Optimization and validation of reverse phase HPLC method for qualitative and quantitative assessment of polyphenols in seaweed

Nutraceutical benefits of seaweeds and their phytocompounds: a functional approach to disease prevention and management

Seaweeds (SWD), macroalgae or sea vegetables are a diverse group of over 9000 macroscopic and multicellular marine algae taxonomically classified (based on morphology and pigmentation) as green, brown and red algae. With microalgae, SWD represents one of the most researched oceanic resources turned to as treasure troves of bioactive compounds with ethnomedicinal, pharmaceutical, cosmeceutical and dietetic end-uses for millennia. This review compiles the nutraceutical uses of SWD and their bioactive compounds in nutrition and traditional management of diseases, offering future perspectives on using this group of organisms to improve human life. The review reveals that the nutraceutical application of SWD as nutrient-dense marine foods for treating diseases may be correlated with their inherent biosynthesis and possession of minerals, vitamins, dietary fibres and bioactive compounds. Compounds of algal origin have been validated and found to elicit antimicrobial, anti-inflammatory, free radical scavenging (antioxidant), antiproliferative and antidiabetic activities, among others. © 2025 Society of Chemical Industry.

Malatya apricot gum: A source of natural gum and its physicochemical, functional and antioxidant properties

Gums are commonly used in the food industry for their functional properties. However, the growing demand for sustainable and alternative sources has drawn attention to the need for identifying and characterizing non-conventional gum sources with comparable or enhanced features. This study aimed to investigate the exudate gum from apricot trees (Prunus armeniaca) in Malatya as a potential alternative. Since the composition and physicochemical properties of plant exudates can be affected by climate and growing region, our aim was to investigate the differences in the properties of the gum collected from Malatya apricot trees. The crude gum (CG) was purified (PG) and analyzed for its composition and properties. Approximate compositional analysis showed that CG consisted of 68.20 % carbohydrates, 2.23 % protein, 12.37 % moisture, and 4.37 % ash. These values, except for moisture content and fat, increased upon purification. The gum had a molecular weight of 5.55 × 105 Da, which remained unchanged upon purification. Galactose and arabinose were the main components of the sugar composition of the gum, with minor contributions from xylose and rhamnose, which showed variations in ratio after purification. Color metrics also indicated an increase in lightness (L*) and yellowness (b*) and a decrease in greenness (a*) after purification. The native pH of PG solution was found to be similar to that of CG and below 7 due to the presence of uronic acid residues in the gum structure, as confirmed by FTIR analysis. The total phenolic content was determined to be 1.14 mg GAE/g in CG and 1.17 mg GAE/g in PG, resulting in a higher antioxidant capacity for the latter. Purification also increased the content of dietary fibers from 1.61 % to 2.85 %. DSC analysis revealed that PG had higher thermal stability compared to CG. SEM images demonstrated that the gum particles were irregularly shaped, non-uniformly sized, and had rough and indented surfaces. Based on their Carr's index and Hausner ratio, both forms of apricot gum were classified as good flowable powders. These findings demonstrate the similarity of apricot gum to other tree exudates and highlight its potential as a new gum source. However, further studies are needed to determine its potential for industrial applications.

Molecular weight distribution and structure analysis of phlorotannins in Sanhai kelp (Saccharina japonica) and evaluation of their antioxidant activities

In this paper, the structures and composition of phlorotannins with different molecular weights in juvenile and mature kelp (Saccharina japonica), as well as their relationship with antioxidant activity were comprehensively analyzed. Macroporous resin and ultrafiltration were used to obtain phlorotannins with different molecular weights. The structures of low molecular weight and high molecular weight phlorotannins in Sanhai kelp were analyzed using UHPLC-Q-Orbitrap-MS/MS and NMR techniques, respectively. In addition, the antioxidant capacity of phlorotannins with different molecular weights was determined by chemical and HepG2 cell oxidative damage models methods assays. Results showed that the content and molecular weight distribution of phlorotannins in Sanhai kelp were related to its growth stage. Seventeen low molecular weight phlorotannins were identified, and the composition types of the high molecular weight phlorotannins were fucols, phlorethols, fucophlorethols, fuhalols and eckols. In addition, high molecular weight phlorotannins exhibit higher antioxidant activity than low molecular weight phlorotannins.

Polyphenolic extracts from Diospyros kaki and Vitis vinifera by-products stimulate cytoprotective effects in bacteria-cell host interactions by mediation of transcription factor Nrf2

BACKGROUND

The intestinal and skin epithelium play a strong role against bacterial stimuli which leads to inflammation and oxidative stress when overwhelmed. Polyphenols from fruit-rich diets and by-products show promise against bacterial deleterious effects; however, their antibacterial and health-promoting effects remain understudied.

PURPOSE

This study aimed to assess the impact of polyphenolic extracts of grape (GrPE), persimmon (PePE) and pomegranate (PoPE) by-products on bacterial pathogen-host interactions, focusing beyond growth inhibition to explore their effects on bacterial adhesion, invasion, and modulation of host responses.

METHODS

The microdilution method, as well as the tetrazolium based MTT cell proliferation and cytotoxicity assay with crystal violet staining were used to identify extracts sub-inhibitory concentrations that interfere with bacterial adhesion, invasion or lipopolysaccharides (LPS) effect on cell hosts without compromising host viability. The cytoprotective effects of extracts were assessed in a knock-down model of nuclear factor erythroid 2-related factor 2 (Nrf2).

RESULTS

All extracts demonstrated significant reductions in pathogen adhesion to Caco-2 and HaCaT cells while preserving cellular integrity. Notably, PePE exhibited specific efficacy against Salmonella enterica adhesion, attributed mostly to its gallic acid content, whereas PoPE reduced S. enterica invasion in Caco-2 cells. The extracts supported the prevalence of non-pathogenic and commensal strains of intestinal and skin surfaces, selectively reducing pathogenic adhesion. The extracts mitigated the oxidative stress, enhanced the barrier function, and modulated the pro-inflammatory cytokines in LPS-challenged cells. GrPE, rich in anthocyanins, and PePE were found to mediate their protective effects through Nrf2 activation, while PoPE exerted multifaceted actions independent of Nrf2.

CONCLUSION

Our results highlight the therapeutic potential of GrPE, PePE, and PoPE in shaping bacterial-host interactions, endorsing their utility as novel nutraceuticals for both oral and topical applications to prevent potential bacterial infections through innovative mechanisms.

