Methods for isolation, purification and structural elucidation of bioactive secondary metabolites from marine invertebrates

Bioactive potency of extracts from Stylissa carteri and Amphimedon chloros with silver nanoparticles against cancer cell lines and pathogenic bacteria

Silver nanoparticles (AgNPs) are spherical particles with a number of specific and unique physical (such as surface plasmon resonance, high electrical conductivity and thermal stability) as well as chemical (including antimicrobial activity, catalytic efficiency and the ability to form conjugates with biomolecules) properties. These properties allow AgNPs to exhibit desired interactions with the biological system and make them prospective candidates for use in antibacterial and anticancer activities. AgNPs have a quenching capacity, which produces reactive oxygen species and disrupts cellular processes (such as reducing the function of the mitochondria, damaging the cell membrane, inhibiting DNA replication and altering protein synthesis). In addition, sponge extracts contain biologically active substances with therapeutic effects. Therefore, the concurrent use of these agents may present a potential for the development of novel antitumor and antimicrobial drugs. The present study investigated the cytotoxic effects of AgNPs combined with the extracts from sponge species, Stylissa carteri or Amphimedon chloros, against various cancer cell lines and pathogenic bacterial strains. The present study was novel as it provided a further understanding of the cytotoxicity and underlying mechanisms of AgNPs. Alterations in the properties, such as size, charge and polydispersity index, of the AgNPs were demonstrated after lyophilization. Scanning electron microscopy revealed submicron-sized particles. The cytotoxic potential of AgNPs across various cancer cell lines such as lung, colorectal, breast and pancreatic cancer cell lines, was demonstrated, especially when the AgNPs were combined with sponge extracts, which suggested a synergistic effect. Analysis using liquid chromatography-mass spectrometry revealed key chemical components in the extracts, and molecular docking simulations indicated potential inhibition interactions between a number of the extract components and the epidermal growth factor receptor and tyrosine kinase receptor A. Synergistic antibacterial effects against several bacterial species such as Staphylococcus xylosus, Klebsiella oxytoca, Enterobacter aerogenes, Micrococcus spp. and Escherichia coli, were observed when AgNPs were combined with sponge ethyl acetate extracts. The results of the present study suggested a potential therapeutic application of marine-derived compounds and nanotechnology in combating cancer and bacterial infections. Future research should further elucidate the mechanistic pathways and investigate the in vivo therapeutic efficacy.

Antimicrobial Potentials of Haliclona fibulata Derived Compounds for Combatting Drug-Resistant Bacterial Infections in Zebrafish Model

The rising threat of antimicrobial resistance among pathogens highlights the critical need for novel antimicrobial agents. This study explores the potential of natural products by investigating n-hexane extracts from the marine sponge Haliclona fibulata (HF) for their antibacterial efficacy. The well diffusion method of HF extract showed significant antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with inhibition zones of 20 ± 0.66, 27 ± 0.58, and 22 ± 0.33 mm, respectively. Scanning electron microscopy investigations confirmed the disruptive impact of the extracts on bacterial cell morphology. Further investigations using P. aeruginosa-infected zebrafish model revealed that HF treatment improved survival rates in a dose-dependent manner. Additionally, oxidative stress and apoptosis were significantly reduced in the 100 µg/mL (HF100) treatment group, alongside downregulation of inflammatory markers such as il-1β, nf-kβ, tnf-α, and inos. Histological assessments showed reduced intestinal damage and fewer circulating macrophages in HF100-treated zebrafish larvae. Identifying potent bioactive compounds within the extracts suggests that HF could be a valuable source of natural antimicrobials, warranting further exploration for developing treatments against pathogenic infections.

Isolation of Natural Products from Marine Invertebrates

Marine invertebrates such as sponges, cnidarians, bryozoans, and tunicates are considered to be prolific sources of novel biologically active natural products. Specimens from these organisms are composed of soft tissues with a high water and inorganic salt content compared to those from terrestrial counterparts. In addition, some of the secondary metabolites from these organisms tend to be more polar than those of terrestrial. These general characteristics have led to the establishment of differentiated protocols for metabolites derived from marine invertebrates. In this chapter, we describe an available protocol for the isolation of secondary metabolites from marine invertebrates, including extraction, fractionation, and purification procedures. While detailed protocols should be adapted to the characteristics of the specific organism being studied, the methods provided here can serve as an initial guide for designing those.

Design and evaluation of nanostructured lipid carrier of Bergenin isolated from Pentaclethra macrophylla for anti-inflammatory effect on lipopolysaccharide-induced inflammatory responses in macrophages

Herein, we report the properties of nanostructured lipid carriers (NLCs) prepared with a gradient concentration of Bergenin (BGN) isolated from Pentaclethra macrophylla stem bark powder. A gradient concentration of BGN (BGN 0, 50, 100, 150, and 200 mg) was prepared in a 5 % lipid matrix consisting of Transcutol HP (75 %), Phospholipon 90H (15 %), and Gelucire 43/01 (10 %) to which a surfactant aqueous phase consisting of Tween 80, sorbitol, and sorbic acid was dissolved. The NLCs were evaluated by size, polydispersity index (PDI), zeta potential, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), encapsulation efficiency, and in vitro drug release. The result shows polydispersed nanoparticles with high drug encapsulation (94.26-99.50 %). The nanoparticles were mostly spherical, but those from the 50 mg BGN batch were more cuboidal than spherical. The drug release was highest from the latter to the tune of 40 % compared to the pure BGN solution, which released about 15 % BGN. The anti-inflammatory activity of the BGN-NLC and total plant extract was studied on lipopolysaccharide (LPS)-inflamed macrophages. The cell study showed that BGN and plant extract had low cytotoxicity on macrophages and exhibited a dose-dependent anti-inflammatory effect on the LPS-induced inflammatory process in macrophages.

Separation Methods of Phenolic Compounds from Plant Extract as Antioxidant Agents Candidate

In recent years, discovering new drug candidates has become a top priority in research. Natural products have proven to be a promising source for such discoveries as many researchers have successfully isolated bioactive compounds with various activities that show potential as drug candidates. Among these compounds, phenolic compounds have been frequently isolated due to their many biological activities, including their role as antioxidants, making them candidates for treating diseases related to oxidative stress. The isolation method is essential, and researchers have sought to find effective procedures that maximize the purity and yield of bioactive compounds. This review aims to provide information on the isolation or separation methods for phenolic compounds with antioxidant activities using column chromatography, medium-pressure liquid chromatography, high-performance liquid chromatography, counter-current chromatography, hydrophilic interaction chromatography, supercritical fluid chromatography, molecularly imprinted technologies, and high-performance thin layer chromatography. For isolation or purification, the molecularly imprinted technologies represent a more accessible and more efficient procedure because they can be applied directly to the extract to reduce the complicated isolation process. However, it still requires further development and refinement.

