Padina Boryana Research Articles

Marine macroalgae and their associated bacterial communities affect larval settlement and survivorship of the coral Pocillopora damicornis

Macroalgae play crucial roles as major habitat-forming organisms in marine ecosystems, having significant impacts on coral recruitment and reef recovery. However, the interactions between marine macroalgae and coral larvae remain poorly understood. Furthermore, little is known whether differences in bacterial assemblages associated with macroalgae may play roles in this process. Here, we comprehensively investigated the impacts of different macroalgae and their associated microbiomes on larval settlement and survival of coral Pocillopora damicornis. The results revealed significant variations in larval settlement and survival rates when exposed to different macroalgal species. The highest settlement rate, reaching 90%, was observed in the presence of the red alga Hypnea pannosa, followed by green algae Caulerpa serrulata, C. racemosa, and brown algae Turbinaria gracilis, Sargassum polycystum. Correspondingly, similarities in bacterial compositions were observed between H. pannosa and C. racemosa, as well as between T. gracilis and S. polycystum, implying associated bacterial may be related with the algal functions. Furthermore, macroalgae that facilitate larval settlement exhibited higher abundances of amplicon sequence variants (ASVs) associated with the metabolism of dimethylsulfoniopropionate or the antagonism of known coral pathogens. However, the brown alga Padina boryana failed to induce larval settlement with survival rate of zero after 120 h. The algal species harbored more abundances of ASVs related to Rhizobiaceae. These findings highlight the significant impact of macroalgae and their associated microbiomes on coral recruitment, as they influence both larval settlement and survival rates.

Efficacy of aqueous and alcoholic formulations extracted from Padina boryana algae against Aedes aegypti mosquito larvae: A comparative study

AbstractAedes aegypti is a mosquito species known for transmitting several diseases, with dengue fever being of utmost importance. Controlling the spread of dengue fever remains a significant global health challenge. Other diseases transmitted by Ae. aegypti include Zika virus, chikungunya, and yellow fever. Padina boryana algae were collected from the Red Sea coast south of Jeddah to evaluate the effectiveness of its alcoholic and aqueous extracts against Ae. aegypti mosquito larvae. The algae sample was washed, dried in the shade, processed, and subjected to aqueous and alcohol extraction using a rotary evaporator. The resulting extracts were tested for their larvicidal activity against Ae. aegypti mosquito larvae using standard bioassay techniques. The larval mortality rates were recorded, and the lethal concentration (LC50 and LC90) values were calculated.The results revealed that both the aqueous and alcoholic extracts of P. boryana algae exhibited significant larvicidal activity against Ae. aegypti mosquito larvae. However, the alcoholic formulation demonstrated higher efficacy compared to the aqueous formulation. The LC50 values for the alcoholic and aqueous extracts were 194.8 and 195.7 ppm, respectively. The LC90 values for both extracts were 653.1 and 656.7 ppm, respectively. This indicates the effectiveness of Padina extracts as an effective pesticide against the larvae of the Ae. aegypti mosquito. Overall, the alcohol extract showed promising efficacy, indicating its potential as a significant component in developing effective mosquito control strategies.

Evaluation of Antibiofilm and Antiquorum Sensing Activities of Fucoidan Characterized from Padina boryana against Nosocomial Pathogens.

