatic technological advance for studying such phenomena.

Growth and metabolic responses of the tropical red alga Gracilaria blodgettii Harvey under different abiotic factors

Growth and metabolic responses of the tropical red alga <i>Gracilaria blodgettii</i> Harvey under different abiotic factors

Comparison of TNT removal from seawater by three marine macroalgae

Axenic plantlets derived from three species of marine macroalgae, the temperate green alga Acrosiphonia coalita, the temperate red alga Porphyra yezoensis, and the tropical red alga Portieria hornemannii, all possessed a similar metabolic route to remove the explosive compound 2,4,6-trinitrotolune (TNT) from seawater. At a biomass density of 1.2 g l(-1) and initial TNT concentrations of 10 mg l(-1) or less, TNT removal from seawater was 100% within 72 h for P. hornemannii and P. yezoensis. Specific rate constants for TNT uptake were 0.016-0.018 l g(-1)FWh(-1) for A. coalita filaments, 0.047-0.062 l g(-1)FW h(-1) for P. yezoensis blades, and 0.037-0.049 l g(-1)FW h(-1) for P. hornemannii microplantlets. Only trace amounts of TNT were found within the biomass. All species reduced TNT to 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dintrotoluene, but these products never accounted for more than 20% of the initial TNT.

Different patterns of carotenoid composition and photosynthesis acclimation in two tropical red algae

To be able to survive, marine macroalgae in shallow coastal waters need mechanisms for short-term acclimation to fast changes in their environment. Of major importance are mechanisms that regulate the efficiency of photosynthesis by protecting PS II from photo-oxidative damage. Carotenoids, xanthophyll cycles and non-photochemical quenching (NPQ) are central constituents of such protection mechanisms. Red algae as a group do not have a universal carotenoid composition. We screened ten red algal species and selected two species, originating from similar ecological conditions but with different carotenoid compositions, for use in irradiance-acclimation experiments. We selected the tropical intertidal species Gracilaria domingensis and Kappaphycus alvarezii with antheraxanthin and lutein as major xanthophylls, respectively. Simultaneous in vivo fluorescence and O2 evolution experiments were performed at different irradiance levels, which allowed a direct comparison of overall photosynthetic performance with NPQ. Interconversions of xanthophylls (violaxanthin, zeaxanthin, β-cryptoxanthin and one unidentified carotenoid) did occur in G. domingensis, but not in response to sudden exposure to light. Thus, NPQ was not correlated with any xanthophyll cycle during short-term acclimation to light. G. domingensis had five times higher weight-specific photosynthetic rates than K. alvarezii, which can be explained by the thicker thallus of K. alvarezii. Chlorophyll-specific gross photosynthetic rates were higher in K. alvarezii, but net rates were the same for both species. G. domingensis showed an immediate strong onset of NPQ upon exposure to irradiance, followed by downregulation to the NPQ level required. In K. alvarezii NPQ increased slowly until the required NPQ level was reached. At high irradiance G. domingensis downregulated photosynthesis while K. alvarezii continued to produce O2 even at 2,000 μmol photons m−2 s−1 without NPQ increase. The strategy of K. alvarezii may provide short-term gains but with the risk of oxidative damage. The fast onset of NPQ in G. domingensis even at subsaturating irradiance as well as downregulation of photosynthesis when NPQ is saturated might provide this species with a competitive advantage under conditions of changing irradiance in the field.

CIRCADIAN RHYTHM OF PHOTOSYNTHETIC OXYGEN EVOLUTION IN KAPPAPHYCUS ALVAREZII (RHODOPHYTA): DEPENDENCE ON LIGHT QUANTITY AND QUALITY

The rate of oxygen evolution of the tropical red alga Kappaphycus alvarezii (Doty) Doty was measured for 6 days in the laboratory using a computer‐aided method for long‐term recording. In cool white light, Kappaphycus exhibited a robust circadian rhythm of O2 evolution in the irradiance range of 100 to 1000 μmol photons·m−2·s−1. With increasing irradiance, the period of the free‐running rhythm, τ, decreased in blue and increased in red light but did not change significantly in green light. The accelerating or slowing action of blue or red light, respectively, points to two photoreceptors used in the light transduction pathway of the circadian oscillator controlling oxygen evolution or the light reactions of photosynthesis in Kappaphycus. No significant changes of τ were observed with increasing irradiance in cool white light, possibly due to the additive opposing responses caused by blue and red light.

Isolation of the chlorophyll-related pigment isochlorin-e 4 from the tropical red alga Dasya pedicellata

Isochlorin-e 4, a blue-green pigment related to the chlorophylls, has been isolated as a major metabolite from the tropical marine red alga Dasya pedicellata. The structure of isochlorin-e 4 was assigned on the basis of comprehensive 2D 13C and 1H NMR analyses. Although isochlorin-e 4 has been prepared by synthesis, this appears to be the first report of its occurrence in nature.