An evaluation of the antioxidant potential and in vitro enzyme inhibition profile of selected bryophytes from Northeast Anatolia (Türkiye)

Interest in the use of bryophytes in pharmaceutical, cosmetic, and food industrial applications is growing worldwide due to their secondary metabolites. In this study, n-hexane crude extracts and further fractions (aqueous, ethyl acetate and n-butanol) of aqueous ethanol (80:20, ethanol:H2O, v/v) were obtained from five different bryophytes (Pellia epiphylla, Conocephalum conicum, Porella platyphylla, Plagiomnium cuspidatum and Mnium spinulosum) collected from Trabzon, Türkiye. The total phenolic compound (TPC) content, antioxidant capacity (AC) and enzyme inhibition activity (acetylcholine esterase, butyrylcholine esterase, tyrosinase, α-amylase and α-glucosidase) of the extracts and fractions were species-specific and varied significantly between the crude extracts and fractions. Among the different bryophytes, Porella platyphylla and Pellia epiphylla in n-butanol and Plagiomnium cuspidatum and Mnium spinulosum in ethyl acetate fraction exhibited the highest TPC contents and AC values. The contents of phenolic acids liberated in free, ester and glycoside forms were also species-specific. p-Hydroxybenzoic acid (p-HBA) in free form in P. cuspidatum and P. platyphylla, p-coumaric acid (p-CoA) in ester form and m-hydroxybenzoic acid (m-HBA) in glycoside form in M. spinulosum were the major phenolic acids in the bryophytes. The n-hexane extracts of the bryophytes, in particular M. spinulosum, had IC50 values ​​almost 100 times lower than acarbose. This suggests that M. spinulosum in particular may represent a possible candidate for the production of new antidiabetic agents.

Anti-fungal bioactive terpenoids in the bioenergy crop switchgrass (Panicum virgatum) may contribute to ecotype-specific microbiome composition

Plant derived bioactive small molecules have attracted attention of scientists across fundamental and applied scientific disciplines. We seek to understand the influence of these phytochemicals on rhizosphere and root-associated fungi. We hypothesize that - consistent with accumulating evidence that switchgrass genotype impacts microbiome assembly - differential terpenoid accumulation contributes to switchgrass ecotype-specific microbiome composition. An initial in vitro Petri plate-based disc diffusion screen of 18 switchgrass root derived fungal isolates revealed differential responses to upland- and lowland-isolated metabolites. To identify specific fungal growth-modulating metabolites, we tested fractions from root extracts on three ecologically important fungal isolates - Linnemania elongata, Trichoderma sp. and Fusarium sp. Saponins and diterpenoids were identified as the most prominent antifungal metabolites. Finally, analysis of liquid chromatography-purified terpenoids revealed fungal inhibition structure - activity relationships (SAR). Saponin antifungal activity was primarily determined by the number of sugar moieties - saponins glycosylated at a single core position were inhibitory whereas saponins glycosylated at two core positions were inactive. Saponin core hydroxylation and acetylation were also associated with reduced activity. Diterpenoid activity required the presence of an intact furan ring for strong fungal growth inhibition. These results inform future breeding and biotechnology strategies for crop protection with reduced pesticide application.

A New Diterpenoid of Indonesian Scoparia dulcis Linn: Isolation and Cytotoxic Activity against MCF-7 and T47D Cell Lines

Scoparia dulcis Linn plays an important role in treatment because it contains active compounds that are proven to have a variety of activities, including cytotoxicity on various cancer cells. The objective of this study is to isolate and identify the cytotoxic compounds in the ethyl acetate fraction of Scoparia dulcis, observe cell cycle inhibition and induction of apoptosis in vitro, and carry out molecular studies using in silico studies. A new diterpene compound was isolated from the ethyl acetate fraction of Scoparia dulcis L. of Indonesian origin. Chromatographic methods were used to isolate the compound, spectroscopic methods were used to elucidate its structure, and these data were compared with those reported in the literature. The compound was tested for its cytotoxic activity against two breast cancer cells (MCF-7 and T47D). The results of the isolated compound showed a cytotoxic effect on MCF-7 and T47D breast cancer cells at IC50 70.56 ± 1.54 and <3.125 ± 0.43 µg/mL, respectively. The compound inhibited the growth of MCF-7 and T47D breast cancer cells and the accumulation of cells in the G1 phases, and it induced apoptosis. Based on a spectroscopic analysis, the isolated compound was identified as 2α-hydroxyscopadiol, which is a new diterpenoid. A docking study revealed that the isolate's hydroxyl groups are essential for interacting with crucial residues on the active sites of the ER and PR and caspase-9. The isolate inhibits ER and PR activity with binding energies of -8.2 kcal/mol and -7.3 kcal/mol, respectively. In addition, the isolate was also able to induce apoptosis through the activation of the caspase-9 pathway with an affinity of -9.0 kcal/mol. In conclusion, the isolated compound from S. dulcis demonstrated anticancer activity based on in vitro and in silico studies.

Marine bioactive compounds as antibiofilm agent: a metabolomic approach

The ocean is a treasure trove of both living and nonliving creatures, harboring incredibly diverse group of organisms. A plethora of marine sourced bioactive compounds are discovered over the past few decades, many of which are found to show antibiofilm activity. These are of immense clinical significance since the formation of microbial biofilm is associated with the development of high antibiotic resistance. Biofilms are also responsible to bring about problems associated with industries. In fact, the toilets and wash-basins also show degradation due to development of biofilm on their surfaces. Antimicrobial resistance exhibited by the biofilm can be a potent threat not only for the health care unit along with industries and daily utilities. Various recent studies have shown that the marine members of various kingdom are capable of producing antibiofilm compounds. Many such compounds are with unique structural features and metabolomics approaches are essential to study such large sets of metabolites. Associating holobiome metabolomics with analysis of their chemical attribute may bring new insights on their antibiofilm effect and their applicability as a substitute for conventional antibiotics. The application of computer-aided drug design/discovery (CADD) techniques including neural network approaches and structured-based virtual screening, ligand-based virtual screening in combination with experimental validation techniques may help in the identification of these molecules and evaluation of their drug like properties.