Modern functional chemicals that can be employed in biotechnology, pharmaceutics, and food science are a sustainable source to be found in seaweeds. The bioactivity of the majority of these marine compounds has received scant research. Fucoidan is a highly sulfated polysaccharide with a range of bioactivities, including an antipathogenic effect. There is still much to learn about the relationship between fucoidan structure and its function in pathogen infections. By employing microwave and probe sonication to create crude fucoidan, DEAE-cellulose anion-exchange chromatography was used to further purify the substance. Purified fucoidan was structurally characterized using UV-Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and NMR analysis. The results of the structural analysis demonstrate that sulfates and hydroxyl groups are present in the isolated fucoidan. There are fucose residues, according to the NMR data. The present study investigates the bioactivity of fucoidan, a polysaccharide derived from the brown algae Padina boryana, as a potent weapon against the known nosocomial diseases Proteus vulgaris and Salmonella enterica. Fluorescence microscopy was used to show that fucoidan antibiofilm action is totally effective against Proteus vulgaris and Salmonella enterica biofilm formations as well as planktonic cell growths at dosages over 25g/mL. Here, using in vitro investigations of the possible inactivation of molecules that are regulated by acyl-homoserine lactone (AHL) in both bacterial species, we explore the antiquarum sensing and antibiofilm capabilities of fucoidan. According to the present study, extracted fucoidan from Padina boryana can be used to generate antibacterial compounds and operate as a quorum-sensing inhibitor to combat side effects and antibiotic resistance.

Protective effect of the brown seaweed Padina boryana against UVB-induced photoaging in vitro in skin cells and in vivo in zebrafish

The ethanol extract of Padina boryana (PB-EtOH) containing phlorotannin effectively inhibits oxidative stress and melanin synthesis, suggesting the potential use of PB-EtOH in the cosmetics industry. To further investigate the cosmetic effects of PB-EtOH, its photoprotective effects against ultraviolet (UV) irradiation was investigated. The results displayed that PB-EtOH remarkably improved cell viability by suppressing the apoptosis via cleaning the intracellular reactive oxygen species (ROS) in UVB-exposed human keratinocytes. In addition, PB-EtOH effectively suppressed oxidative stress, increased collagen synthesis, and reduced the matrix metalloproteinase production in UVB-exposed human dermal fibroblasts in a concentration-dependent manner. Furthermore, the in vivo anti-photoaging effect was determined using the zebrafish model. The results displayed that PB-EtOH remarkably attenuated UVB-stimulated photodamage. The photoprotective effect was displays in reducing the levels of ROS, nitric oxide, lipid peroxidation, and cell death. These results demonstrate that PB-EtOH possesses anti-photoaging effects and suggest that PB-EtOH may be an ideal ingredient to develop a skincare product in the cosmetic industry.

Anti-Melanogenesis and Anti-Photoaging Effects of the Sulfated Polysaccharides Isolated from the Brown Seaweed Padina boryana.

Sulfated polysaccharides isolated from seaweeds are thought of as ideal ingredients in the pharmaceutical, nutraceutical, and cosmetics industries. Our previous study isolated and characterized sulfated polysaccharides from Padina boryana. The sulfated polysaccharides of Padina boryana (PBP) were extracted, and the antioxidant activity of PBP was evaluated. The results indicate that PBP possesses antioxidant effects and potential in the cosmetic industry. To further investigate the potential of PBP in cosmetics, the photoprotective and anti-melanogenesis effects of PBP were evaluated. The anti-melanogenesis test results display that PBP reduced the melanin content in the murine melanoma cells stimulated by alpha melanocyte-stimulating hormone from 203.7% to 183.64%, 144.63%, and 127.57% at concentrations of 25 μg/mL, 50 μg/mL, and 100 μg/mL, respectively. The anti-photodamage test results showed that PBP significantly protected skin cells against UVB-stimulated photodamage. PBP suppressed human epidermal keratinocyte (HaCaT cell) death by inhibiting apoptosis and reducing the level of intracellular reactive oxygen species. The intracellular reactive oxygen species level of HaCaT cells irradiated by UVB was reduced from 192.67% to 181.22%, 170.25%, and 160.48% by 25 μg/mL, 50 μg/mL, and 100 μg/mL PBP, respectively. In addition, PBP remarkably reduced UVB-induced human dermal fibroblast damage by suppressing oxidative damage, inhibiting collagen degradation, and attenuating inflammatory responses. These results indicate that PBP possesses photoprotective and anti-melanogenesis activities and suggest that PBP is a potential ingredient in the cosmetic industry.

