Anticancer Effects of Seaweed-Derived Bioactive Compounds

pH-Dependent Extraction of Antioxidant Peptides from Red Seaweed Palmaria palmata: A Sequential Approach

This study employed a diverse approach to extract antioxidant peptides from red seaweed Palmaria palmata, recognized for its comparatively high protein content. Initially, an aqueous extraction of the entire seaweed was performed, followed by enzymatic hydrolysis of the solid residues prepared from the first step. The effects of three different pH levels (3, 6, and 9) during the aqueous extraction were also examined. Results indicated that the solid fraction from the sequential extraction process contained significantly higher levels of proteins and amino acids than other fractions (p < 0.05). Furthermore, the solid fractions (IC50 ranging from 2.29 to 8.15 mg.mL-1) demonstrated significantly greater free radical scavengers than the liquid fractions (IC50 ranging from 9.03 to 10.41 mg.mL-1 or not obtained at the highest concentration tested) at both stages of extraction (p < 0.05). Among the solid fractions, those produced fractions under alkaline conditions were less effective in radical scavenging than the produced fractions under acidic or neutral conditions. The fractions with most effective metal ion chelating activity were the solid fractions from the enzymatic stage, particularly at pH 3 (IC50 = 0.63 ± 0.04 mg.mL-1) and pH 6 (IC50 = 0.89 ± 0.07 mg.mL-1), which were significantly more effective than those from the initial extraction stage (p < 0.05). Despite no significant difference in the total phenolic content between these solid fractions and their corresponding liquid fractions (3.79 ± 0.05 vs. 3.48 ± 0.02 mg.mL-1 at pH 3 and 2.43 ± 0.22 vs. 2.51 ± 0.00 mg.mL-1 at pH 6) (p > 0.05), the observed antioxidant properties may be attributed to bioactive amino acids such as histidine, glutamic acid, aspartic acid, tyrosine, and methionine, either as free amino acids or within proteins and peptides.

A Comparative Analysis of the Anti-Tumor Activity of Sixteen Polysaccharide Fractions from Three Large Brown Seaweed, Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida

Searching for natural products with anti-tumor activity is an important aspect of cancer research. Seaweed polysaccharides from brown seaweed have shown promising anti-tumor activity; however, their structure, composition, and biological activity vary considerably, depending on many factors. In this study, 16 polysaccharide fractions were extracted and purified from three large brown seaweed species (Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida). The chemical composition analysis revealed that the polysaccharide fractions have varying molecular weights ranging from 8.889 to 729.67 kDa, and sulfate contents ranging from 0.50% to 10.77%. Additionally, they exhibit different monosaccharide compositions and secondary structures. Subsequently, their anti-tumor activity was compared against five tumor cell lines (A549, B16, HeLa, HepG2, and SH-SY5Y). The results showed that different fractions exhibited distinct anti-tumor properties against tumor cells. Flow cytometry and cytoplasmic fluorescence staining (Hoechst/AO staining) further confirmed that these effective fractions significantly induce tumor cell apoptosis without cytotoxicity. qRT-RCR results demonstrated that the polysaccharide fractions up-regulated the expression of Caspase-3, Caspase-8, Caspase-9, and Bax while down-regulating the expression of Bcl-2 and CDK-2. This study comprehensively compared the anti-tumor activity of polysaccharide fractions from large brown seaweed, providing valuable insights into the potent combinations of brown seaweed polysaccharides as anti-tumor agents.

Prospecting bioactivity in Antarctic algae: A review of extracts, isolated compounds and their effects

Algae and its metabolites have been a popular subject of research in numerous fields over the years. Various reviews have been written on algal bioactive components, but a specific focus on Antarctic-derived algae is seldom reviewed. Due to the extreme climate conditions of Antarctica, it is hypothesized that the acclimatized algae may have given rise to a new set of bioactive compounds as a result of adaptation. Although most studies done on Antarctic algae are based on ecological and physiological studies, as well as in the field of nanomaterial synthesis, some studies point out the potential therapeutic properties of these compounds. As an effort to shed light on a different application of Antarctic algae, this review focuses on evaluating its different medicinal properties, including antimicrobial, anticancer, antioxidative, anti-inflammatory, and skin protective effects.

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.