Comparison of metabolite profiles and cytotoxicity of the black sea cucumber (Holothuria atra) dried with different drying techniques

Holothuria atra is a species of sea cucumber that could be a source of cytotoxic compounds. The present work aimed to determine the effect of different drying techniques on the profile of metabolites and cytotoxicity of sea cucumber extracts. Sea cucumbers were dried in the sun for 3 d, and then oven-dried at a temperature of 40, 50, and 60°C for 24 h. Fresh sea cucumbers without drying served as a control. The dried and fresh sea cucumbers were extracted by maceration for 12 h using ethanol. The metabolite profiling was performed using Fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) analyses, whereas the cytotoxicity was assayed by MTT method using the human breast ductal carcinoma cells (T47D). Analyses of FTIR and HPLC showed that the bioactive compounds of the ethanol extract were relatively stable during drying. This was in line with its cytotoxicity against T47D cells, which did not show significant differences between treatments. Based on these results, it was concluded that drying by sun or oven did not damage the bioactive compounds in the ethanolic extract of sea cucumber.

Combination of Medium- and High-Pressure Liquid Chromatography for Isolation of L-tryptophan (Q-marker) from Medicago sativa Extract

Medicago sativa (alfalfa) is a widely used animal feed. However, its quality has been difficult to control due to the lack of appropriate marker compounds. Therefore, it is very necessary to select an appropriate quality marker (Q-marker) to control its quality. In this study, medium-pressure liquid chromatography and high-pressure liquid chromatography were employed to effectively prepare the separation of the Q-marker (L-tryptophan) from Medicago sativa. Firstly, using MCI GEL® CHP20P as the stationary phase, 2.5 g of the target fraction Fr3 was enriched from crude Medicago sativa extract (2.9 kg) by medium-pressure liquid chromatography. Secondly, Sephadex LH-20 was used to further separate Fr3 fractions, and the Fr34 fraction (358.3 mg) was enriched after 14 repetitions. Lastly, using the ReproSil-Pur C18 AQ preparative column, 63.4 mg of L-tryptophan was obtained by high-pressure liquid chromatography, and the purity was above 95%. The results showed that medium-pressure liquid chromatography (MCI GEL® CHP20P and Sephadex LH-20) combined with high-pressure liquid chromatography (ReproSil-Pur C18 AQ) could be used to effectively prepare the Q-marker from natural products with satisfactory purity.

Antifungal and antibacterial activity of marine sponges from Ratnagiri coast of India

Marine sponges have proved to be a rich source of bioactive metabolites with multiple pharmacological properties. In this study, we have investigated the antifungal and antibacterial activities of methanol extracts of Cliona, Haliclona cratera, Hyrtios cavernosus, Spongia obscura, Sarcotragus foetidus, and Xestospongia carbonaria and fractions from X. carbonaria S. obscura and H. cratera. The antibacterial activity was determined by agar disc diffusion method against clinical gram-positive- Staphylococcus aureus, Bacillus subtilis and gram negative- Escherichia coli, Pseudomonas aeruginosa bacteria. The antifungal activity of the extracts and fractions was determined against Candida albicans and Aspergillus niger. S. obscura, X. carbonaria, H. cavernosus, and H. cratera exhibited good antibacterial activity against the tested gram-positive bacteria with larger zones of inhibition at 19±6 mm, 19.5±5.5mm, 20±0 mm and 23±0 mm. S. foetidus gave good inhibition of gram-negative bacteria at 19±0 mm. They showed moderate antifungal activities against C. albicans and A. niger. Cliona, H. cratera and H. cavernosus gave inhibition with 20±5 mm, 15.5±0.5 mm and 25.5±14.5 mm for A. niger. The MIC for Xc_PE_2, Sob_n but_1 and Hc_n but_3 was determined. H. cavernosus, S. foetidus, S. obscura and X. carbonaria showed presence of fatty acids and sterol type of compounds. The mass of molecular ions in purified fractions helped in characterization of known compounds in H. cratera, X. carbonaria and S. obscura which exhibited good antimicrobial activity.

Phytocompounds as an Alternative Antimicrobial Approach in Aquaculture

Despite culturing the fastest-growing animal in animal husbandry, fish farmers are often adversely economically affected by pathogenic disease outbreaks across the world. Although there are available solutions such as the application of antibiotics to mitigate this phenomenon, the excessive and injudicious use of antibiotics has brought with it major concerns to the community at large, mainly due to the rapid development of resistant bacteria. At present, the use of natural compounds such as phytocompounds that can be an alternative to antibiotics is being explored to address the issue of antimicrobial resistance (AMR). These phytocompounds are bioactive agents that can be found in many species of plants and hold much potential. In this review, we will discuss phytocompounds extracted from plants that have been evidenced to contain antimicrobial, antifungal, antiviral and antiparasitic activities. Further, it has also been found that compounds such as terpenes, phenolics, saponins and alkaloids can be beneficial to the aquaculture industry when applied. This review will focus mainly on compounds that have been identified between 2000 and 2021. It is hoped this review will shed light on promising phytocompounds that can potentially and effectively mitigate AMR.

Heterorhabditis and Photorhabdus Symbiosis: A Natural Mine of Bioactive Compounds

Phylum Nematoda is of great economic importance. It has been a focused area for various research activities in distinct domains across the globe. Among nematodes, there is a group called entomopathogenic nematodes, which has two families that live in symbiotic association with bacteria of genus Xenorhabdus and Photorhabdus, respectively. With the passing years, researchers have isolated a wide array of bioactive compounds from these symbiotically associated nematodes. In this article, we are encapsulating bioactive compounds isolated from members of the family Heterorhabditidae inhabiting Photorhabdus in its gut. Isolated bioactive compounds have shown a wide range of biological activity against deadly pathogens to both plants as well as animals. Some compounds exhibit lethal effects against fungi, bacteria, protozoan, insects, cancerous cell lines, neuroinflammation, etc., with great potency. The main aim of this article is to collect and analyze the importance of nematode and its associated bacteria, isolated secondary metabolites, and their biomedical potential, which can serve as potential leads for further drug discovery.

Metabolomics on the study of marine organisms

BACKGROUND

Marine ecosystems are hosts to a vast array of organisms, being among the most richly biodiverse locations on the planet. The study of these ecosystems is very important, as they are not only a significant source of food for the world but also have, in recent years, become a prolific source of compounds with therapeutic potential. Studies of aspects of marine life have involved diverse fields of marine science, and the use of metabolomics as an experimental approach has increased in recent years. As part of the "omics" technologies, metabolomics has been used to deepen the understanding of interactions between marine organisms and their environment at a metabolic level and to discover new metabolites produced by these organisms.