Optimizing extraction methods by a comprehensive experimental approach and characterizing polyphenol compositions of Ecklonia radiata

Brown seaweed Ecklonia radiata harbors valuable polyphenols, notably phlorotannins, prized for their health benefits. This study optimized phlorotannin extraction via conventional solvent extraction and ultrasound-assisted extraction methods, utilizing variable concentrations of ethanol. Employing fractional factorial designs, key variables were identified. Steepest ascent/descent method and central composite rotatable designs refined optimal conditions, enhancing phlorotannin and polyphenol yields, and antioxidant capacities. Under optimized conditions, phlorotannin contents reached 2.366 ± 0.01 and 2.596 ± 0.04 PGE mg/g, total polyphenol contents peaked at 10.223 ± 0.03 and 10.836 ± 0.02 GAE mg/g. Robust antioxidant activity was observed: DPPH and OH radical scavenging capacities measured 27.891 ± 0.06 and 17.441 ± 0.08 TE mg/g, and 37.498 ± 1.12 and 49.391 ± 0.82 TE mg/g, respectively. Reducing power capacities surged to 9.016 ± 0.02 and 28.110 ± 0.10 TE mg/g. Liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography (HPLC) analyses revealed enriched antioxidant compounds. Variations in polyphenol profiles were noted, potentially influencing antioxidant capacity nuances. This study illuminated the potential of E. radiata potential as a polyphenol source and offers optimized extraction methods poised to benefit various industries.

Free and bound phenolic profiles and antioxidant ability of eleven marine macroalgae from the South China Sea

Marine macroalgae are of broad interest because of their abundant bioactive phenolic compounds. However, only a few previous studies have focused on bound phenolic compounds. In this study, there were significant differences in total phenolic content, total phlorotannin content, total flavonoid content, and antioxidant ability in free and bound forms, as well as in their bound-to-free ratios, among 11 marine macroalgal species from the South China Sea. Padina gymnospora had the highest total phenolic content of free fractions, and total phlorotannin content, total flavonoid content, and antioxidant activity of free fractions. Sargassum thunbergii had the highest total phlorotannin content of bound fractions, whereas Sargassum oligocystum had the highest total flavonoid content and total phenolic content of bound fractions. Moreover, 15 phenolic acids, 35 flavonoids, 2 stilbenes, 3 bromophenols, and 3 phlorotannins were characterized and quantified using ultra-high-performance liquid chromatography with Xevo triple quadrupole mass spectrometry, and 42 phenolic compounds were reported in the bound fractions of seaweeds for the first time. Among the species, the number and amount of free and bound phenolic compounds varied greatly and the main components were different. Padina gymnospora had the largest total phenolic number, while Turbinaria ornata showed the highest total phenolic amount. Coutaric acid and diosmetin were dominant in Sargassum polycystum, and hinokiflavone was dominant in Caulerpa lentillifera, and cyanidin was dominant in the other seaweeds. Hierarchical cluster analysis was used to divide the seaweed species into seven groups. This study revealed that Padina gymnospora, Sargassum thunbergii, Turbinaria ornata, and Sargassum oligocystum are promising functional food resources.

Development of a high-performance liquid chromatography method for simultaneous quantification of sixteen polyphenols and application to tomato

The main purpose of the current work was to develop a new method to evaluate and quantify sixteen polyphenol compounds from tomato fruit using high-performance liquid chromatography (HPLC). The separation of 16 polyphenols from tomato fruit was achieved in < 60 min by using a Waters Symmetry C18 column (250 × 4.6 mm i. d, 5 µm particle sizes) with a gradient system of ultrapure water (1 % acetic acid) and 100 % methanol, a temperature of 30 °C, an injection volume of 10 μL and a flow rate of 1.1 mL/min, respectively. The analytical characteristics of evaluation method provide sufficient sensitivity for all tomato polyphenols compounds within normal range 0.1-20 μg·mL-1 (R2≥0.999) with 0.069-0.365 μg·mL-1 LOD, and 0.171-1.106 μg·mL-1 LOQ, with good system suitability (<2 % RSD of retention time, peak area, and tailing factor, 6,000-1,336,000 N, and >1.5 peak resolution), <10 % RSD of precision, stability, repeatability, and robustness, and 99.2 - 105.0 % of recovery. The applicability of this method was demonstrated by the determination of polyphenols in nine cultivars of tomatoes. The results showed that '184' possessed the highest content of total polyphenols (1249.53 μg·g-1 DW) followed by 'Disease resistance 184' (1064.93 μg·g-1 DW). The main polyphenol components were rutin, quercetin, gallic acid, chlorogenic acid, 2,5-dihydroxy benzoic acid, caffeic acid and benzoic acid in tomato fruits. In conclusion, this novel HPLC method is useful and acceptable to analyze polyphenols in tomato fruit.

Marine Polyphenols in Cardiovascular Health: Unraveling Structure-Activity Relationships, Mechanisms, and Therapeutic Implications

Cardiovascular diseases (CVDs) are responsible for significant mortality rates globally that have been raised due to the limitation of the available treatments and prevalence of CVDs. The innovative research and identification of potential preventives for CVDs are essential to alleviate global deaths and complications. The marine environment is a rich source of bioactive substances and provides a unique chemical arsenal against numerous ailments due to its unrivaled biodiversity. Marine polyphenolic compounds (MPCs) are unique because of their structural variety and biologically significant activity. Further, MPCs are well-reported for their valuable biological activities, such as anti-inflammatory, cardioprotective, and antioxidant, demonstrating encouraging results in preventing and treating CVDs. Therefore, investigation of the structure-activity relationship (SAR) between MPCs and CVDs provides insights that reveal how the structural components of these compounds affect their effectiveness. Further, comprehending this correlation is essential for advancing medications and nutraceuticals sourced from marine sources, which could transform the strategy for treating and preventing cardiovascular diseases. Therefore, this study provides a comprehensive analysis of existing research by emphasizing the role of MPCs in CVD treatments and evaluating the SAR between MPCs and CVDs with challenges and future directions.