Etiology of lung carcinoma and treatment through medicinal plants, marine plants and green synthesized nanoparticles: A comprehensive review

Lung cancer, a leading global cause of mortality, poses a significant public health challenge primarily linked to tobacco use. While tobacco contributes to over 90% of cases, factors like dietary choices and radiation exposure also play a role. Despite potential benefits from early detection, cancer patients face hurdles, including drug resistance, chemotherapy side effects, high treatment costs, and limited healthcare access. Traditional medicinal plant knowledge has recently unveiled diverse cancer chemopreventive agents from terrestrial and marine sources. These phytochemicals regulate intricate molecular processes, influencing the immune system, apoptosis, cell cycle, proliferation, carcinogen elimination, and antioxidant levels. In pursuing cutting-edge strategies to combat the diverse forms of cancer, technological advancements have spurred innovative approaches. Researchers have focused on the green synthesis of metallic nanoparticles using plant metabolites. This method offers distinct advantages over conventional physical and chemical synthesis techniques, such as cost-effectiveness, biocompatibility, and energy efficiency. Metallic nanoparticles, through various pathways such as the generation of reactive oxygen species, modulation of enzyme activity, DNA fragmentation, disruption of signaling pathways, perturbation of cell membranes, and interference with mitochondrial function resulting in DNA damage, cell cycle arrest, and apoptosis, exhibit significant potential for preventive applications. Thus, the amalgamation of phytocompounds and metallic nanoparticles holds promise as a novel approach to lung cancer therapy. However, further refinements and advancements are necessary to enhance the environmentally friendly process of metallic nanoparticle synthesis.

Identification of cholest-4-ene-3,6-dione as a Novel Neuroprotectant in Ischemic Stroke and Its Lipidomics

Purpose

Stroke is a leading cause of disability and death globally. However, there are few clinical drugs for stroke therapy. Novel and effective neuroprotectants are called on the way.

Methods

In this study, 93 steroids from a constructed steroidal library were randomly numbered and blindly evaluated in an L-glutamate-induced HT-22 oxidative stress model. The neuroprotective effects of 5 candidates were further investigated in potassium deprivation-induced apoptosis of cerebellar granule neurons (CGNs), D-glutamate-induced excitotoxicity of CGNs, and cortical neuron (CN) models.

Results

Interestingly, unblinding revealed that cholest-4-ene-3,6-dione (78), a cholesterol derivative, was first found to have comprehensive neuroprotective effects in all cell models. 78 administration also decreased the infarction volume and improved motor function in middle cerebral artery occlusion (MCAO) model rats. Additionally, 78 treatment decreased intercellular reactive oxygen species (ROS) and NO production in the HT-22 cell model. Finally, lipidomics and molecular docking results showed that 78 may exert its neuroprotective effects by increasing platelet-activating factor (PAF) analog 1-(9Z-pentadecenoyl)-glycero-3-phosphocholine production.

Conclusion

This study indicates that 78, a novel neuroprotectant, is a promising therapeutic candidate with comprehensive neuroprotective effects for the treatment of ischemic stroke by decreasing ROS/reactive nitrogen species (RNS) levels and increasing 1-(9Z-pentadecenoyl)-glycero-3-phospho-choline production.

Seasonal variation in the metabolome expression of Jania rubens (Rhodophyta) reveals eicosapentaenoic acid as a potential anticancer metabolite

Seaweeds of the intertidal zone are subjected to diverse stresses due to environmental changes in radiation, salinity, water quality, herbivore communities, etc. Thus, marine seaweeds developed various unique compounds to deal with environmental fluctuations. Therefore, they are a good source of unique novel compounds. Here, we explored the seasonal metabolomic changes in Jania rubens and found notable changes between extracts of different seasons in the metabolomic profile and in their anticancer activity. The most bioactive extract was from samples collected during the Fall season, which demonstrated an LC50 of 178.39 (± 10.02 SD) µg/ml toward Non Small Cell Lung Cancer (NSCLC) followed by the Winter season extract. The Fall and Winter extracts also displayed more resemblance in their metabolic profile relative to Spring and Summer extracts. The Fall extract was fractionated and tested for cytotoxic activity toward an array of cancer cell lines. Eventually, using a bio-guided assay and multiple fractionation steps, we isolated and identified the essential fatty acid, eicosapentaenoic acid, as the active anticancer agent, showing an LC50 of 5.23 (± 0.07 SD) µg/ml toward NSCLC. Our results emphasize the potential use of J. rubens as a source of beneficial fatty acids and stress the importance of environmental effects on metabolic constitutes.