AIM OF REVIEW

This review provides an overview of the use of metabolomics in the study of marine organisms. It also explores the use of metabolomics tools common to other fields such as plants and human metabolomics that could potentially contribute to marine organism studies. It deals with the entire process of a metabolomic study, from sample collection considerations, metabolite extraction, analytical techniques, and data analysis. It also includes an overview of recent applications of metabolomics in fields such as marine ecology and drug discovery and future perspectives of its use in the study of marine organisms.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The review covers all the steps involved in metabolomic studies of marine organisms including, collection, extraction methods, analytical tools, statistical analysis, and dereplication. It aims to provide insight into all aspects that a newcomer to the field should consider when undertaking marine metabolomics.

The isolation of water-soluble natural products - challenges, strategies and perspectives

Covering period: up to 2019Water-soluble natural products constitute a relevant group of secondary metabolites notably known for presenting potent biological activities. Examples are aminoglycosides, β-lactam antibiotics, saponins of both terrestrial and marine origin, and marine toxins. Although extensively investigated in the past, particularly during the golden age of antibiotics, hydrophilic fractions have been less scrutinized during the last few decades. This review addresses the possible reasons on why water-soluble metabolites are now under investigated and describes approaches and strategies for the isolation of these natural compounds. It presents examples of several classes of hydrosoluble natural products and how they have been isolated. Novel stationary phases and chromatography techniques are also reviewed, providing a perspective towards a renaissance in the investigation of water-soluble natural products.

Betulin, a Newly Characterized Compound in Acacia auriculiformis Bark, Is a Multi-Target Protein Kinase Inhibitor

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/β (GSK-3 α/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

Antimicrobial Properties of Actively Purified Secondary Metabolites Isolated from Different Marine Organisms

BACKGROUND

The treatment of infection caused by pathogenic bacteria becomes one of the serious concerns globally. The failure in the treatment was found due to the exhibition of multiple resistance mechanisms against the antimicrobial agents. The emergence of resistant bacterial species has also been observed due to prolong treatment using conventional antibiotics. To combat these problems, several alternative strategies have been employed using biological and chemically synthesized compounds as antibacterial agents. Marine organisms are considered as one of the potential sources for the isolation of bioactive compounds due to the easily available, cost-effective, and eco-friendly.

METHODS

The online search methodology was adapted for the collection of information related to the antimicrobial properties of marine-derived compounds. These compound has been isolated and purified by different purification techniques, and their structure also characterized. Furthermore, the antibacterial activities have been reported by using broth microdilution as well as disc diffusion assays.

RESULTS

The present review paper describes the antimicrobial effect of diverse secondary metabolites which are isolated and purified from the different marine organisms. The structural elucidation of each secondary metabolite has also been done in the present paper, which will help for the in silico designing of the novel and potent antimicrobial compounds.

CONCLUSION

A thorough literature search has been made and summarizes the list of antimicrobial compounds that are isolated from both prokaryotic and eukaryotic marine organisms. The information obtained from the present paper will be helpful for the application of marine compounds as antimicrobial agents against different antibiotic-resistant human pathogenic bacteria.

Effect of Cocoa Bean Shell Addition on Metabolite Profile and Antioxidant Activity of Herbal Infusions

Cocoa bean shell (CBS) is a by-product with aromatic characteristics that can enhance the aroma and bioactivity of herbal infusions. This study was aimed to determine the effect of the addition of cocoa bean shell on the metabolite profile and antioxidant activity of infusions made with Ilex guayusa and Vernonanthura patens and their mixtures. Metabolite profile was analyzed by gas chromatography-mass spectrometry combined with multivariate analysis. Total polyphenol content and flavonoids were determined by the Folin-Ciocalteu method and by the flavonoid-AlCl3 complex, respectively. Antioxidant activities were measured by the decolorization assay of the 2,2-diphenyl-1-picrylhydrazyl radical and the ferric reducing antioxidant power. The results revealed that the addition of CBS increases the content of phenolic acids in the infusions (caffeic acid, 4-hydroxybenzoic acid, and pyrocatechol). Nonetheless, the antioxidant activity of the infusions decreased with the addition of CBS (16.21 to 2.74 TEAC). Carboxylic acids and derivatives, major compounds present in the infusions prepared with V. patens, were the metabolites that showed the highest correlation with the antioxidant activity. This study suggests that the infusions made with CBS present a profile of metabolites different from the infusions of I. guayusa, V. patens, and their mixtures.

Bioactive Compounds from Marine Sponges: Fundamentals and Applications

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.

Isolation and Characterization of Strain Exiguobacterium sp. KRL4, a Producer of Bioactive Secondary Metabolites from a Tibetan Glacier

Extremophilic microorganisms represent a unique source of novel natural products. Among them, cold adapted bacteria and particularly alpine microorganisms are still underexplored. Here, we describe the isolation and characterization of a novel Gram-positive, aerobic rod-shaped alpine bacterium (KRL4), isolated from sediments from the Karuola glacier in Tibet, China. Complete phenotypic analysis was performed revealing the great adaptability of the strain to a wide range of temperatures (5-40 °C), pHs (5.5-8.5), and salinities (0-15% w/v NaCl). Genome sequencing identified KRL4 as a member of the placeholder genus Exiguobacterium_A and annotation revealed that only half of the protein-encoding genes (1522 of 3079) could be assigned a putative function. An analysis of the secondary metabolite clusters revealed the presence of two uncharacterized phytoene synthase containing pathways and a novel siderophore pathway. Biological assays confirmed that the strain produces molecules with antioxidant and siderophore activities. Furthermore, intracellular extracts showed nematocidal activity towards C. elegans, suggesting that strain KRL4 is a source of anthelmintic compounds.

The genetics underlying metabolic signatures in a brown rice diversity panel and their vital role in human nutrition

Brown rice (Oryza sativa) possesses various nutritionally dense bioactive phytochemicals exhibiting a wide range of antioxidant, anti-cancer, and anti-diabetic properties known to promote various human health benefits. However, despite the wide claims made about the importance of brown rice for human nutrition the underlying metabolic diversity has not been systematically explored. Non-targeted metabolite profiling of developing and mature seeds of a diverse genetic panel of 320 rice cultivars allowed quantification of 117 metabolites. The metabolite genome-wide association study (mGWAS) detected genetic variants influencing diverse metabolic targets in developing and mature seeds. We further interlinked genetic variants on chromosome 7 (6.06-6.43 Mb region) with complex epistatic genetic interactions impacting multi-dimensional nutritional targets, including complex carbohydrate starch quality, the glycemic index, antioxidant catechin, and rice grain color. Through this nutrigenomics approach rare gene bank accessions possessing genetic variants in bHLH and IPT5 genes were identified through haplotype enrichment. These variants were associated with a low glycemic index, higher catechin levels, elevated total flavonoid contents, and heightened antioxidant activity in the whole grain with elevated anti-cancer properties being confirmed in cancer cell lines. This multi-disciplinary nutrigenomics approach thus allowed us to discover the genetic basis of human health-conferring diversity in the metabolome of brown rice.