Larvicidal effects of some natural products on the Aedes aegypti mosquito, a vector of dengue fever and Zika virus

AbstractNatural products are considered a good choice in the biological control of mosquitoes because they are an effective way to eliminate larvae and prevent an increase in mosquito numbers, while simultaneously not polluting the environment or damaging health. This investigation was designed to study the potential toxicity of three species of algae, Caulerpa racemosa (Weber‐van Bosse, 1909), Padina boryana (Thivy, 1966), and Turbinaria ornata (Turner J. Agardh, 1848), on the larvae of Aedes aegypti mosquito, the vector of dengue and Zika viruses. Among the studied species, Caulerpa racemosa showed the greatest effectiveness in eradicating A. aegypti larvae with an LC50 = 43.5 ppm, followed by Padina boryana with an LC50 = 51.93 ppm. Both species proved to be excellent candidates as a source of larvicidal agents and could be used commercially in mosquito control programs as eco‐friendly biopesticides. The combined activity of different mixtures against mosquito larvae was expressed as the coeffective factor (C.F.). C.F. values showed that the joint activity of insect growth regulator Dudim in combination with Caulerpa racemosa and Padina boryana extracts produced degrees of potentiation effects and degrees of additive effects were obtained with Dudim in combination with Turbinaria ornata extract.

Herbivory effects of sea urchin species on a coral reef (Bora-Bora, French Polynesia)

Macroalgae are becoming dominant on coral reefs worldwide, replacing corals as key habitat formers. Incrementing consumption rates by herbivores, such as sea urchins, has been identified as a viable strategy for promoting coral recovery. By means of a 28-day experiment, we assessed the grazing effects of the sea urchins, Tripneustes gratilla and Diadema setosum, on the macroalgal assemblages of shallow reefs at Bora-Bora (French Polynesia). In particular, each urchin species was either absent or maintained, using cages (n = 10), at a density of 5 individuals/m2. T. gratilla exerted stronger negative effects than D. setosum on all the examined macroalgae (i.e., Turbinaria ornata, Padina boryana, Halimeda spp, Dictyota spp). In addition, the grazing effects by T. gratilla on macroalgae emerged shortly after the start of the experiment, more rapidly than those of D. setosum. Despite an apparent lower food preference for T. ornata in D.setosum, all macroalgae were consumed by both species and the composition of the macroalgal assemblages (i.e., the proportion of each species) did not change after 28 days. Overall, our study suggests that herbivorous sea urchins, when at relatively high densities, could contribute to sustaining coral-dominance on coral reefs by keeping macroalgae under control.

Predicting macroalgal species distributions along the Thai-Malay Peninsula

The Thai-Malay Peninsula separates the tropical Western Indo-Pacific from the Central Indo-Pacific marine biogeographic realm and has been hypothesized to form a dispersal barrier between them. In this study we assessed the potential distribution of five common macroalgal species (i.e., Halimeda macroloba, Padina boryana, Padina sp., Sargassum plagiophyllum, and S. polycystum) in the region using species distribution models. Presence data was collected from field observations and literature from the last twenty years. Five presence-absence model algorithms with twenty environmental variables were used. The model ensembles were projected across the space to predict potential distributions of each species. The potential distribution of H. macroloba, P. boryana and Padina sp. approximated the observed distribution of the species with few areas of high probability of occurrence where species were not collected. The potential distributions of S. plagiophyllum and S. polycystum are clearly separated, except in Phuket Island where the two species were observed to occur in sympatry. Each species distribution model was mainly influenced by three or four environmental variables. Bathymetry and mean sea surface temperature were found to be the most important variables in, respectively, four and three species models. This study contributes towards understanding the current distribution patterns of five ecologically important seaweeds and may contribute to studies predicting the impact of climate change and coastal development on these species.

Calcification in Three Common Calcified Algae from Phuket, Thailand: Potential Relevance on Seawater Carbonate Chemistry and Link to Photosynthetic Process.

