Search Results (15)

Brown algae (Phaeophyceae) play vital ecological roles in marine ecosystems and are important models for studying organelle genome evolution. Despite their significance, mitogenome data for many taxa remain limited. In this study, we present the complete mitogenome sequence of Dictyota coriacea, a representative brown alga from the family Dictyotaceae (Phaeophyceae). The circular mitogenome of D. coriacea is 31,573 bp in length and encodes 62 genes, including 35 protein-coding genes (PCGs; including uncharacterized open reading frame (orf109)), 25 tRNAs, and 3 rRNAs. The overall gene content and arrangement are largely conserved and consistent with other Dictyotaceae species. However, minor but notable genomic variations were observed, such as gene overlaps, variation in gene lengths, and differences in tRNA gene copy numbers, and the absence of rpl31. All PCGs use standard start and stop codons, with most initiating with ATG and terminating with TAA, TAG, or TGA. Phylogenetic analysis confirmed D. coriacea’s close relationship with D. dichotoma, Dictyopteris divaricata, and Dictyotopsis propagulifera, supporting its taxonomic placement. This study’s findings improve our understanding of algae evolution and provide useful genetic markers for future research on evolutionary relationships and species classification within this group of algae. Full article

Macroalgae (seaweeds) represent a sustainable and alternative source of high-value fatty acids (FAs), including omega-3 (n-3) and omega-6 (n-6), which could help alleviate pressure on wild fish stocks and mitigate global overfishing. This study analyzed the FA composition of field-collected red (Chondracanthus acicularis, Ballia callitriche, Gracilaria sp., and Gelidium coulteri), brown (Padina pavonica, Sargassum vulgare, Cystoseira myrica, Cystoseira sp., Dictyota dichotoma, and Stephanocystis mundane), and green seaweeds (Ulva compressa). Additionally, lipid extraction was optimized using food-grade solvents, reaction temperatures, and the functional properties of selected green and brown seaweeds. The results showed that brown and green seaweeds contained higher total FA content than red seaweeds, with a favorable n-6/n-3 ratio below 10. The selected species’ functional properties (Water- and Oil-Holding Capacities, Swelling Capacity) met food-grade standards. Ethyl acetate at 60 °C was identified as the optimal food-grade solvent for lipid extraction. Functional properties varied significantly by species and processing conditions, with Ulva compressa exhibiting superior Water- and Oil-Holding Capacities and Swelling Capacity compared to Cystoseira myrica, highlighting its potential as a functional food ingredient. These findings support using seaweeds as a sustainable source for human nutrition. Full article

Marine algae are renowned for their health benefits due to the presence of functional bioactive compounds. In this context, this study aims to valorize the extract of a seaweed, Dictyota dichotoma (D. dichotoma), through phytochemical characterization using liquid chromatography–mass spectrometry (HPLC-MS), as well as in vitro and in silico evaluation of its biological activities (antioxidant and antimicrobial). Phytochemical characterization revealed that the ethanolic extract of Dictyota dichotoma (DdEx) is rich in phenolic compounds, with a total of 22 phycocompounds identified. Antioxidant activity, measured by various methods, showed an IC₅₀ of 120 µg/mL for the DPPH assay, an EC₅₀ of 120.53 µg/mL for the FRAP assay, and a total antioxidant power of 685.26 µg AAE/mg according to the phosphomolybdate (TAC) method. Evaluation of antibacterial activity showed a zone of inhibition diameter ranging from 11.93 to 22.58 mm, with the largest zone observed for the Escherichia coli (E. coli) strain. For antifungal activity, inhibition zone diameters ranged from 22.38 to 23.52 mm, with the largest recorded for the Saccharomyces cerevisiae (S. cerevisiae) strain. The in silico study identified tetragalloyl-glucose, apigenin-7-O-glucoside, and pentagalloyl-glucose as the most active compounds against NADPH oxidase, with docking scores of −7.723, −7.424, and −6.402 kcal/mol, respectively. Regarding antibacterial activity, apigenin-7-O-glucoside, pelargonidin-3-O-glucoside, and secoisolariciresinol demonstrated high affinity for E. coli beta-ketoacyl-[acyl carrier protein] synthase, with docking scores of −7.276, −6.811, and −6.594 kcal/mol, respectively. These in vitro and in silico evaluations showed that D. dichotoma extract possesses antioxidant and antimicrobial properties, due to its richness in bioactive compounds identified by HPLC. Full article