Bioactive compounds from Octopus vulgaris ink extracts exerted anti-proliferative and anti-inflammatory effects in vitro

Underutilized marine food products such as cephalopods' ink could be sources of bioactive compounds providing health benefits. This study aimed to assess the anti-proliferative and anti-inflammatory effects from Octopus vulgaris ink extracts (hexane-, ethyl acetate-, dichloromethane- (DM), and water extracts) using human colorectal (HT-29/HCT116) and breast (MDA-MB-231) cancer cells, and LPS-challenged murine RAW 264.7 cells. Except by ethyl-acetate, all of the extracts exhibited anti-proliferative effects without being cytotoxic to ARPE-19 and RAW 264.7 cells. Among DM fractions (F1/F2/F3), DM-F2 showed the highest anti-proliferative effect (LC₅₀ = 52.64 μg/mL), inducing pro-apoptotic morphological disruptions in HCT116 cells. On RAW 264.7 cells, DM-F2 displayed the lowest nitrites reduction and up-regulation of key-cytokines from the JAK-STAT, PI3K-Akt, and IL-17 pathways. Compared to control, DM-F2 increased IL-4 and decreased NF-κB fluorometric expression in peripheral blood mononuclear cells (PBMCs). Metabolomic analysis of DM-F2 highlighted hexadecanoic acid and 1-(15-methyl-1-oxohexadecyl)-pyrrolidine as the most important metabolites. These compounds also exhibited high in silico binding affinity (-4.6 to -5.8 kcal/mol) to IL-1α, IL-1β, and IL-2. Results suggested the joint immuno-modulatory and anti-proliferative effect derived from selected compounds of underutilized marine food products such as ink. This is the first report of such biological activities in extracts from O. vulgaris ink.

Octopus vulgaris ink extracts exhibit antioxidant, antimutagenic, cytoprotective, antiproliferative, and proapoptotic effects in selected human cancer cell lines

Cancer is a noncommunicable disease of rising worldwide concern. Marine food products such as Octopus vulgaris ink (OI) could be sources of compounds addressing these concerns. This study aimed to evaluate the antimutagenic, cytoprotective, antiproliferative, proapoptotic, and antioxidant capacity of OI extracts on human cancer cell lines (22Rv1, HeLa, A549). The ARPE-19 cell line was used as a reference human cell line to evaluate the ink's cytotoxicity. The water extract exhibited the highest antimutagenic and cytoprotective effect, but the dichloromethane extract (DM) showed the lowest half lethal concentration against 22Rv1 cells. Structural elucidation of purified DM fractions (F1, F2, F3) identified an unreported compound, N-(2-ozoazepan-3-yl)-pyrrolidine-2-carboxamide (OPC). DM-F2 showed high antiproliferative effect (LC₅₀ = 27.6 µg/mL), reactive species modulation, early-apoptosis induction (42.9%), and nuclei disruption in 22Rv1 cells. In silico analysis predicted high OPC affinity with Cyclin D1 (-6.70 kcal/mol), suggesting its potential impact on cell cycle arrest. These results highlight the antimutagenic, cytoprotective, and antiproliferative potential health benefits derived from underutilized marine food products such as OI. Further investigations at in vitro or in vivo levels are required to elucidate mechanisms and health benefits from OI. PRACTICAL APPLICATION: O. vulgaris ink is an underutilized marine natural product that could be a source of biological compounds with potential health benefits such as antioxidant activity and cancer prevention.

Immunnostimulatory activity of Holothuria atra sea cucumber

Immunostimulant is a substance that can stimulate the immune system against pathogenic microbes. Natural products produced by sea cucumbers have the potential to be developed as immunostimulants. This study was aimed to evaluate the imunostimulatory activity of Holothuria atra extract using the phagocytocyte assay of macrophage cells and the differentiation of leukocyte in rats. The samples of H. atra were taken from Halmahera waters, North Maluku, Indonesia. Extraction was carried out with 96% ethanol. Phagocytocyte activity assay was carried out using macrophage cells isolated from Balb/c mice (Mus musculus) using a series of doses 0.5; 1.0; 2.0; 4.0; 8.0; 16.0 and 32.0 mg/kg body weight. Leukocyte differentiation test in vivo was conducted using Rattus norvegicus rat treated with H. atra extract for 90 days with the following series of doses: 0, 25, 50, 100, and 200 mg/kg body weight. The results showed that the highest phagocytosis activity was reached at a concentration of 4.0 µg/ml, but it was insignificantly different from the negative control group (p &lt; 0.05). Leukocyte differentiation assay showed that the administration of H. atra extract increased the immune system response in the animals which was characterized by the increasing number of lymphocyte cells. H. atra extract also decreased the number of monocytes and neutrophils, suggesting the suppression of inflammation in the tested rats. Extract administration for 90 days did not cause a hypersensitivity reaction as indicated by the unchanged number of eosinophil and basophil cells. Based on the results of this study, it is concluded that H. atra had a potency to develop as an immunostimulant.

Microbial Natural Products in Drug Discovery

Over a long period of time, humans have explored many natural resources looking for remedies of various ailments. Traditional medicines have played an intrinsic role in human life for thousands of years, with people depending on medicinal plants and their products as dietary supplements as well as using them therapeutically for treatment of chronic disorders, such as cancer, malaria, diabetes, arthritis, inflammation, and liver and cardiac disorders. However, plant resources are not sufficient for treatment of recently emerging diseases. In addition, the seasonal availability and other political factors put constrains on some rare plant species. The actual breakthrough in drug discovery came concurrently with the discovery of penicillin from Penicillium notatum in 1929. This discovery dramatically changed the research of natural products and positioned microbial natural products as one of the most important clues in drug discovery due to availability, variability, great biodiversity, unique structures, and the bioactivities produced. The number of commercially available therapeutically active compounds from microbial sources to date exceeds those discovered from other sources. In this review, we introduce a short history of microbial drug discovery as well as certain features and recent research approaches, specifying the microbial origin, their featured molecules, and the diversity of the producing species. Moreover, we discuss some bioactivities as well as new approaches and trends in research in this field.