Calcifying macroalgae contribute significantly to the structure and function of tropical marine ecosystems. Their calcification and photosynthetic processes are not well understood despite their critical role in marine carbon cycles and high vulnerability to environmental changes. This study aims to provide a better understanding of the macroalgal calcification process, focusing on its relevance concerning seawater carbonate chemistry and its relationship to photosynthesis in three dominant calcified macroalgae in Thailand, Padina boryana, Halimeda macroloba and Halimeda opuntia. Morphological and microstructural attributes of the three macroalgae were analyzed and subsequently linked to their calcification rates and responses to inhibition of photosynthesis. In the first experiment, seawater pH, total alkalinity and total dissolved inorganic carbon were measured after incubation of the macroalgae in the light and after equilibration of the seawater with air. Estimations of carbon uptake into photosynthesis and calcification and carbon release into air were obtained thereafter. Our results provide evidence that calcification of the three calcified macroalgae is a potential source of CO2, where calcification by H. opuntia and H. macroloba leads to a greater release of CO2 per biomass weight than P. boryana. Nevertheless, this capacity is expected to vary on a diurnal basis, as the second experiment indicates that calcification is highly coupled to photosynthetic activity. Lower pH as a result of inhibited photosynthesis under darkness imposes more negative effects on H. opuntia and H. macroloba than on P. boryana, implying that they are more sensitive to acidification. These effects were worsened when photosynthesis was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea, highlighting the significance of photosynthetic electron transport-dependent processes. Our findings suggest that estimations of the amount of carbon stored in the vegetated marine ecosystems should account for macroalgal calcification as a potential carbon source while considering diurnal variations in photosynthesis and seawater pH in a natural setting.

Experimental Assessment of Vulnerability to Warming in Tropical Shallow-Water Marine Organisms

Tropical shallow-water habitats represent the marine environments with the greatest biodiversity; however, these habitats are the most vulnerable to climate warming. Corals, seagrasses, and macroalgae play a crucial role in the structure, functions, and processes of the coastal ecosystems. Understanding their growth and physiological responses to elevated temperature and interspecific sensitivity is a necessary step to predict the fate of future coastal community. Six species representatives, including Pocillopora acuta, Porites lutea, Halophila ovalis, Thalassia hemprichii, Padina boryana, and Ulva intestinalis, collected from Phuket, Thailand, were subjected to stress manipulation for 5 days. Corals were tested at 27, 29.5, 32, and 34.5°C, while seagrasses and macroalgae were tested at 27, 32, 37, and 42°C. After the stress period, the species were allowed to recover for 5 days at 27°C for corals and 32°C for seagrasses and macroalgae. Non-destructive evaluation of photosynthetic parameters (Fv/Fm, Fv/F0, ϕPSII and rapid light curves) was carried out on days 0, 3, 5, 6, 8, and 10. Chlorophyll contents and growth rates were quantified at the end of stress, and recovery periods. An integrated biomarker response (IBR) approach was adopted to integrate the candidate responses (Fv/Fm, chlorophyll content, and growth rate) and quantify the overall temperature effects. Elevated temperatures were found to affect photosynthesis, chlorophyll content, and growth rates of all species. Lethal effects were detected at 34.5°C in corals, whereas adverse but recoverable effects were detected at 32°C. Seagrasses and macroalgae displayed a rapid decline in photosynthesis and lethal effects at 42°C. In some species, sublethal stress manifested as slower growth and lower chlorophyll content at 37°C, while photosynthesis remained unaffected. Among all, T. hemprichii displayed the highest thermotolerance. IBR provided evidence that elevated temperature affected the overall performance of all tested species, depending on temperature level. Our findings show a sensitivity that differs among important groups of tropical marine organisms inhabiting the same shallow-water environments and highlights the importance of integrating biomarkers across biological levels to assess their vulnerability to climate warming.

Screening and evaluation of different algal extracts and prospects for controlling the disease vector mosquito Culex pipiens L.