Exploring the Potential of Invasive Species Sargassum muticum: Microwave-Assisted Extraction Optimization and Bioactivity Profiling

Sargassum muticum (SM) poses a serious environmental issue since it is a fast-expanding invasive species occupying key areas of the European shoreline, disrupting the autochthonous algae species, and disturbing the ecosystem. This problem has concerned the general population and the scientific community. Nevertheless, as macroalgae are recognized as a source of bioactive molecules, the abundance of SM presents an opportunity as a raw material. In this work, response surface methodology (RSM) was applied as a tool for the optimization of the extraction of bioactive compounds from SM by microwave-assisted extraction (MAE). Five different parameters were used as target functions: yield, total phenolic content (TPC); and the antioxidant measurements of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and β-carotene bleaching (BC). After the optimal extraction conditions were determined (time = 14.00 min; pressure = 11.03 bar; ethanol = 33.31%), the chemical composition and bioactivity of the optimum extract was evaluated to appraise its antioxidant capability to scavenge reactive species and as a potential antibacterial, antidiabetic, antiproliferation, and neuroprotective agent. The results lead to the conclusion that MAE crude extract has bioactive properties, being especially active as an antiproliferation agent and as a nitric oxide and superoxide radical scavenger.

Chemical fingerprinting and multicomponent quantitative analysis for quality control of Cinnamomum tamala collected from Western Himalaya by HPLC-DAD

Cinnamomum tamala, commonly known as "Indian bay leaf" or "Tejpat", is an economically important plant widely used in medicine, food and cosmetic industries. Growing demand for its leaf and bark in the herbal trade and non-availability of quality materials lead to large-scale species admixture and adulteration in the global market. The present study aims at developing a validated HPLC-DAD (High-performance liquid chromatography coupled with diode array detection) method and multiple markers-based chemical fingerprints for quality evaluation of C. tamala leaf extracts. Five bioactive compounds, viz., coumarin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and cinnamyl acetate, were identified and quantified in 28 samples collected from the western Himalayan region of India. The chromatographic separation was achieved on Shimadzu Shimpak C18 column (dimension 250 × 4.6 mm, pore size 5 μm) with a gradient elution of mobile phase using acetonitrile and 0.1 percent phosphate buffer and the chromatograms were obtained at a wavelength of 265 nm. The method validation was done by analyzing the linearity, LOD, LOQ, precision, stability, repeatability and recovery rates of standard compounds for quantitative analysis. The values of coefficient of correlation (R2) were found to be close to 1 for linearity and similarity analysis; and standard deviation was less than 3 percent in case of precision, stability, repeatability and recovery rates. The content of target compounds such as coumarin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and cinnamyl acetate varied in the range of 0-1.09, 0-0.05, 0.07-0.51, 0.39-1.27 and 0-0.27 percent, respectively. In the chemical fingerprint of C. tamala leaves, a total of 13 peaks were assigned as common peaks. The results of the study indicated that the HPLC method now developed combining chemical fingerprint with quantification of analytes could serve as a useful tool for quality evaluation of herbal raw materials of C. tamala and a valuable reference for further study.

Seaweed-derived phenolic compounds as diverse bioactive molecules: A review on identification, application, extraction and purification strategies

Seaweed, a diverse group of marine macroalgae, has emerged as a rich source of bioactive compounds with numerous health-promoting properties. Among these, phenolic compounds have garnered significant attention for their diverse therapeutic applications. This review examines the methodologies employed in the extraction and purification of phenolic compounds from seaweed, emphasizing their importance in unlocking the full potential of these oceanic treasures. The article provides a comprehensive overview of the structural diversity and biological activities of seaweed-derived phenolics, elucidating their antioxidant, anti-inflammatory, and anticancer properties. Furthermore, it explores the impact of extraction techniques, including conventional methods and modern green technologies, on the yield and quality of phenolic extracts. The purification strategies for isolating specific phenolic compounds are also discussed, shedding light on the challenges and advancements in this field. Additionally, the review highlights the potential applications of seaweed-derived phenolics in various industries, such as pharmaceuticals, cosmetics, and functional foods, underscoring the economic value of these compounds. Finally, future perspectives and research directions are proposed to encourage continued exploration of seaweed phenolics, fostering a deeper understanding of their therapeutic potential and promoting sustainable practices in the extraction and purification processes. This comprehensive review serves as a valuable resource for researchers, industry professionals, and policymakers interested in harnessing the untapped potential of phenolic compounds from seaweed for the betterment of human health and environmental sustainability.

Optimization of Ultrasonic Extraction Parameters for the Recovery of Phenolic Compounds in Brown Seaweed: Comparison with Conventional Techniques

Seaweed, in particular, brown seaweed, has gained research interest in the past few years due to its distinctive phenolic profile that has a multitude of bioactive properties. In order to obtain the maximum extraction efficiency of brown seaweed phenolic compounds, Response Surface Methodology was utilized to optimize the ultrasound-assisted extraction (UAE) conditions such as the amplitude, time, solvent:solid ratio, and NaOH concentration. Under optimal conditions, UAE had a higher extraction efficiency of free and bound phenolic compounds compared to conventional extraction (stirred 16 h at 4 °C). This led to higher antioxidant activity in the seaweed extract obtained under UAE conditions. The profiling of phenolic compounds using LC-ESI-QTOF-MS/MS identified a total of 25 phenolics with more phenolics extracted from the free phenolic extraction compared to the bound phenolic extracts. Among them, peonidin 3-O-diglucodise-5-O-glucoside and hesperidin 5,7-O-diglucuronide are unique compounds that were identified in P. comosa, E. radiata and D. potatorum, which are not reported in plants. Overall, our findings provided optimal phenolic extraction from brown seaweed for research into employing brown seaweed as a functional food.

A simple and robust LC-ESI single quadrupole MS-based method to analyze polyphenols in plant extracts using deep eutectic solvents

Currently, the interest in polyphenols is increasing due to their significant properties in health. Polyphenols exist in a range of natural products, however their extraction as well as their characterization are important issues as they are mainly present in complex matrices. Therefore, sensitive and selective analytical methods based on liquid chromatography coupled to tandem mass spectrometry are essential. Nevertheless, access to such high-resolution techniques is quite rare. Thus, in this work we present a simple, selective and robust method based on a single-quadrupole (Q) MS technique) for the analysis of a wide range of polyphenols such as flavonoids, phenolic acids and anthocyanins. Specifically, we present:•A simple liquid chromatography electro-spray ionization (LC-ESI) single-quadrupole mass selective (MS) method for the analysis of 18 different polyphenols.•Application of the method to three plant-based extracts that are derived after green extraction methods.