Marine sponges Sarcotragus foetidus, Xestospongia carbonaria and Spongia obscura constituents ameliorate IL-1 β and IL-6 in lipopolysaccharide-induced RAW 264.7 macrophages and carrageenan-induced oedema in rats

Marine sponges are prolific producers of an array of diverse chemical structures containing compounds with multiple biological activities. In this study, whole methanol extracts and fractionated compounds from three marine sponges namely Xestospongia carbonaria, Sarcotragus foetidus and Spongia obscura were thoroughly investigated for their antibacterial, antifungal, antioxidant and anti-inflammatory activities. Methanol extracts and fractionated compounds were characterised using high performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. Extracts were checked for cytotoxicity in RAW macrophages by MTT assay, before using them for the treatment study. Enzyme linked immunosorbent assay kits were used to check the effects on inflammatory mediator's levels (PGE₂, COX-2, IL-6, IL-1β, TNF-α) in vitro. The results demonstrated good anti-inflammatory activity of all the three marine sponges; X. carbonaria, S. foetidus and S. obscura suppressed the levels of anti-inflammatory cytokines in vitro. Reverse transcriptase-polymerase chain reaction confirmed the inhibition of IL-1β and IL-6 genes expression by the isolates of X. carbonaria and S. foetidus, while reducing cytokine levels in lipopolysaccharide-induced inflammation in vitro as well as in carrageenan-induced inflammation in rats. Two semi pure compounds isolated from X. carbonaria and S. foetidus also confirmed suppression of IL-1β and IL-6 genes expression in RAW macrophages.

Anti-Fouling Effects of Saponin-Containing Crude Extracts from Tropical Indo-Pacific Sea Cucumbers

Sea cucumbers are bottom dwelling invertebrates, which are mostly found on subtropical and tropical sea grass beds, sandy reef flats, or reef slopes. Although constantly exposed to fouling communities in these habitats, many species are surprisingly free of invertebrate epibionts and microfouling algae such as diatoms. In our study, we investigated the anti-fouling (AF) activities of different crude extracts of tropical Indo-Pacific sea cucumber species against the fouling diatom Cylindrotheca closterium. Nine sea cucumber species from three genera (i.e., Holothuria, Bohadschia, Actinopyga) were selected and extracted to assess their AF activities. To verify whether the sea cucumber characteristic triterpene glycosides were responsible for the observed potent AF activities, we tested purified fractions enriched in saponins isolated from Bohadschia argus, representing one of the most active anti-fouling extracts. Saponins were quantified by vanillin-sulfuric acid colorimetric assays and identified by LC-MS and LC-MS/MS analyses. We were able to demonstrate that AF activities in sea cucumber extracts were species-specific, and growth inhibition as well as attachment of the diatom to surfaces is dependent on the saponin concentration (i.e., Actinopyga contained the highest quantities), as well as on the molecular composition and structure of the present saponins (i.e., Bivittoside D derivative was the most bioactive compound). In conclusion, the here performed AF assay represents a promising and fast method for selecting the most promising bioactive organism as well as for identifying novel compounds with potent AF activities for the discovery of potentially novel pharmacologically active natural products.

Metabolomic study of soft corals from the Colombian Caribbean: PSYCHE and 1H-NMR comparative analysis

Marine organisms have evolved to survive against predators in complex marine ecosystems via the production of chemical compounds. Soft corals (Cnidaria, Anthozoa, Octocorallia) are an important source of chemically diverse metabolites with a broad spectrum of biological activities. Herein, we perform a comparative study between high-resolution proton nuclear magnetic resonance (1H-NMR) and pure shift yielded by chirp excitation (PSYCHE) experiments to analyze the metabolic profile of 24 soft corals from the Colombian Caribbean to correlate chemical fingerprints with their cytotoxic activity against three cancer cell lines (human cervical carcinoma (SiHa), human prostatic carcinoma (PC3) and human lung adenocarcinoma (A549)). All data obtained were explored using multivariate analysis using principal components analysis (PCA) and orthogonal partial least squares (OPLS) analysis. The results did not show a significant correlation between clusters using 1H-NMR data in the PCA and OPLS-DA models and therefore did not provide conclusive evidence; on the other hand, a metabolomic analysis of PSYCHE data obtained under the same parameters revealed that when a decoupled experiment is performed, it was possible to establish a statistically valid correlation between the chemical composition of soft corals and their cytotoxic activity against the PC3 cancer cell line, where the asperdiol and plexaurolone markers were putatively identified and related to the cytotoxic activity presented by extracts of Plexaurella sp. and Plexaura kukenthali, respectively. These results increase the speed, effectiveness and reliability of analyses for the study of this type of complex matrices.

Physicochemical characterization and antioxidant activity of sulphated polysaccharides derived from Porphyra haitanensis

This study was designed to fully characterize Porphyra haitanensis polysaccharides, and to evaluate their antioxidant activity. The polysaccharides primarily contained galactose and 3,6-anhydrogalactose in a molar ratio of 1.2:1.0, respectively and sulfate content about 3.8%. The molecular weight of polysaccharides is 2.5 × 10⁵ Da. Scanning electron microscopy and atomic force microscopy of the polysaccharides pointed towards an irregular network with more or less hexagonal and a few rectangular pores. The chemical structure was confirmed through Fourier transform infrared spectroscopy, and 1D and 2D nuclear magnetic resonance structural characterization wherein → 4-3,6-anhydro-α-L-galactopyranose-(1 → 3)-β-D-galactopyranose segments. The extracted polysaccharides revealed relatively high 2, 2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity (53.16% at 2 mg/mL), moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging efficacy (34.63% at 2 mg/mL), and low hydroxyl radical scavenging potential (23.80% at 2 mg/mL). Further purification of these polysaccharides, hence, is advised for their potential role as antioxidants in the food, pharmaceutical and cosmeceutical industry.