Continual application of synthetic insecticides in controlling mosquito larvae has resulted in several problems as build-up of mosquito resistance beside to negative impacts on human health and environment. Discovering new and affordable bio-insecticidal agents with high efficiency, cost effective and target specific become a crucial need. The current study assessed the larvicidal activity of eight methanolic algal extracts belong to three different algal divisions against the 3rd larval instar of Culex pipiens L. (Diptera: Culicidae). Comparative studies showed that four species of red and green algal extracts exhibited good larvicidal activity. Galaxaura elongata and Jania rubens (Rhodophyta), Codium tomentosum and Ulva intestinales (Chlorophyta) showed higher larvicidal potencies than Padina boryana, Dictyota dichotoma, and Sargassum dentifolium (Phaeophyta) and Gelidium latifolium (Rhodophyta). The maximum level of toxicity was achieved by exposure to G. elongata extract with LC50 (31.13 ppm), followed by C. tomentosum (69.85 ppm) then J. rubens (84.82 ppm) and U. intestinalis (97.54 ppm), while the lowest toxicity exhibited by G. latifolium (297.38 ppm) at 72 h post- treatment. The application of LC50 values of G. elongate, J. rubens, C. tomentosum, and U. intestinalis extracts affected the activities of antioxidant enzymes viz. superoxide dismutase, catalase and glutathione peroxidase as oxidative stress markers. An increase of antioxidant enzymes activities was recorded. Therefore, a significant elimination of free radicals, causing toxic effects. Overall, this study casts light on the insecticidal activity of some algal extracts, suggesting the possibility of application of these bio- agents as novel and cost- effective larvicides.

Padina boryana mediated green synthesis of crystalline palladium nanoparticles as potential nanodrug against multidrug resistant bacteria and cancer cells

Green synthesized nanoparticles (NPs) have emerged as a new and promising alternative to overcome the drug resistance problem. Peculiar nano-specific features of palladium NPs (Pd-NPs) offer invaluable possibilities for clinical treatment. Due to the development of multi-drug resistance (MDR) in pathogenic bacteria and the prevalence of cancers, use of algae-mediated Pd-NPs could be a prospective substitute. Therefore, Pd-NPs were synthesized by a one-step, cost-effective, and environmentally friendly green method using the extract from a brown alga, Padina boryana (PB-extract), and evaluated for their antibacterial, antibiofilm, and anticancer activities. Pd-NPs were physicochemically characterized for size, shape, morphology, surface area, charge, atomic composition, crystal structure, and capping of Pd-NPs by PB-extract biomolecules by various techniques. The data revealed crystalline Pd-NPs with an average diameter of 8.7 nm, crystal size/structure of 11.16 nm/face-centered cubic, lattice d-spacing of 0.226 nm, 28.31% as atomic percentage, surface area of 16.1 m2/g, hydrodynamic size of 48 nm, and zeta-potential of − 28.7 ± 1.6 mV. Fourier-transform infrared spectroscopy (FT-IR) analysis revealed the role of PB-extract in capping of Pd-NPs by various functional groups such as –OH, C=C, C–O, and C–N from phenols, aliphatic hydrocarbons, aromatic rings, and aliphatic amine. Out of 31, 23 compounds were found involved in biosynthesis by Gas chromatography–mass spectrometry (GC–MS) analysis. Isolated strains were identified as MDR Staphylococcus aureus, Escherichia fergusonii, Acinetobacter pittii, Pseudomonas aeruginosa, Aeromonas enteropelogenes, and Proteus mirabilis and Pd-NPs exhibited strong antibacterial/antibiofilm activities against them with minimum inhibitory concentration (MIC) in the range of 62.5–125 μg/mL. Moreover, cell viability assays showed concentration-dependent anti-proliferation of breast cancer MCF-7 cells. Pd-NPs also enhanced mRNA expression of apoptotic marker genes in the order: p53 (5.5-folds) > bax (3.5-folds) > caspase-3 (3-folds) > caspase-9 (2-folds) at 125 μg/mL. This study suggested the possible role of PB-extract capped Pd-NPs for successful clinical management of MDR pathogens and breast cancer cells.