Chromatographic Methods Developed for the Quantification of Quercetin Extracted from Natural Sources: Systematic Review of Published Studies from 2018 to 2022

Quercetin (QUE) is the most widely used flavonoid for therapeutic purposes. To improve the available knowledge about the properties of some natural products, determining the amount of QUE is crucial. The main objective of this systematic review is to identify the analytical methods validated for detecting and quantifying QUE in different matrices and characterize their sensitivity. A search was conducted until 30 June 2023 in the PubMed database for experimental studies that addressed the validation of chromatographic analytical methods to detect and quantify QUE from consumable natural products. Only studies published between 2018 and 2022, written in English, were included. The risk of bias was assessed by emphasizing methods of comparison according to previously published studies. Descriptive statistics were used to depict the obtained results. The studies were analyzed based on the type of QUE source, chromatographic method, and validation parameters. A total of 17 studies were included in this review. Plants were the most commonly analyzed source of QUE. Among the detection methods, spectrophotometry proved to be the most widely used, surpassing mass spectrometry (MS). After analyzing the bias, all the included studies mentioned/presented, totally or partially, at least four of the eight parameters.

Rehashing Our Insight of Seaweeds as a Potential Source of Foods, Nutraceuticals, and Pharmaceuticals

In a few Southeast Asian nations, seaweeds have been a staple of the cuisine since prehistoric times. Seaweeds are currently becoming more and more popular around the world due to their superior nutritional value and medicinal properties. This is because of rising seaweed production on a global scale and substantial research on their composition and bioactivities over the past 20 years. By reviewing several articles in the literature, this review aimed to provide comprehensive information about the primary and secondary metabolites and various classes of bioactive compounds, such as polysaccharides, polyphenols, proteins, and essential fatty acids, along with their bioactivities, in a single article. This review also highlights the potential of seaweeds in the development of nutraceuticals, with a particular focus on their ability to enhance human health and overall well-being. In addition, we discuss the challenges and potential opportunities associated with the advancement of pharmaceuticals and nutraceuticals derived from seaweeds, as well as their incorporation into different industrial sectors. Furthermore, we find that many bioactive constituents found in seaweeds have demonstrated potential in terms of different therapeutic attributes, including antioxidative, anti-inflammatory, anticancer, and other properties. In conclusion, seaweed-based bioactive compounds have a huge potential to play an important role in the food, nutraceutical, and pharmaceutical sectors. However, future research should pay more attention to developing efficient techniques for the extraction and purification of compounds as well as their toxicity analysis, clinical efficacy, mode of action, and interactions with regular diets.

Simple and selective extraction of quercetin with microextraction in packed syringe method using modified glass powder by a molecularly imprinted polymer followed by spectrophotometric determination

A new sample preparation method based on microextraction in packed syringe was developed for preconcentration of quercetin prior to its spectrophotometric determination. Molecularly imprinted polymers as packing material was used for higher extraction efficiency. First, glass powder as support material because of low cost and available substrate was modified, and then molecularly imprinted polymers were synthesized by the sol-gel method using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as cross-linker agent. The combination of a molecularly imprinted polymers and microextraction in packed syringe increased the selectivity and sensitivity. The surface morphology and functionality of the prepared molecularly imprinted polymers was characterized using Fourier-transform infrared spectroscopy, Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis. Different influencing parameters on extraction efficiency such as effect of the number of sample sorption/desorption cycles, type and volume of desorption solvent, pH of the sample solution, and molecularly imprinted polymers amounts were optimized. Under the optimum condition, the proposed method displayed a linear range from 0.01 to 5 µg mL-1 and limit of detection 3.68 ng mL-1 . Relative standard deviation for three replicate determination of 1 µg mL-1 quercetin was 2.1 %. The proposed method was applied successfully for the selective extraction of quercetin from tea and coffee samples.

Evaluation of the antioxidant potential of brown seaweeds extracted by different solvents and characterization of their phenolic compounds by LC-ESI-QTOF-MS/MS

Seaweeds, serving as valuable natural sources of phenolic compounds (PCs), offer various health benefits like antioxidant, anti-inflammatory properties, and potential anticancer effects. The efficient extraction of PCs from seaweed is essential to harness their further applications. This study compares the effectiveness of different solvents (ethanol, methanol, water, acetone, and ethyl acetate) for extracting PCs from four seaweed species: Ascophyllum sp., Fucus sp., Ecklonia sp., and Sargassum sp. Among them, the ethanol extract of Sargassum sp. had the highest content of total phenolics (25.33 ± 1.45 mg GAE/g) and demonstrated potent scavenging activity against the 2,2-diphenyl-1-picrylhydrazyl radical (33.65 ± 0.03 mg TE/g) and phosphomolybdate reduction (52.98 ± 0.47 mg TE/g). Ecklonia sp. had the highest content of total flavonoids (0.40 ± 0.02 mg QE/g) in its methanol extract, whereas its ethyl acetate extract contained the highest content of total condensed tannins (8.09 ± 0.12 mg CE/g). Fucus sp. demonstrated relatively strong antioxidant activity, with methanolic extracts exhibiting a scavenging ability against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (54.41 ± 0.24 mg TE/g) and water extracts showing ferric-reducing antioxidant power of 36.24 ± 0.06 mg TE/g. Likewise, liquid chromatography-mass spectrometry identified 61 individual PCs, including 17 phenolic acids, 32 flavonoids, and 12 other polyphenols. Ecklonia sp., particularly in the ethanol extract, exhibited the most diverse composition. These findings underscore the importance of selecting appropriate solvents based on the specific seaweed species and desired compounds, further providing valuable guidance in the pharmaceutical, nutraceutical, and cosmetic industries. PRACTICAL APPLICATION: The PCs, which are secondary metabolites present in terrestrial plants and marine organisms, have garnered considerable attention due to their potential health advantages and diverse biological effects. Using various organic/inorganic solvents during the extraction process makes it possible to selectively isolate different types of PCs from seaweed species. The distinct polarity and solubility properties of each solvent enable the extraction of specific compounds, facilitating a comprehensive assessment of the phenolic composition found in the seaweed samples and guiding industrial production.

Nutritional and Health Benefits of the Brown Seaweed Himanthalia elongata

Himanthalia elongata is a brown seaweed containing several nutritional compounds and bioactive substances including antioxidants, dietary fibre, vitamins, fatty acids, amino acids, and macro- and trace- elements. A variety of bioactive compounds including phlorotannins, flavonoids, dietary fucoxanthin, hydroxybenzoic acid, hydroxycinnamic acid, polyphenols and carotenoids are also present in this seaweed. Multiple comparative studies were carried out between different seaweed species, wherein H. elongata was determined to exhibit high antioxidant capacity, total phenolic content, fucose content and potassium concentrations compared to other species. H. elongata extracts have also shown promising anti-hyperglycaemic and neuroprotective activities. H. elongata is being studied for its potential industrial food applications. In new meat product formulations, it lowered sodium content, improved phytochemical and fiber content in beef patties, improved properties of meat gel/emulsion systems, firmer and tougher with improved water and fat binding properties. This narrative review provides a comprehensive overview of the nutritional composition, bioactive properties, and food applications of H. elongata.