The main goal of this study was to assess the bioactive and polysaccharide compositions, along with the antioxidant and antibacterial potentials, of five seaweeds collected from the northeastern coast of Algeria. Through Fourier transform infrared spectroscopy analysis and X-ray fluorescence spectroscopy, the study investigated the elemental composition of these seaweeds and their chemical structure. In addition, this study compared and identified the biochemical makeup of the collected seaweed by using cutting-edge methods like tandem mass spectrometry and ultra-high-performance liquid chromatography, and it searched for new sources of nutritionally valuable compounds. According to the study’s findings, Sargassum muticum contains the highest levels of extractable bioactive compounds, showing a phenolic compound content of 235.67 ± 1.13 µg GAE·mg⁻¹ and a total sugar content of 46.43 ± 0.12% DW. Both S. muticum and Dictyota dichotoma have high concentrations of good polyphenols, such as vanillin and chrysin. Another characteristic that sets brown algae apart is their composition. It showed that Cladophora laetevirens has an extracted bioactive compound content of 12.07% and a high capacity to scavenge ABTS⁺ radicals with a value of 78.65 ± 0.96 µg·mL⁻¹, indicating high antioxidant activity. In terms of antibacterial activity, S. muticum seaweed showed excellent growth inhibition. In conclusion, all five species of seaweed under investigation exhibited unique strengths, highlighting the variety of advantageous characteristics of these seaweeds, especially S. muticum. Full article

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05–1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity. Full article

Seaweed has been known to possess beneficial effects forhuman health due to the presence of functional bioactive components. The n-butanol and ethyl acetate extracts of Dictyota dichotoma showed ash (31.78%), crude fat (18.93%), crude protein (14.5%), and carbohydrate (12.35%) contents. About 19 compounds were identified in the n-butanol extract, primarily undecane, cetylic acid, hexadecenoic acid, Z-11-, lageracetal, dodecane, and tridecane, whereas 25 compounds were identified in the ethyl acetate extract, mainly tetradecanoic, hexadecenoic acid, Z-11-, undecane, and myristic acid. FT-IR spectroscopy confirmed the presence of carboxylic acid, phenols, aromatics, ethers, amides, sulfonates, and ketones. Moreover, total phenolic contents (TPC) and total flavonoid contents (TFC) in ethyl acetate extract were 2.56 and 2.51 mg GAE/g and in n-butanol extract were 2.11 and 2.25 mg QE/g, respectively. Ethyl acetate and n-butanol extracts at a high concentration of 100 mg mL⁻¹ showed 66.64 and 56.56 % inhibition of DPPH, respectively. Antimicrobial activity revealed that Candida albicans was the most susceptible microorganism, followed by Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, whereas Pseudomonas aeruginosa showed the least inhibition at all concentrations. The in vivo hypoglycemic study revealed that both extracts exhibited concentration-dependent hypoglycemic activities. In conclusion, this macroalgae exhibited antioxidant, antimicrobial, and hypoglycemic potentials. Full article