Responses of two common coral reef macroalgae to nutrient addition, sediment addition, and mechanical damage

Shifts from coral-dominated to macroalgal-dominated states on coral reefs are typically attributed to overfishing, often in combination with natural or other anthropogenic disturbances. However, a recent study attributed increased macroalgal cover to enhanced nutrient supplies alone without associated reductions in herbivorous fishes. This highlights the need to understand macroalgal responses to terrestrial runoff and how this can contribute to their proliferation on coral reefs. We explored the responses of two common brown macroalgae, Sargassum mangarevense (Grunow) Setchell and Padina boryana Thivy to nutrient addition, sediment addition, and mechanical damage in 3 field experiments. In the first experiment, we exposed all experimental units to herbivores and found that nutrient addition ameliorated biomass loss of both S. mangarevense and P. boryana by 79% and 47%, respectively, while sediment addition had no effect on either species. Exploring the underlying causes of these findings, we determined nutrient addition caused a 5% increase in toughness of S. mangarevense and a 51% increase in calcification of P. boryana. In a final experiment, both mechanical damage and nutrient addition independently increased calcification of P. boryana, while an antagonistic interaction between these factors for S. mangarevense suggests an upper limit to thallus toughness. Overall, we demonstrate that nutrients from anthropogenic terrestrial runoff may support macroalgal proliferation on coral reefs by ameliorating short-term biomass losses in the presence of herbivores. Further, we suggest the mechanism behind this amelioration may be changes in algal physical characteristics, specifically thallus toughness and calcification, in response to anthropogenic or natural disturbances.

Particulate Matter-Induced Inflammation/Oxidative Stress in Macrophages: Fucosterol from Padina boryana as a Potent Protector, Activated via NF-κB/MAPK Pathways and Nrf2/HO-1 Involvement.

Fucosterol is a phytosterol that is abundant in marine brown algae and is a renowned secondary metabolite. However, its ability to protect macrophages against particulate matter (PM) has not been clarified with regard to inflammation; thus, this study aimed to illustrate the above. Padina boryana, a brown algae that is widespread in Indo–Pacific waters, was applied in the isolation of fucosterol. Isolation was conducted using silica open columns, while identification was assisted with gas chromatography-mass spectroscopy (GC-MS) and NMR. Elevated levels of PM led the research objectives toward the implementation of it as a stimulant. Both inflammation and oxidative stress were caused due the fact of its effect. RAW 264.7 macrophages were used as a model system to evaluate the process. It was apparent that the increased NO production levels, due to the PM, were mediated through the inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines (i.e., interleukin-6 (IL-6), interleukin-1 (IL-1β) and tumor necrosis factor-α (TNF-α), including prostaglandin E2 (PGE2)). Further, investigations provided solid evidence regarding the involvement of NF-κB and mitogen-activated protein kinases (MAPKs) in the process. Oxidative stress/inflammation which are inseparable components of the cellular homeostasis were intersected through the Nrf2/HO-1 pathway. Conclusively, fucosterol is a potent protector against PM-induced inflammation in macrophages and hence be utilized as natural product secondary metabolite in a sustainable manner.

Alginic Acid from Padina boryana Abate Particulate Matter-Induced Inflammatory Responses in Keratinocytes and Dermal Fibroblasts.