The Impact of Culinary Processing, including Sous-Vide, on Polyphenols, Vitamin C Content and Antioxidant Status in Selected Vegetables-Methods and Results: A Critical Review

This study presents various research methods and results analysis of the total antioxidant status (TAS), polyphenols content (PC) and vitamin C content in selected plant materials (vegetables) subjected to various technological processes, including sous-vide. The analysis included 22 vegetables (cauliflower white rose, romanesco type cauliflower, broccoli, grelo, col cabdell cv. pastoret, col lllombarda cv. pastoret, brussels sprouts, kale cv. crispa-leaves, kale cv. crispa-stem, toscana black cabbage, artichokes, green beans, asparagus, pumpkin, green peas, carrot, root parsley, brown teff, white teff, white cardoon stalks, red cardoon stalks and spinach) from 18 research papers published in 2017 to 2022. The results after processing by various methods such as conventional, steaming and sous-vide cooking were compared to the raw vegetable results. The antioxidant status was mainly determined by the radical DPPH, ABTS and FRAP methods, the polyphenol content by the Folin-Ciocalteu reagent and the vitamin C content using dichlorophenolindophenol and liquid chromatography methods. The study results were very diverse, but in most studies, the cooking techniques contributed to reducing TAS, PC and vitamin C content, with the sous-vide process being most beneficial. However, future studies should focus on vegetables for which discrepancies in the results were noted depending on the author, as well as lack of clarity regarding the analytical methods used, e.g., cauliflower white rose or broccoli.

Comparative Study on the Effect of Phenolics and Their Antioxidant Potential of Freeze-Dried Australian Beach-Cast Seaweed Species upon Different Extraction Methodologies

Brown seaweed is rich in phenolic compounds and has established health benefits. However, the phenolics present in Australian beach-cast seaweed are still unclear. This study investigated the effect of ultrasonication and conventional methodologies using four different solvents on free and bound phenolics of freeze-dried brown seaweed species obtained from the southeast Australian shoreline. The phenolic content and their antioxidant potential were determined using in vitro assays followed by identification and characterization by LC-ESI-QTOF-MS/MS and quantified by HPLC-PDA. The Cystophora sp. displayed high total phenolic content (TPC) and phlorotannin content (FDA) when extracted using 70% ethanol (ultrasonication method). Cystophora sp., also exhibited strong antioxidant potential in various assays, such as DPPH, ABTS, and FRAP in 70% acetone through ultrasonication. TAC is highly correlated to FRAP, ABTS, and RPA (p < 0.05) in both extraction methodologies. LC-ESI-QTOF-MS/MS analysis identified 94 and 104 compounds in ultrasound and conventional methodologies, respectively. HPLC-PDA quantification showed phenolic acids to be higher for samples extracted using the ultrasonication methodology. Our findings could facilitate the development of nutraceuticals, pharmaceuticals, and functional foods from beach-cast seaweed.

A macroporous resin purification process to obtain food-grade phlorotannin-rich extracts with α-glucosidase inhibitory activity from Chilean brown seaweeds: An UHPLC-MSn profiling

An efficient macroporous resin purification process was designed to obtain food-grade phlorotannin-rich extracts from the seaweeds Durvillaea incurvata and Lessonia spicata. Phlorotannins were profiled to relate structures with the α-glucosidase inhibitory activity of the extracts. Liquid chromatography-mass spectrometry was applied for tentative identification. The best phlorotannin purification performance was achieved with HP-20 resin and elution with 80% v/v ethanol. This is the first study that demonstrates the effectivity of HP-20 resin for removing potentially toxic elements (As, Cd) from seaweed extracts. Fucols/phlorethols/fucophlorethols isomers up to 4 phloroglucinol units (PGU) were the most representative phlorotannins. High molecular weight species (11-21 PGU), although in low abundances, were detected in D. incurvata for the first time. Eckols, carmalols, fuhalols, phenolic acids, and flavonoids were also detected. Some extracts' potent α-glucosidase inhibitory activities were related to their high phlorotannin abundances, the presence of phlorotannins of a high degree of polymerization, and the phlorotannins class.

Barbero G, Palma M, Carrera C. Optimization of a Microwave Assisted Extraction Method for Maximum Flavonols and Antioxidant Activity of Onion Extracts

Nowadays, consumers demand bioactive foods that have the potential to limit the risk of suffering from several medical conditions. Onions present these desirable capabilities owing to its high content in antioxidant bioactive compounds. This work has used a Box-Behnken design with a response surface methodology to determine the best conditions in which to extract the polyphenols that are found in onions. Two extraction methods-one for the extraction of total flavonols and another one intended to obtain extracts with the highest possible antioxidant activity-have been developed and optimized. The following factors have been studied: temperature, %methanol in water, solvent pH, and sample-solvent volumetric ratio. The optimal conditions for the extraction of flavonols were 93.8% methanol in water, pH 2, 50 °C extraction temperature and 0.2:17.9 g:mL sample-solvent ratio. The best antioxidant activity levels were registered when using 74.2% methanol in water, pH 2, 99.9 °C extraction temperature and 0.2:18.2 g:mL sample-solvent ratio. Both optimized methods used short extraction times, and presented good precision levels and successful results when used with an assortment of onion varieties. According to total flavonols and antioxidant activity data, with 7.557 ± 0.3261 and 12.08 ± 0.0379 mg g^-1, respectively, the developed methods achieved comparable or even superior results to those obtained by other authors.

Overview of Phlorotannins' Constituents in Fucales

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.

Seaweed-Derived Phenolic Compounds in Growth Promotion and Stress Alleviation in Plants

Abiotic and biotic stress factors negatively influence the growth, yield, and nutritional value of economically important food and feed crops. These climate-change-induced stress factors, together with the ever-growing human population, compromise sustainable food security for all consumers across the world. Agrochemicals are widely used to increase crop yield by improving plant growth and enhancing their tolerance to stress factors; however, there has been a shift towards natural compounds in recent years due to the detrimental effect associated with these agrochemicals on crops and the ecosystem. In view of these, the use of phenolic biostimulants as opposed to artificial fertilizers has gained significant momentum in crop production. Seaweeds are marine organisms and excellent sources of natural phenolic compounds that are useful for downstream agricultural applications such as promoting plant growth and improving resilience against various stress conditions. In this review, we highlight the different phenolic compounds present in seaweed, compare their extraction methods, and describe their downstream applications in agriculture.