Exploring Bioactive Compounds in Brown Seaweeds Using Subcritical Water: A Comprehensive Analysis

In this study, we characterized the bioactive properties of three important brown seaweed species, Sargassum thunbergii, Undaria pinnatifida, and Saccharina japonica, by subcritical water extraction (SWE), as these species are well known for their beneficial health effects. Their physiochemical properties, including potential antioxidant, antihypertensive, and α-glucosidase inhibitory activity, and the antibacterial activity of the hydroysates were also analyzed. The highest total phlorotannin, total sugar content, and reducing sugar content in the S. thunbergii hydrolysates were 38.82 ± 0.17 mg PGE/g, 116.66 ± 0.19 mg glucose/g dry sample, and 53.27 ± 1.57 mg glucose/g dry sample, respectively. The highest ABTS⁺ and DPPH antioxidant activities were obtained in the S. japonica hydrolysates (124.77 ± 2.47 and 46.35 ± 0.01 mg Trolox equivalent/g, respectively) and the highest FRAP activity was obtained in the S. thunbergii hydrolysates (34.47 ± 0.49 mg Trolox equivalent/g seaweed). In addition, the seaweed extracts showed antihypertensive (≤59.77 ± 0.14%) and α-glucosidase inhibitory activity (≤68.05 ± 1.15%), as well as activity against foodborne pathogens. The present findings provide evidence of the biological activity of brown seaweed extracts for potential application in the food, pharmaceutical, and cosmetic sectors.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Antiproliferative and apoptosis-inducing effects of aqueous extracts from Ecklonia maxima and Ulva rigida on HepG2 cells

This study examined the antiproliferative and apoptotic-inducing effects of Ecklonia maxima (KP) and Ulva rigida (URL) extracts in the human liver cancer (HepG2) cell line model. HepG2 cells were cultured and grown in an incubator (5% CO2 ) at 37°C. Cell viability was determined, while the effect of the extracts on apoptosis, ROS production, mitochondria membrane potential, and antioxidant enzymes were also assessed. KP and URL induced cytotoxic effects on HepG2 cells at the concentrations tested (0-1000 μg/ml). The morphological characteristics of the cells after treatment with KP and URL revealed cell shrinkage of the nucleus, cell injury, and damage compared to the control. The fluorescent micrographs from the apoptotic assay revealed induction of apoptosis and necrosis in HepG2 cells after treatment with KP and URL (200 and 400 μg/ml). The extracts also induced ROS production and reduced mitochondria membrane potential in HepG2 cells. The apoptotic-inducing effects, activation of ROS generation, and disruption of antioxidant enzymes are associated with the cytotoxic effects of the seaweed extracts. KP and URL showed good anticancer properties and could be explored as a good source of nutraceuticals, food additives, and dietary supplements to prevent uncontrolled proliferation of HepG2 cells. PRACTICAL APPLICATIONS: Seaweeds are reservoirs of nutrients and naturally occurring biologically active compounds, including sterols, phlorotannins, and polyunsaturated fatty acids. Due to the presence of these compounds, they are used as emulsifying agents, nutraceuticals, and additives in functional foods. Evidence suggests that seaweed bioactives may inhibit uncontrolled cell proliferation and induce apoptosis in cancer cells. Hence, exploring the antiproliferative and apoptotic-inducing effects of Ecklonia maxima and Ulva rigida will provide insights into their anticancer potentials as functional foods and nutraceuticals.

Anti-Melanogenesis and Photoprotective Effects of Ecklonia maxima Extract Containing Dieckol and Eckmaxol

Seaweeds are potential ingredients in the cosmeceutical industry. Our previous study demonstrates that the phlorotannin-enriched extract of Ecklonia maxima (EME-EA) containing dieckol and eckmaxol possesses strong anti-inflammatory activity and suggests the cosmeceutical potential of EME-EA. In order to evaluate the cosmeceutical potential of EME-EA, the anti-melanogenesis and photoprotective effects of EME-EA were investigated in this study. EME-EA remarkably inhibited mushroom tyrosinase and melanogenesis in alpha-melanocyte-stimulating hormone-stimulated B16F10 cells. In addition, EME-EA significantly suppressed UVB-induced HaCaT cell death that was consistent with inhibition of apoptosis and reduction in scavenging intracellular reactive oxygen species. Furthermore, EME-EA significantly inhibited collagen degradation and matrix metalloproteinases expression in UVB-irradiated HDF cells in a concentration-dependent manner. These results indicate that EME-EA possesses strong anti-melanogenesis and photoprotective activities and suggest EME-EA is an ideal ingredient in the pharmaceutical and cosmeceutical industries.

Recent advances in biological properties of brown algae-derived compounds for nutraceutical applications

The increasing demand for nutraceuticals in the circular economy era has driven the research toward studying bioactive compounds from renewable underexploited resources. In this regard, the exploration of brown algae has shown significant growth and maintains a great promise for the future. One possible explanation could be that brown algae are rich sources of nutritional compounds (polyunsaturated fatty acids, fiber, proteins, minerals, and vitamins) and unique metabolic compounds (phlorotannins, fucoxanthin, fucoidan) with promising biological activities that make them good candidates for nutraceutical applications with increased value-added. In this review, a deep description of bioactive compounds from brown algae is presented. In addition, recent advances in biological activities ascribed to these compounds through in vitro and in vivo assays are pointed out. Delivery strategies to overcome some drawbacks related to the direct application of algae-derived compounds (low solubility, thermal instability, bioavailability, unpleasant organoleptic properties) are also reviewed. Finally, current commercial and legal statuses of ingredients from brown algae are presented, considering future therapeutical and market perspectives as nutraceuticals.