The marine environment has a significant impact on life on Earth. Organisms residing in it are vital for the ecosystem but also serve as an inexhaustible source of biologically active compounds. Herein, the biodiversity of two brown seaweeds, Dictyota dichotoma and Dictyota fasciola from the Adriatic Sea, was evaluated. The aim of the study was the determination of differences in compound composition while comparing their activities, including antioxidant, antimicrobial, and enzyme inhibition, in connection to human digestion, dermatology, and neurological disorders. Chemical analysis revealed several terpenoids and steroids as dominant molecules, while fucoxanthin was the main identified pigment in both algae. D. dichotoma had higher protein, carbohydrate, and pigment content. Omega-6 and omega-3 fatty acids were identified, with the highest amount of dihomo-γ-linolenic acid and α-linolenic acid in D. dichotoma. Antimicrobial testing revealed a dose-dependent inhibitory activity of methanolic fraction against Escherichia coli and Staphylococcus aureus. Moderate antioxidant activity was observed for both algae fractions, while the dietary potential was high, especially for the D. fasciola dichloromethane fraction, with inhibition percentages of around 92% for α-amylase and 57% for pancreatic lipase at 0.25 mg/mL. These results suggest that Dictyota species might be a potent source of naturally derived agents for obesity and diabetes. Full article

The content of bioactive compounds in four brown and one red algae from the Adriatic Sea (Dictyota dichotoma, Gongolaria barbata, Ericaria amentacea, Sargassum hornschuchii and Ellisolandia elongata) is explored. The efficiency of two different extraction methods viz. ultrasound-assisted extraction (UAE) and matrix solid-phase dispersion (MSPD) to obtain the extracts rich in phenolic compounds was compared. The effect of the extraction solvent to modulate the phenolic profile was assessed. In general, the mixture ethanol/water in an isovolumetric proportion showed the best results. The total phenolic content (TPC) and antioxidant activity (AA), as well as the individual polyphenolic profile, were evaluated for five target algae. TPC values ranged between 0.2 mg GAE/g (for E. elongata) and 38 mg GAE/g (for S. hornschuchii). Regarding the quantification of individual polyphenols by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the presence of a high number of hydroxybenzoic acid derivatives (mainly of 3- and 4-hydroxybenzoic acids) in all species was noted. In G. barbata their concentrations reached up to 500 mg/kg. IC₅₀ values (ABTS assay) ranged between 44 mg/L (for S. hornschuchii) and 11,040 mg/L (for E. elongata). This work contributes to the in-depth characterization of these little-explored algae, showing their potential as a natural source of phenolic compounds. Full article

The search for new sources of antimicrobial compounds has become an urgent need, due to the threat that the spread of bacterial resistance represents for global health and food safety. Brown macroalgae have been proposed as a great reservoir in the search for novel antimicrobial compounds. In this study, mid-polarity extracts were performed with a selection of 20 brown macroalgae species from northern Spain. The total polyphenol, carbohydrate and protein contents were quantified by spectrophotometry. The volatile organic compounds (VOCs) of whole macroalgae were also studied as a biomarker of their metabolic state in the representative species of the tested families by gas chromatography-mass spectrometry (GC-MS). The antimicrobial potential of the extracts was assessed by a disk diffusion assay against 20 target bacteria and further determinations of the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were performed by a microdilution assay for the active extracts. Ericaria selaginoides, Bifurcaria bifurcata and Dictyota dichotoma showed an antimicrobial effect against six Gram-positive strains: Bacillus cereus, Bacillus subtilis, Geobacillus stearothermophilus, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus haemolyticus. The phenolic content was generally higher in the extracts that showed antimicrobial activity, followed by carbohydrates and low contents of proteins. The results obtained in this study reveal the potential of brown macroalgae as a promising alternative source of antimicrobial compounds as functional ingredients for the application in industrial fields. Full article

Dictyotaceae, the large family of brown algae with the genus Dictyota as the richest one among them, produce a significant number of secondary metabolites, like diterpenes. The aim of this study was to investigate the variations in the composition of the volatile organic compounds (VOCs) of the brown alga Dictyota dichotoma collected from the Adriatic Sea. For the first time, both seasonal changes and the impact of air drying were examined. Headspace solid-phase microextraction (HS-SPME) on two fibres with different polarities and hydrodistillation (HD), followed by gas chromatography and mass spectrometry (GC-MS) analysis, was performed on both fresh (FrDd) and air-dried (DrDd) D. dichotoma. The major compounds of HS-FrDd were pentadecane and oct-1-en-3-ol. The percentage of pentadecane in HS-DrDd was increased up to 7.8 times in comparison with HS-FrDd. Principal component analysis (PCA) identified differences between the variability of data among fresh and dried samples over months and clearly dissociated the fresh May samples from the others in the HS-SPME results. The most abundant group of VOCs in HD were terpenes, with diterpenes isopachydictyol A and cembra-4,7,11,15-tetraen-3-ol as the major compounds. Diterpene pachydictyol A was also found and among sesquiterpenes and gleenol was the most abundant. Based on the dominant compound analyses, the PCA showed distinct separation of the fresh and dried samples, indicating similarities between the samples and allowing the establishment of typical VOCs significant for the chemotaxonomy of D. dichotoma. Full article