Customized cationic nanoemulsions loading triamcinolone acetonide for corneal neovascularization secondary to inflammatory processes

Customized cationic oil-in-water nanoemulsions (NEs) have been produced to improve the bioavailability of poorly water-soluble drugs, such as triamcinolone acetonide (TA). TA is a synthetic glucocorticoid with anti-inflammatory and antiangiogenic therapeutic properties and it is widely used as an effective treatment in ocular disorders. In this work, TA-NEs were characterized using two different custom-made cationic surfactants, showing a high positive surface charge favouring corneal penetration and a particle size below 300 nm. Both TA-NE formulations demonstrated to be stable at 4 °C during the first months of storage. Furthermore, TA-NEs were able to produce antiangiogenic effects in chicken membranes. The TA-NEs safety profile was evaluated using in vitro and in vivo ocular tolerance tests. Out of the two formulations, the one showing no irritant effects was screened in vivo demonstrating capacity to ameliorate ocular inflammation in New Zealand rabbits significantly, specially to reduce the risk of ocular inflammation processes, with antiangiogenic activity, and can therefore be exploited as a suitable formulation to avoid inflammatory reactions upon ocular surgical procedures, such as cataracts.

Polyphenols of Edible Macroalgae: Estimation of In Vitro Bio-Accessibility and Cytotoxicity, Quantification by LC-MS/MS and Potential Utilization as an Antimicrobial and Functional Food Ingredient

Macroalgae are a rich source of polyphenols, and their ingestion promotes various health benefits. However, information on factors contributing to health benefits such as antioxidants, antimicrobial properties, bioaccessibility, and cytotoxicity is less explored and often unavailable. Therefore, this study aims to investigate the above-mentioned parameters for the brown and green macroalgae Sargassum wightii and Ulva rigida, respectively, collected from the southeast coast of India. S. wightii exhibited higher antioxidant activity and moderate antimicrobial activity against major food pathogens in an agar well diffusion assay and in the broth microdilution method (MIC50 being <0.5 mg/mL for all microorganisms tested). Both macroalgae extracts exhibited significantly high bioaccessibility of polyphenols. To evaluate the safety of the extracts, in vitro cytotoxicity by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was carried out on the primary cells: mouse splenic lymphocytes. An almost complete decline in the cell viability was seen at considerably high concentration (50 mg/mL), expressing the reasonably high safety of the extracts. The extracts of both macroalgae were quantified for polyphenols, wherein fucoxanthin (9.27 ± 2.28 mg/kg DW) and phloroglucinol (17.96 ± 2.80 mg/kg DW) were found to be greater in the S. wightii apart from other phenolics, like gallic acid, quercetin, vanillin, and ferulic acid. The results signify the tremendous scope for the value addition of S. wightii through extraction and purification of polyphenols for its potential exploitation in functional foods and nutraceuticals or as an antimicrobial ingredient in active or smart packaging.

Seaweed Exhibits Therapeutic Properties against Chronic Diseases: An Overview

Seaweeds or marine macroalgae are known for producing potentially bioactive substances that exhibit a wide range of nutritional, therapeutic, and nutraceutical properties. These compounds can be applied to treat chronic diseases, such as cancer, cardiovascular disease, osteoporosis, neurodegenerative diseases, and diabetes mellitus. Several studies have shown that consumption of seaweeds in Asian countries, such as Japan and Korea, has been correlated with a lower incidence of chronic diseases. In this study, we conducted a review of published papers on seaweed consumption and chronic diseases. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method for this study. We identified and screened research articles published between 2000 and 2021. We used PubMed and ScienceDirect databases and identified 107 articles. This systematic review discusses the potential use of bioactive compounds of seaweed to treat chronic diseases and identifies gaps where further research in this field is needed. In this review, the therapeutic and nutraceutical properties of seaweed for the treatment of chronic diseases such as neurodegenerative diseases, obesity, diabetes, cancer, liver disease, cardiovascular disease, osteoporosis, and arthritis were discussed. We concluded that further study on the identification of bioactive compounds of seaweed, and further study at a clinical level, are needed.

Effects of different extraction methods on contents, profiles, and antioxidant abilities of free and bound phenolics of Sargassum polycystum from the South China Sea

Total phenolic content (TPC), phenolic profiles, and antioxidant activity of free and bound extracts of Sargassum polycystum, obtained by different extraction solvents and hydrolysis methods, were investigated. Aqueous acetone afforded the highest free TPC and antioxidant ability, followed by aqueous ethanol and aqueous methanol. Twelve free phenolic compounds were identified by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS), including two hydroxycinnamic acids, seven flavonoids, one stilbene, and two phlorotannins. Three to nine different free phenolic compounds were extracted by these solvents with different compositions, including nine by 70% acetone and eight by 70% methanol, 70% ethanol, and 50% ethanol. The highest total content of free phenolic compounds determined by high-performance liquid chromatography-diode array detection was obtained from 70% ethanol. Alkaline hydrolysis afforded higher bound TPC (274.27 mg GAE/100 g DW) and antioxidant ability than acid hydrolysis. Five bound phenolic compounds were characterized by UHPLC-MS and five were released from alkaline hydrolysis, whereas two were released from acid hydrolysis. Total content of bound phenolic compounds released by alkaline hydrolysis was 14.68-fold higher than that by acid hydrolysis. The free and bound TPC, phenolic profiles, and antioxidant activities depended on the extraction solvent used. These results indicate that S. polycystum is a potentially useful antioxidant source and contribute to the development of seaweed-based functional foods. PRACTICAL APPLICATION: Phenolics are usually divided into free and bound forms based on their extractability and interaction with cell wall components. The nutritional effects of bound phenolics in algae have long been neglected. These topics contribute to the development of seaweed-based functional foods.