Antitumor immunity and therapeutic properties of marine seaweeds-derived extracts in the treatment of cancer

Marine seaweeds are important sources of drugs with several pharmacological characteristics. The present study aims to evaluate the antitumor and antitumor immunological potentials of the extracts from the brown alga Padina pavonica and the red alga Jania rubens, inhibiting the Egyptian marine coasts. Hep-G2 cell lines were used for assessment of the antitumor efficacy of Padina pavonica and Jania rubens extracts in vitro, while Ehrlich ascites carcinoma (EAC) cells were applied to gain more antitumor immunity and antitumor insights of P. pavonica and J. rubens extracts in vivo. In vitro antitumor potentials of P. pavonica and J. rubens extracts were analyzed against human liver cancer Hep-G2 cells by MTT and trypan blue exclusion assays. In vivo antitumor immunological potentials of P. pavonica and J. rubens extracts at low, high, and prophylactic doses were analyzed by blood counting and flow cytometry in mice challenged with Ehrlich ascites carcinoma (EAC) cells. In vitro results revealed that P. pavonica and J. rubens extracts caused significant decreases in the number and viability of Hep-G2 cells in a dose-dependent manner as compared to untreated Hep-G2 cells or Cisplatin®-treated Hep-G2 cells. In vivo findings showed that P. pavonica and J. rubens extracts at low, high, and prophylactic doses significantly reduced the number and viability of EAC tumor cells accompanied by increases in EAC apoptosis compared to naïve EAC mouse. Additionally, P. pavonica and J. rubens extracts at low and prophylactic doses remarkably increased both the total WBC count and the relative numbers of lymphocytes and decreased the relative numbers of neutrophils and monocytes. Flow cytometric analysis showed that P. pavonica and J. rubens extracts at the treatment and the prophylactic doses resulted in a significant increase in the phenotypic expressions of CD4+ T, CD8+ T, and CD335 cells compared to naïve EAC mouse. Overall, both extracts P. pavonica and J. rubens possess potential antitumor and antitumor immunological effects with less toxicity, opening new approaches for further studies of the chemical and biological mechanisms behind these effects.

Natural Products of Marine Origin for the Treatment of Colorectal and Pancreatic Cancers: Mechanisms and Potential

Gastrointestinal cancer refers to malignancy of the accessory organs of digestion, and it includes colorectal cancer (CRC) and pancreatic cancer (PC). Worldwide, CRC is the second most common cancer among women and the third most common among men. PC has a poor prognosis and high mortality, with 5-year relative survival of approximately 11.5%. Conventional chemotherapy treatments for these cancers are limited due to severe side effects and the development of drug resistance. Therefore, there is an urgent need to develop new and safe drugs for effective treatment of PC and CRC. Historically, natural sources—plants in particular—have played a dominant role in traditional medicine used to treat a wide spectrum of diseases. In recent decades, marine natural products (MNPs) have shown great potential as drugs, but drug leads for treating various types of cancer, including CRC and PC, are scarce. To date, marine-based drugs have been used against leukemia, metastatic breast cancer, soft tissue sarcoma, and ovarian cancer. In this review, we summarized existing studies describing MNPs that were found to have an effect on CRC and PC, and we discussed the potential mechanisms of action of MNPs as well as future prospects for their use in treating these cancers.

Immunomodulatory and Antitumoral Activity of Gold Nanoparticles Synthesized by Red Algae Aqueous Extracts

This study reports on the green and cost-efficient synthesis of gold nanoparticles from three different red algae extracts. The nanoparticles synthesized were fully characterized by UV-Vis spectroscopy, HRTEM, and Z-potential. Relevant components occurring in the extracts, such as polysaccharides or phenolic content, were assessed by analytical techniques such as spectrophotometric assays and liquid chromatography. Finally, the antioxidant, antitumoral, and anti-inflammatory potential of both the extracts and the gold nanoparticles synthesized were analyzed in order to determine a possible synergistic effect on the nanoparticles. The results obtained confirmed the obtainment of gold nanoparticles with significant potential as immunotherapeutic agents. The therapeutic potential of these nanoparticles could be higher than that of inert gold nanoparticles loaded with bioactive molecules since the former would allow for higher accumulation into the targeted tissue.