Inhibition of Glycation-Induced Aggregation of Human Serum Albumin by Organic-Inorganic Hybrid Nanocomposites of Iron Oxide-Functionalized Nanocellulose

Protein aggregation leads to the transformation of proteins from their soluble form to the insoluble amyloid fibrils and these aggregates get deposited in the specific body tissues, accounting for various diseases. To prevent such an aggregation, organic-inorganic hybrid nanocomposites of iron oxide nanoparticle (NP, ∼6.5-7.0 nm)-conjugated cellulose nanocrystals (CNCs) isolated from Syzygium cumini (SC) and Pinus roxburghii (PR) were chemically synthesized. Transmission electron microscopy (TEM) images of the nanocomposites suggested that the in situ-synthesized iron oxide NPs were bound to the CNC surface in a uniform and regular fashion. The ThT fluorescence assay together with 8-anilino-1-naphthalenesulfonic acid, Congo Red, and CD studies suggested that short fiber-based SC nanocomposites showed better inhibition as well as dissociation of human serum albumin aggregates. The TEM and fluorescence microscopy studies supported similar observations. Native polyacrylamide gel electrophoresis results documented dissociation of higher protein aggregates in the presence of the developed nanocomposite. Interestingly, the dissociated proteins retained their biological function by maintaining a high amount of α-helix content. The in vitro studies with HEK-293 cells suggested that the developed nanocomposite reduces aggregation-induced cytotoxicity by intracellular reactive oxygen species scavenging and maintaining the Ca2+ ion-channel. These results indicated that the hybrid organic-inorganic nanocomposite, with simultaneous sites for hydrophobic and hydrophilic interactions, tends to provide a larger surface area for nanocomposite-protein interactions, which ultimately disfavors the nucleation step for fibrillation for protein aggregates.

Understanding glycaemic control and current approaches for screening antidiabetic natural products from evidence-based medicinal plants

Type 2 Diabetes Mellitus has reached epidemic proportions as a result of over-nutrition and increasingly sedentary lifestyles. Current therapies, although effective, are not without limitations. These limitations, the alarming increase in the prevalence of diabetes, and the soaring cost of managing diabetes and its complications underscores an urgent need for safer, more efficient and affordable alternative treatments. Over 1200 plant species are reported in ethnomedicine for treating diabetes and these represents an important and promising source for the identification of novel antidiabetic compounds. Evaluating medicinal plants for desirable bioactivity goes hand-in-hand with methods in analytical biochemistry for separating and identifying lead compounds. This review aims to provide a comprehensive summary of current methods used in antidiabetic plant research to form a useful resource for researchers beginning in the field. The review summarises the current understanding of blood glucose regulation and the general mechanisms of action of current antidiabetic medications, and combines knowledge on common experimental approaches for screening plant extracts for antidiabetic activity and currently available analytical methods and technologies for the separation and identification of bioactive natural products. Common in vivo animal models, in vitro models, in silico methods and biochemical assays used for testing the antidiabetic effects of plants are discussed with a particular emphasis on in vitro methods such as cell-based bioassays for screening insulin secretagogues and insulinomimetics. Enzyme inhibition assays and molecular docking are also highlighted. The role of metabolomics, metabolite profiling, and dereplication of data for the high-throughput discovery of novel antidiabetic agents is reviewed. Finally, this review also summarises sample preparation techniques such as liquid-liquid extraction, solid phase extraction, and supercritical fluid extraction, and the critical function of nuclear magnetic resonance and high resolution liquid chromatography-mass spectrometry for the dereplication, putative identification and structure elucidation of natural compounds from evidence-based medicinal plants.

Anti-Inflammatory Effects of 5α,8α-Epidioxycholest-6-en-3β-ol, a Steroidal Endoperoxide Isolated from Aplysia depilans, Based on Bioguided Fractionation and NMR Analysis

Sea hares of Aplysia genus are recognized as a source of a diverse range of metabolites. 5α,8α-Endoperoxides belong to a group of oxidized sterols commonly found in marine organisms and display several bioactivities, including antimicrobial, anti-tumor, and immunomodulatory properties. Herein we report the isolation of 5α,8α-epidioxycholest-6-en-3β-ol (EnP(5,8)) from Aplysia depilans Gmelin, based on bioguided fractionation and nuclear magnetic resonance (NMR) analysis, as well as the first disclosure of its anti-inflammatory properties. EnP(5,8) revealed capacity to decrease cellular nitric oxide (NO) levels in RAW 264.7 macrophages treated with lipopolysaccharide (LPS) by downregulation of the Nos2 (inducible nitric oxide synthase, iNOS) gene. Moreover, EnP(5,8) also inhibited the LPS-induced expression of cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) at the mRNA and protein levels. Mild selective inhibition of COX-2 enzyme activity was also evidenced. Our findings provide evidence of EnP(5,8) as a potential lead drug molecule for the development of new anti-inflammatory agents.

A controlled aquarium system and approach to study the role of sponge-bacteria interactions using Aplysilla rosea and Vibrio natriegens

Sponge-bacteria interactions are very important due to their ecological and biological significance. To understand the impact of interactions between sponges and bacteria (both associated with and external to sponges) on sponge-associated microbial diversity, sponge metabolite profiles and bioactivity, we used a controlled aquarium system and designed an experimental approach that allows the study of sponge-bacteria interactions in a well-defined manner. To test the feasibility of this approach, this system was used to study the interaction between a sponge Aplysilla rosea and a marine bacterium commonly found in seawater, Vibrio natriegens. Sponge explants were exposed to V. natriegens, at 5 × 106 cfu/ml, and changes were monitored for 48 hours. Pyro-sequencing revealed significant shifts in microbial communities associated with the sponges after 24 to 48 hours. Both the control (sponge only without added bacteria) and Vibrio-exposed sponges showed a distinct shift in bacterial diversity and abundance with time. Vibrio exposure significantly increased bacterial diversity, the abundance of a number of taxa compared to control sponges. The result experimentally supports the notion of dynamic and concerted responses by the sponge when interacting with a bacterium, and demonstrates the feasibility of using this controlled aquarium system for the study of sponge-bacteria interactions.

Collection, Culturing, and Genome Analyses of Tropical Marine Filamentous Benthic Cyanobacteria

Decreasing sequencing costs has sparked widespread investigation of the use of microbial genomics to accelerate the discovery and development of natural products for therapeutic uses. Tropical marine filamentous cyanobacteria have historically produced many structurally novel natural products, and therefore present an excellent opportunity for the systematic discovery of new metabolites via the information derived from genomics and molecular genetics. Adequate knowledge transfer and institutional know-how are important to maintain the capability for studying filamentous cyanobacteria due to their unusual microbial morphology and characteristics. Here, we describe workflows, procedures, and commentary on sample collection, cultivation, genomic DNA generation, bioinformatics tools, and biosynthetic pathway analysis concerning filamentous cyanobacteria.