Marine algal flavonoids and phlorotannins; an intriguing frontier of biofunctional secondary metabolites

Algae are the oldest representatives of the plant world with reserves exceeding hundreds of millions of tons in the world's oceans. Currently, a growing interest is placed toward the use of algae as feedstocks for obtaining numerous natural products. Algae are a rich source of polyphenols that possess intriguing structural diversity. Among the algal polyphenols, phlorotannins, which are unique to brown seaweeds, and have immense value as potent modulators of biochemical processes linked to chronic diseases. In algae, flavonoids remain under-explored compared to other categories of polyphenols. Both phlorotannins and flavonoids are inclusive of compounds indicating a wide structural diversity. The present paper reviews the literature on the ecological significance, biosynthesis, structural diversity, and bioactivity of seaweed phlorotannins and flavonoids. The potential implementation of these chemical entities in functional foods, cosmeceuticals, medicaments, and as templates in drug design are described in detail, and perspectives are provided to tackle what are perceived to be the most momentous challenges related to the utilization of phlorotannins and flavonoids. Moving beyond: industrial biotechnology applications, metabolic engineering, total synthesis, biomimetic synthesis, and chemical derivatization of phlorotannins and flavonoids could broaden the research perspectives contributing to the health and economic up-gradation.

Metabolomic Approach for Characterization of Polyphenolic Compounds in Laminaria japonica, Undaria pinnatifida, Sargassum fusiforme and Ascophyllum nodosum

Profiling of polyphenolics in four types of brown macroalgae, namely Laminaria japonica (L. japonica), Undaria pinnatifida (U. pinnatifida), Sargassum fusiforme (S. fusiforme), and Ascophyllum nodosum (A. nodosum), and their effect on oxidation resistance were investigated for the first time. Polyphenolic extracts from marine brown macroalgae were shown to effectively remove oxidants from cells and cellular systems. A. nodosum showed the highest antioxidant activity among evaluated brown macroalgae, showing a better scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and alleviating oxidative damage caused by hydrogen peroxide to human keratinocytes (HaCaT) cells. Through Q-Exactive HF-X mass spectrometry analysis, 12 polyphenolic compounds were preliminarily identified, including phlorotannins, phenolic acids, and flavonoids. Significant differences in content and variety of polyphenolics were found in evaluated brown macroalgae, which could be related to differences in antioxidant activity in vivo and in vitro. Moreover, the antioxidant activity might be related to the total phenolic content and the types of polyphenolics, especially phlorotannins. The findings presented in this study indicate that A. nodosum could be used as an important substitute for functional ingredients in foods and pharmaceutical preparations, as well as a raw material for phlorotannins research.

Identification of Phlorotannins in the Brown Algae, Saccharina latissima and Ascophyllum nodosum by Ultra-High-Performance Liquid Chromatography Coupled to High-Resolution Tandem Mass Spectrometry

Phlorotannins are bioactive polyphenols in brown macroalgae that make these algae interesting as healthy food. Specific phlorotannins are, however, seldom identified, and extracts from different species are often only analysed for total phenolic content (TPC). In this study, our focus was to identify phlorotannin molecules from Saccharina latissima and Ascophyllum nodosum (a species rich in these compounds) using ultra-high-performance liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS2). Water and ethanol (30 and 80% v/v) were used at solid:liquid ratios, extraction times and temperatures, proposed to result in high TPC in extracts from other species. The S. latissima extracts, however, did not allow phlorotannin detection by either UHPLC-UV/Vis or UHPLC-HRMS2, despite a TPC response by the Folin-Ciocalteu assay, pinpointing a problem with interference by non-phenolic compounds. Purification by solid phase extraction (SPE) led to purer, more concentrated fractions and identification of four phlorotannin species in A. nodosum and one in S. latissima by UHPLC-HRMS2, using extracts in ethanol 80% v/v at a solid:liquid ratio of 1:10 for 20 h at 25 °C with an added 10 h at 65 °C incubation of remaining solids. The phlorotannin with the formula C12H10O7 (corresponding to bifuhalol) is the first identified in S. latissima.

Comparative analysis of the morphological property and chemical composition of soluble and insoluble dietary fiber with bound phenolic compounds from different algae

The morphological, physicochemical, and biochemical properties of soluble and insoluble dietary fiber from seven types of algae were investigated. The soluble dietary fiber (SDF) contents (6.48 to 60.90% of the total fiber) in most of the investigated algae were significantly lower than the insoluble dietary fiber (IDF) contents (39.10 to 93.52% of the total fiber). It can be inferred from the infrared and UV-Vis spectra that the SDF and IDF of algae may contain cellulose, hemicellulose, various monosaccharides, phenolic compounds, and quinone pigments. The bound phenolic in the seven algae varied widely in contents (3.76 to 14.08 mg GAE/g in IDF and 1.94 to 8.61 mg GAE/g in SDF), whose antioxidant activities in the IDF were stronger than those in SDF because of different phenolic compositions. The HPLC-mass spectrometry (MS)/MS results showed that the IDF may contain methyl-8α-hydroxy-grindelate-7β-O-7'β-ether hydrate, hydroxydecanoic acid, and malyngic acid. PRACTICAL APPLICATION: Polysaccharides of high content in algae cannot be digested by humans, hence regarded as dietary fibers. A large amount of bound phenolic compounds in dietary fibers can add to the biological activities of dietary fibers. These topics are important to the development of seaweed-based functional foods.

Macroalgae-A Sustainable Source of Chemical Compounds with Biological Activities

Nowadays, one of the most important research directions that concerns the scientific world is to exploit the earth's resources in a sustainable way. Considering the increasing interest in finding new sources of bioactive molecules and functional products, many research studies focused their interest on demonstrating the sustainability of exploiting marine macroalgal biomass as feedstock for wastewater treatment and natural fertilizer, conversion into green biofuels, active ingredients in pharmaceutical and nutraceutical products, or even for the production of functional ingredients and integration in the human food chain. The objective of the present paper was to provide an overview on the recent progress in the exploitation of different macroalgae species as a source of bioactive compounds, mainly emphasizing the latter published data regarding their potential bioactivities, health benefits, and industrial applications.

Bioactive Properties of Marine Phenolics

Phenolic compounds from marine organisms are far less studied than those from terrestrial sources since their structural diversity and variability require powerful analytical tools. However, both their biological relevance and potential properties make them an attractive group deserving increasing scientific interest. The use of efficient extraction and, in some cases, purification techniques can provide novel bioactives useful for food, nutraceutical, cosmeceutical and pharmaceutical applications. The bioactivity of marine phenolics is the consequence of their enzyme inhibitory effect and antimicrobial, antiviral, anticancer, antidiabetic, antioxidant, or anti-inflammatory activities. This review presents a survey of the major types of phenolic compounds found in marine sources, as well as their reputed effect in relation to the occurrence of dietary and lifestyle-related diseases, notably type 2 diabetes mellitus, obesity, metabolic syndrome, cancer and Alzheimer's disease. In addition, the influence of marine phenolics on gut microbiota and other pathologies is also addressed.