A Partially Pyruvated Carrageenan from Hawaiian Grateloupia filicina (Cryptonemiales, Rhodophyta)

Interest in the farming and utilization of seaweeds has increased and the search for a possible source of lambda carrageenan among tropical red algae has led to this investigation of the polysaccharide of G. filicina

Chemical defense in the seaweed Ochtodes secundiramea (Montagne) Howe (Rhodophyta): effects of its monoterpenoid components upon diverse coral-reef herbivores

Many species of tropical red algae are known to produce halogenated secondary metabolites that have been hypothesized to function in chemical defense. The tropical fleshy red alga Ochtodes secundiramea (Montagne) Howe is a typical example known to produce the halogenated monoterpenoids ochtodene and chondrocole A. In this study, the susceptibility of O. secundiramea to grazing by herbivorous fishes was examined by offering an array of 11 red, green, and brown seaweeds to herbivores in field assays in the Grenadine Islands of the Caribbean. O. secundiramea was among the least susceptible to grazers, with no transplants being lost to herbivory during our assay. To examine the possible roles of the monoterpenoids in reducing herbivory, the metabolites ochtodene and chondrocole C were isolated and purified by high-performance liquid chromatography (HPLC). These monoterpenoids were tested in field assays for their feeding deterrent effects toward herbivorous fishes in the Grenadine Islands and on Guam in the tropical western Pacific. In both sets of experiments, ochtodene was an effective feeding deterrent and chondrocole C was not. These compounds, and a nonpolar mixture (more than three compounds) of halogenated monoterpenes from Ochtodes, were also tested for their feeding deterrent effects toward herbivorous amphipods collected in the Grenadine Islands. Only the unresolved monoterpene mixture was an effective feeding deterrent toward the amphipods. Herbivory on coral reefs is intense and the diversity of herbivore types is great. It appears that the variety of secondary metabolites synthesized by seaweeds such as O. secundiramea may be effective in deterring different reef herbivores.

Chemical Defense Against Diverse Coral-Reef Herbivores.

Five secondary metabolites from tropical marine algae and one related compound from an herbivorous sea-hare (Aplysidae) were coated, at approximately natural concentrations, onto the palatable seagrass Thalassia testudinum and placed on coral reefs where they could be eaten by the diverse group of herbivorous fishes that occur there. Laboratory feeding assays with the herbivorous sea urchin Diadema antillarum were also conducted. When compared to appropriate controls, the following terpenoid compounds significantly reduced the amount of Thalassia eaten by both Diadema and reef fishes: stypotriol, from the brown seaweed Stypopodium zonale; pachydictyol-A, which is produced by several genera of tropical (Dictyota and Dilophus) and warm-temperate (Pachydictyon and Glossophora) brown seaweeds; elatol, from the tropical red alga Laurencia obtusa; and isolaurinterol, which is produced by several tropical and warm-temperate species of Laurencia. Under very mild acid conditions, isolaurinterol is converted to a structurally similar compound, aplysin, found in high concentrations in sea-hares that feed on isolaurinterol-containing Laurencia species. Aplysin did not deter feeding by either type of herbivore. Cymopol, a terpenoid bromohydroquinone from the green alga Cymopolia barbata, significantly reduced feeding by reef fishes but significantly stimulated feeding by Diadema. Pharmacological and crude bioactivity tests suggest that several of these compounds function as generalized toxins. However, these generalized laboratory assays are not necessarily good predictors of how compounds will affect feeding by herbivores. For example, pachydictyol-A and stypotroil were equally effective at deterring fishes and Diadema, even though pachydictyol-A shows almost no bioactivity in laboratory assays while stypotriol and its oxidation product, stypoldione, are very bioactive. Herbivory on coral reefs is more intense than in any other habitat studied and the diversity of herbivore types is high. It appears that this intense grazing has provided strong selection for seaweeds that synthesize unique secondary metabolites that significantly reduce the consumption of plants exposed to attack by a diverse group of reef herbivores.

Two New Chamigrene Sesquiterpenoids from the Tropical Red Alga Laurencia obtusa

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo New Chamigrene Sesquiterpenoids from the Tropical Red Alga Laurencia obtusaWilliam H. Gerwick, Albert Lopez, Ramon Davila, and Richard AlborsCite this: J. Nat. Prod. 1987, 50, 6, 1131–1135Publication Date (Print):November 1, 1987Publication History Published online1 July 2004Published inissue 1 November 1987https://doi.org/10.1021/np50054a020RIGHTS & PERMISSIONSArticle Views181Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (291 KB) Get e-Alerts Get e-Alerts

Palisadins A,B and related monocyclofarnesol-derived sesquiterpenoids from the red marine alga [formula omitted] cf. [formula omitted

Five new monocyclofarnesol-derived sesquiterpenoids, along with the previously reported lactone aplysistatin, have been isolated from the tropical red alga Laurencia cf. palisada . The structures of these new compounds were defined by spectral and chemical analyses, including their partial interconversion with aplysistatin.