Particulate matter (PM) is a significant participant in air pollution and is hence an inducer of serious health issues. This study aimed to evaluate the dust protective effects of alginate from Padina boryana (PBA) via inflammatory-associated pathways to develop anti-fine dust skincare products. In between the external and internal environments, the skin is considered to be more than a physical barrier. It was observed that PM stimulates inflammation in the skin via activating NF-κB and MAPK pathways. The potential of PBA to inhibit the studied pathways were evident. The metal ion content of PM was considerably reduced by PBA and thus attributed to its chelation ability. Current research demonstrated the potential of P. boryana alginates to be implemented as a protective barrier against inflammation imposed with heavy metal and bacterial-derived endotoxin bound to the surface of the PM. Concisely, the results suggest that the bioactive components derived from the brown algae Padina boryana increased the cellular resistance to PM-stimulated inflammation-driven skin damage.

Functional polysaccharides of fucoidan, laminaran and alginate from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana)

Brown seaweeds are rich source of functional polysaccharides that exhibit various bioactivities. However, Malaysian seaweeds are under-utilised, leading to low revenue throughout the supply chain of the seaweed industry. The aims of this study were to extract the functional polysaccharides, namely fucoidan (F), laminaran (L) and alginate (A) from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana) and subsequently evaluate the properties of the extracted polysaccharides. P. boryana recorded the significantly (p ≤ 0.05) highest carbohydrate content (74.78 ± 1.63%) with highest fucoidan yield (Fpad = 1.59 ± 0.16%) while T. ornata contained significantly (p ≤ 0.05) highest alginate yield (Atur = 105.19 ± 3.45%). Water activities of these extracted polysaccharides varied from 0.63–0.71 with average score of browning indexes (~40). Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that the extracted polysaccharides exhibited similar spectral pattern of spectra with the respective standards. Meanwhile, laminaran extracts showed the significantly highest (p ≤ 0.05) total phenolic contents (Lsar = 43.29 ± 0.43 mgGAE/g) and superoxide anion scavenging activity (Lsig = 21.7 ± 3.6%). On the other hand, the significantly highest (p ≤ 0.05) DPPH scavenging activity was recorded in alginate with Asar at 85.3 ± 0.8%. These findings reported the properties and bioactivities of natural polysaccharides from Malaysian brown seaweeds that revealed the potential to develop high-value functional ingredients from Malaysian brown seaweeds.

Bioactivity of Ellagic Acid and Velutin: Two Phenolic Compounds Isolated from Marine Algae

MARINE macroalgae are considered as a promising source of chemical compounds with a broad array of biological activities. The bioactive compounds of five marine seaweeds (Ulva lactuca, Padina boryana, Cystoseira myrica, Liagora farinosa and Acanthophora spicifera) were extracted by chloroform, dichloromethane and ethanol. We managed to extract two polyphenolic compounds (ellagic acid and velutin) from the dichloromethane extract of P. boryana and ethanol extract of A. spicifera, respectively. The biological activities of the two isolated compounds as well as the crude extracts were screened. All tested algal extracts showed high antimicrobial activity against target bacteria and fungi except for Pseudomonas aeruginosa was resistant to U. lactuca and C. myrica extracts. Chloroform and ethanol extracts of A. spicifera, and dichloromethane extract of C. myrica showed the highest antimicrobial activity against Bacillus subtilis and Staphylococcus aureus. Dichloromethane extract of P. boryana had the highest antiprotozoal activity against Trypanosoma cruzi and Leishmania donovani (IC50 values, 3.5 and 4.8 μg/mL, respectively), and potent antioxidant activity up to 60 %. Overall, marine macroalgae with high polyphenols and flavonoids content exhibited excellent antimicrobial, antiprotozoal and antioxidant properties. Purified velutin recorded high antimicrobial activities as compared to the tested antibiotics and both ellagic acid and velutin also possessed considerable antiprotozoal activities. This study suggests that, ellagic acid and velutin comprise the key players for the antimicrobial and antiprotozoal activities of P. boryana and A. spicifera extracts, respectively. Thus, these two compounds could be used as pharmaceutically bioactive natural compounds.