LC-ESI-QTOF-MS/MS Characterization of Seaweed Phenolics and Their Antioxidant Potential

Seaweed is an important food widely consumed in Asian countries. Seaweed has a diverse array of bioactive compounds, including dietary fiber, carbohydrate, protein, fatty acid, minerals and polyphenols, which contribute to the health benefits and commercial value of seaweed. Nevertheless, detailed information on polyphenol content in seaweeds is still limited. Therefore, the present work aimed to investigate the phenolic compounds present in eight seaweeds [Chlorophyta (green), Ulva sp., Caulerpa sp. and Codium sp.; Rhodophyta (red), Dasya sp., Grateloupia sp. and Centroceras sp.; Ochrophyta (brown), Ecklonia sp., Sargassum sp.], using liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS). The total phenolic content (TPC), total flavonoid content (TFC) and total tannin content (TTC) were determined. The antioxidant potential of seaweed was assessed using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, a 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical scavenging assay and a ferric reducing antioxidant power (FRAP) assay. Brown seaweed species showed the highest total polyphenol content, which correlated with the highest antioxidant potential. The LC-ESI-QTOF-MS/MS tentatively identified a total of 54 phenolic compounds present in the eight seaweeds. The largest number of phenolic compounds were present in Centroceras sp. followed by Ecklonia sp. and Caulerpa sp. Using high-performance liquid chromatography-photodiode array (HPLC-PDA) quantification, the most abundant phenolic compound was p-hydroxybenzoic acid, present in Ulva sp. at 846.083 ± 0.02 μg/g fresh weight. The results obtained indicate the importance of seaweed as a promising source of polyphenols with antioxidant properties, consistent with the health potential of seaweed in food, pharmaceutical and nutraceutical applications.

Determination of Polyphenols Using Liquid Chromatography-Tandem Mass Spectrometry Technique (LC-MS/MS): A Review

In recent years, the consumption of polyphenols has been increasing, largely due to its beneficial effects on health. They are present in a wide variety of foods, but their extraction and characterization are complicated since they are mostly in complex matrices. For this reason, the use of selective, sensitive, and versatile analytical techniques such as liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) is necessary. In this review, the most relevant studies of the last years regarding the analysis of polyphenols in different matrices by comprehensive LC–MS/MS are discussed. Relevant steps such as extraction, sample purification, and chromatographic analysis methods are emphasized. In particular, the following methodological aspects are discussed: (a) the proper selection of the extraction technique, (b) the extraction and elution solvents, (c) the purification step, (d) the selection of both stationary and mobile phases for the chromatographic separation of compounds, and (e) the different conditions for mass spectrometry. Overall, this review presents the data from the most recent studies, in a comprehensive way, thus providing and simplifying the information of the great variety of works that exist in the literature on this wide topic.

Polyphenols from Brown Seaweeds as a Potential Antimicrobial Agent in Animal Feeds

Seaweeds offer a natural source of antimicrobials that may help curb antibiotic resistance in livestock. The antibacterial activity of phlorotannin extracts isolated from two brown seaweeds Ascophyllum nodosum and Fucus serratus was tested. The mechanism of action of phlorotannin extracts against Escherichia coli O157, Salmonella agona, and Streptococcus suis was elucidated by observing cell membrane permeability and intracellular adenosine triphosphate (ATP). The two extracts were effective at killing three foodborne pathogens without negatively affecting the pig intestinal cells. A. nodosum minimum inhibitory concentration (MIC) range for the different pathogens was between 1.56 and 0.78 mg/mL, whereas F. serratus was 3.13 mg/mL for all pathogens tested. A. nodosum was found to be much more potent compared to F. serratus. The difference in potency in the seaweeds may be a result of the phlorotannins' structural linkages. The antimicrobial properties of the seaweed extracts tested may provide alternative and complementary treatments to antibiotics and zinc oxide in animal feeds. The seasonal screening was performed on both species to assess the availability of phenolics throughout the year using two quantification methods, the Folin-Ciocalteu (FC) assay and quantitative nuclear magnetic resonance (NMR). The variation between the methods highlights the challenges involved in the quantification of complex phenolic structures. However, both methods show that the phenolics are subject to seasonal variation, which may prove problematic to the animal feed industry.

Exploring Ultrasound, Microwave and Ultrasound-Microwave Assisted Extraction Technologies to Increase the Extraction of Bioactive Compounds and Antioxidants from Brown Macroalgae

This study aims to determine the influence of (1) ultrasound-assisted extraction (UAE), (2) microwave-assisted extraction (MAE) and (3) a combination of ultrasound-microwave-assisted extraction (UMAE) on the yields of fucose-sulphated polysaccharides (FSPs), total soluble carbohydrates and antioxidants extracted from A. nodosum. Scanning electron microscopy (SEM) was used to evaluate the influence of the extraction technologies on the surface of macroalgae while principal component analysis was used to assess the influence of the extraction forces on the yields of compounds. UMAE generated higher yields of compounds compared to UAE and MAE methods separately. The maximum yields of compounds achieved using UMAE were: FSPs (3533.75 ± 55.81 mg fucose/100 g dried macroalgae (dm)), total soluble carbohydrates (10408.72 ± 229.11 mg glucose equivalents/100 g dm) and phenolic compounds (2605.89 ± 192.97 mg gallic acid equivalents/100 g dm). The antioxidant properties of the extracts showed no clear trend or extreme improvements by using UAE, MAE or UMAE. The macroalgal cells were strongly altered by the application of MAE and UMAE, as revealed by the SEM images. Further research will be needed to understand the combined effect of sono-generated and microwave-induced modifications on macroalgae that will allow us to tailor the forces of extraction to target specific molecules.

Phytochemical composition, antioxidant and antiproliferative activities of Rosmarinus officinalis leaves

Phytochemicals in Rosmarinus officinalis leaves, their total phenolic content, antioxidant potential and antiproliferative activity against human prostate (DU145), colon (CT26) and cervical (HeLa 229) cancer cells were investigated. Extraction was done separately using hexane, dichloromethane, ethyl acetate and methanol. A total of 32 compounds were identified, eight of which were reported for the first time. The highest phenolic content was 476.80 ± 0.69 µg/ml for the methanolic extract which also had the highest antioxidant activity with a minimum inhibitory concentration of 5.39 ± 0.09 mg/ml. Extracts exhibited the highest toxicity against prostate cancer cells and the least against cervical cancer cells.