Malaysia has a long coastline surrounded by various islands, including North Borneo, that provide a suitable environment for the growth of diverse species of seaweeds. Some of the important North Bornean seaweed species are Kappaphycus alvarezii, Eucheuma denticulatum, Halymenia durvillaei (Rhodophyta), Caulerpa lentillifera, Caulerpa racemosa (Chlorophyta), Dictyota dichotoma and Sargassum polycystum (Ochrophyta). This review aims to highlight the therapeutic potential of North Bornean seaweeds and their nutraceutical profiling. North Bornean seaweeds have demonstrated anti-inflammatory, antioxidant, antimicrobial, anticancer, cardiovascular protective, neuroprotective, renal protective and hepatic protective potentials. The protective roles of the seaweeds might be due to the presence of a wide variety of nutraceuticals, including phthalic anhydride, 3,4-ethylenedioxythiophene, 2-pentylthiophene, furoic acid (K. alvarezii), eicosapentaenoic acid, palmitoleic acid, fucoxanthin, β-carotene (E. denticulatum), eucalyptol, oleic acid, dodecanal, pentadecane (H. durvillaei), canthaxanthin, oleic acid, pentadecanoic acid, eicosane (C. lentillifera), pseudoephedrine, palmitic acid, monocaprin (C. racemosa), dictyohydroperoxide, squalene, fucosterol, saringosterol (D. dichotoma), and lutein, neophytadiene, cholest-4-en-3-one and cis-vaccenic acid (S. polycystum). Extensive studies on the seaweed isolates are highly recommended to understand their bioactivity and mechanisms of action, while highlighting their commercialization potential. Full article

In this study, the influences of temperature (20, 40 and 60 °C) and extraction solvents (water, ethanol) on the ultrasound-assisted extraction of phenolics from the Adriatic macroalgae Dictyota dichotoma and Padina pavonica were studied. The extracts were analysed for major phenolic sub-groups (total phenolics, flavonoids and tannins) using spectrometric methods, while the individual phenolics were detected by HPLC. The antioxidant activities were evaluated using three methods: Ferric Reducing/Antioxidant Power (FRAP), scavenging of the stabile 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and Oxygen Radical Antioxidant Capacity (ORAC). The aim of the study was also to find the connection between the chemical composition of the extracts and their biological activity. Therefore, principal component analysis (PCA), which permits simple representation of different sample data and better visualisation of their correlations, was used. Higher extraction yields of the total phenolics, flavonoids and tannins were obtained using an alcoholic solvent, while a general conclusion about the applied temperature was not established. These extracts also showed good antioxidant activity, especially D. dichotoma extracts, with high reducing capacity (690–792 mM TE) and ORAC values (38.7–40.8 mM TE in 400-fold diluted extracts). The PCA pointed out the significant influence of flavonoids and tannins on the investigated properties. The results of this investigation could be interesting for future studies dealing with the application of these two algae in foods, cosmetics and pharmaceuticals. Full article