Effect of sampling time on the heavy metal concentrations of brown algae: A bioindicator study on the Arabian Gulf coast

Macroalgae have often been studied as bioindicators for heavy metal pollution on sea coasts including the Arabian Gulf. On the Arabian Gulf coasts, heavy metals are continuously being released by industrial activities and therefore, pollution monitoring is needed. Biomonitoring studies using macroalgae has given highly different assessments due to the variability in algal species and sampling time points. We carried out a systematic monthly sampling of brown algae (Phaeophyta) from three locations on the western coast of the Arabian Gulf between September and February 2018. One urban area (Uqair) and two oil refining areas (Ras Tanura and Jubail) were monitored due to they have a common brown macroalgae species composition. The incidence of Cystoseira myrica, C. trinodis C. osmundacea, Hormophysa cuneiformis, Sargassum aquifolium, S. latifolium, S. filipendula and Padina boryana varied among the sites and with the time of year within the sites. The concentrations of Co, Cd and Pb varied among the sampling sites, the algal species and the sampling time points remarkably. A tentative time-trend increasing towards February was observed for some species. However, it appeared that neither optimum sampling time point, nor superior brown algae species could be recommended. The highest heavy metal accumulation was observed in Padina boryana. However, this species grew only on the two oil polluted sites. We concluded that some brown algae species can be used for biomonitoring heavy metal pollution on the western coast of the Arabian Gulf. The species incidence should be monitored systematically and the species used should be chosen locally and sampled at the same time of the year.

Antioxidant Potential of Sulfated Polysaccharides from Padina boryana; Protective Effect against Oxidative Stress in In Vitro and In Vivo Zebrafish Model.

Elevated levels of reactive oxygen species (ROS) damage the internal cell components. Padina boryana, a brown alga from the Maldives, was subjected to polysaccharide extraction. The Celluclast enzyme assisted extract (PBE) and ethanol precipitation (PBP) of P. boryana were assessed against hydrogen peroxide (H2O2) induced cell damage and zebra fish models. PBP which contains the majority of sulfated polysaccharides based on fucoidan, showed outstanding extracellular ROS scavenging potential against H2O2. PBP significantly declined the intracellular ROS levels, and exhibited protection against apoptosis. The study revealed PBPs’ ability to activate the Nrf2/Keap1 signaling pathway, consequently initiating downstream elements such that catalase (CAT) and superoxide dismutase (SOD). Further, ROS levels, lipid peroxidation values in zebrafish studies were declined with the pre-treatment of PBP. Collectively, the results obtained in the study suggest the polysaccharides from P. boryana might be a potent source of water soluble natural antioxidants that could be sustainably utilized in the industrial applications.

Padina boryana, a brown alga from the Maldives: inhibition of \u03b1-MSH-stimulated melanogenesis via the activation of ERK in B16F10 cells

BackgroundThe present study investigates the potent skin whitening ability of ethanol extract from the brown alga, Padina boryana (PBE) which was collected in the shores of Fulhadhoo Island, the Maldives, and its specific pathways of action. The effect of PBE which contains a rich amount of polyphenols was evaluated using B16F10 murine melanoma cells and provides insight to the underlying mechanisms with reference to the inhibition of melanin formation.MethodsMelanin synthesis and cellular tyrosinase inhibition were assessed in the α-MSH-stimulated melanocytes. Melanogenic pathway-related protein expressions were investigated via Western blotting. ERK 42/44 was particularly examined considering its involvement in the melanogenic pathway. Further, RT-qPCR techniques were involved in gene expression analysis.ResultsPBE dose-dependently inhibited the cellular melanin synthesis and tyrosinase levels. Western blotting revealed the potential of PBE to downregulate microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 and protein-2 (TRP-1 and TRP-2). Moreover, results explained the phosphorylation of ERK was sustained via PBE and hence declined the ultimate melanin synthesis. Gene expression analysis reinforced the results obtained.ConclusionsThe study provides substantial evidence to express the potential of PBE to inhibit B16F10 melanoma cell melanin synthesis. Concisely, results suggest the ability of PBE to be involved in medicinal and cosmeceutical applications.