Plant volatile organic compounds (VOCs) represent a relatively wide class of secondary metabolites. The VOC profiles of seven seaweeds (Grateloupia filicina, Polysiphonia senticulosa, Callithamnion corymbosum, Sargassum thunbergii, Dictyota dichotoma, Enteromorpha prolifera and Ulva lactuca) from the Yellow Sea of China were investigated using multifiber headspace solid phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC–MS), among them, the VOCs of three red algae Grateloupia filicina, Polysiphonia senticulosa, and Callithamnion corymbosum were first reported. Principal component analysis (PCA) was used to disclose characteristic categories and molecules of VOCs and network pharmacology was performed to predict potential biomedical utilization of candidate seaweeds. Aldehyde was found to be the most abundant VOC category in the present study and (E)-β-ionone was the only compound found to exist in all seven seaweeds. The chemical diversity of aldehydes in E. prolifera suggest its potential application in chemotaxonomy and hinted that divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber is more suitable for aldehyde extraction. VOCs in D. dichotoma were characterized as sesquiterpenes and diterpenes and the most relevant pharmacological pathway was the neuroactive ligand–receptor interaction pathway, which suggests that D. dichotoma may have certain preventive and therapeutic values in cancer, especially in lung cancer, in addition to neuropsychiatric diseases. Full article

Marine organisms are potentially prolific sources of high qualify fatty acids that represent useful leads in the development of new nutraceutical agents. In this work, we investigated the lipid composition of six algae species from the Northwest of Spain (Ulva intestinalis, Ulva lactuca, Fucus vesiculosus, Dictyota dichotoma, Cystoseira baccata and Himanthalia elongata) and compared the antioxidant and antibacterial activity of ethanolic extracts obtained by pressurized liquid extraction (PLE). Furthermore, Fucus vesiculosus (F. vesiculosus) PLE using five solvents of different polarities (hexane, ethyl acetate, acetone, ethanol and ethanol:water 50:50) at three temperatures (80 °C, 120 °C and 160 °C) was investigated. F. vesiculosus ethanolic PLE extract presents considerably higher capacity of inhibiting 50% of DPPH (1,1-diphenyl-2-picryl hydrazyl) (IC₅₀ = 7.17 μg/mL) in comparison with the rest of macroalgae studied. Moreover, the potential antimicrobial activity tested on E. coli and S. aureus shows that F. vesiculosus extract produced the best inhibition (IC₅₀ was 2.24 mg/mL (E. coli) and 1.27 mg/mL (S. aureus)). Furthermore, regarding the different solvents and temperatures used to investigate F. vesiculosus PLE, results showed that this technique using ethyl acetate is a selective method to enrich long chain fatty acids (oleic acid, arachidonic acid and eicosapentaenoic acid) with ω-6/ω-3 ratios close to 2.7. Full article

Two new diterpenoids, pachydictyol B (1a/1b) and C (2), were isolated from the dichloromethane extract of the marine brown alga, Dictyota dichotoma, collected from the Red Sea coast of Egypt, along with the known metabolites, pachydictyol A (3a), dictyol E (4), cis-africanan-1α-ol (5a), fucosterol (6), tetrahydrothiophen-1,1-dioxide and poly-β-hydroxybutyric acid. GC-MS analysis of the nonpolar fractions also indicated the presence of β-bourbonene and nonanal, along with three hydrocarbons and five fatty acids or their simple derivatives, respectively. GC-MS analysis of the unsaponifiable algal petroleum ether extract revealed the presence of a further eight compounds, among them 2,2,6,7-tetramethyl-10-oxatricyclo[4.3.0.1(1,7)]decan-5-one (7), N-(4-bromo-n-butyl)-pipe ridin-2-one (8) and tert-hexadecanethiol. Structures 1–6 were assigned by 1D and 2D NMR, mass spectra (EI, CI, HREI and HRESI) and by comparison with data from related structures. The crude algal extract was potently active against the breast carcinoma tumor cell line, MCF7 (IC₅₀ = 0.6 µg mL⁻¹); pachydictyol B (1a) and dictyol E (4) showed weak antimicrobial properties, and the other compounds were inactive. Pachydictyols B (1a) and C (2) demonstrated a weak and unselective cytotoxicity against twelve human tumor cell lines with a mean IC₅₀ of >30.0 µM. Full article