Profiling of Heterobranchia Sea Slugs from Portuguese Coastal Waters as Producers of Anti-Cancer and Anti-Inflammatory Agents

Bioprospection of marine invertebrates has been predominantly biased by the biological richness of tropical regions, thus neglecting macro-organisms from temperate ecosystems. Species that were not the object of studies on their biochemical composition include the Heterobranchia gastropods Armina maculata, Armina tigrina and Aglaja tricolorata, inhabitants of the Portuguese Atlantic coastal waters. Here, we present for the first time the fatty acid profile of neutral lipids and homarine content of these three species. Qualitative and quantitative differences in the fatty acid content among species points to the existence of a fatty acid profile of neutral lipids, particularly of each genus. The results from cytotoxicity assays, using the acetonic extracts of the gastropods on human gastric adenocarcinoma (AGS) and human lung adenocarcinoma (A549) cell lines, revealed a pronounced cytotoxic effect of the A. tigrina extract on both cell lines (IC₅₀ values of 68.75 and 69.77 μg mL⁻¹ for AGS and A549, respectively). It is worth noting the significant reduction of NO levels in LPS-challenged RAW 264.7 macrophages exposed to A. tricolorata extract, at concentrations as low as 125 μg mL⁻¹.

Light-triggered dissociation of self-assembled β-amyloid aggregates into small, nontoxic fragments by ruthenium (II) complex

The self-assembly of β-amyloid (Aβ) peptides into highly stable plaques is a major hallmark of Alzheimer's disease. Here, we report visible light-driven dissociation of β-sheet-rich Aβ aggregates into small, nontoxic fragments using ruthenium (II) complex {[Ru(bpy)₃]²⁺} that functions as a highly sensitive, biocompatible, photoresponsive anti-Aβ agent. According to our multiple analyses using thioflavin T, bicinchoninic acid, dynamic light scattering, atomic force microscopy, circular dichroism, and Fourier transform infrared spectroscopy, [Ru(bpy)₃]²⁺ successfully disassembled Aβ aggregates by destabilizing the β-sheet secondary structure under illumination of white light-emitting diode light. We validated that photoexcited [Ru(bpy)₃]²⁺ causes oxidative damages of Aβ peptides, resulting in the dissociation of Aβ aggregates. The efficacy of [Ru(bpy)₃]²⁺ is attributed to reactive oxygen species, such as singlet oxygen, generated from [Ru(bpy)₃]²⁺ that absorbed photon energy in the visible range. Furthermore, photoexcited [Ru(bpy)₃]²⁺ strongly inhibited the self-assembly of Aβ monomers even at concentrations as low as 1 nM and reduced the cytotoxicity of Aβ aggregates.

STATEMENT OF SIGNIFICANCE

Alzheimer's disease is the most common progressive neurodegenerative disease, affecting more than 13% of the population over age 65. Over the last decades, researchers have focused on understanding the mechanism of amyloid formation, the hallmark of various amyloid diseases including Alzheimer's and Parkinson's. In this paper, we successfully demonstrate the dissociation of β-Amyloid (Aβ) aggregates into small, less-amyloidic fragments by photoexcited [Ru(bpy)₃]²⁺ through destabilization of β-sheet secondary structure. We validated the light-triggered dissociation of amyloid structure using multiple analytical tools. Furthermore, we confirmed that photoexcited [Ru(bpy)₃]²⁺ reduces cytotoxicity of Aβ aggregates. Our work should open a new horizon in the study of Alzheimer's amyloid aggregation by showing the potential of photoexcited dye molecules as an alternative therapeutic strategy for treating Alzheimer's disease in future.

Anti-proliferation and Apoptosis Induction of Aqueous Leaf Extract of Carica papaya L. on Human Breast Cancer Cells MCF-7

BACKGROUND AND OBJECTIVE

Breast cancer is the most frequently diagnosed cancer in women. Chemotherapy is the main method of breast cancer treatment but there are side effects. Carica papaya leaves is vegetable foods consumed by most people of Indonesia have potential as anticancer. The aim of this study was to investigate anti-proliferative and apoptotic induced effect of aqueous papaya leaves extracts on human breast cancer cell lines MCF-7.

MATERIALS AND METHODS

Inhibitory on cell proliferation was measured by MTT assay while apoptosis induction was measured using Annexin V.

RESULTS

The results showed that papaya leaf can inhibit the proliferation of human breast cancer cells MCF-7 with IC50 in 1319.25 μg mL-1. The IC50 values of papaya leaf extract was higher than the IC50 value quercetin and doxorubicin. Papaya leaf extract can also induce apoptosis of breast cancer cells MCF-7 about 22.54% for concentration 659.63 μg mL-1 and about 20.73% for concentration 329.81 μg mL-1. The percentage of cell apoptosis of papaya leaf extract lower than doxorubicin but higher than quercetin.

CONCLUSION

This study indicated that papaya leaf extract have potential as anticancer through mechanism anti-proliferation and apoptosis induction.

Microbial consortia: a critical look at microalgae co-cultures for enhanced biomanufacturing

Monocultures have been the preferred production route in the bio-industry, where contamination has been a major bottleneck. In nature, microorganisms usually exist as part of organized communities and consortia, gaining benefits from co-habitation, keeping invaders at bay. There is increasing interest in the use of co-cultures to tackle contamination issues, and simultaneously increase productivity and product diversity. The feasibility of extending the natural phenomenon of co-habitation to the biomanufacturing industry in the form of co-cultures requires careful and systematic consideration of several aspects. This article will critically examine and review current work on microbial co-cultures, with the intent of examining the concept and proposing a design pipeline that can be developed in a biomanufacturing context.

Strategies to diversify natural products for drug discovery

Natural product libraries contain specialized metabolites derived from plants, animals, and microorganisms that play a pivotal role in drug discovery due to their immense structural diversity and wide variety of biological activities. The strategies to greatly extend natural product scaffolds through available biological and chemical approaches offer unique opportunities to access a new series of natural product analogues, enabling the construction of diverse natural product-like libraries. The affordability of these structurally diverse molecules has been a crucial step in accelerating drug discovery. This review provides an overview of various approaches to exploit the diversity of compounds for natural product-based drug development, drawing upon a series of examples to illustrate each strategy.

Field-Effect Biosensors for On-Site Detection: Recent Advances and Promising Targets

There is an explosive interest in the immediate and cost-effective analysis of field-collected biological samples, as many advanced biodetection tools are highly sensitive, yet immobile. On-site biosensors are portable and convenient sensors that provide detection results at the point of care. They are designed to secure precision in highly ionic and heterogeneous solutions with minimal hardware. Among various methods that are capable of such analysis, field-effect biosensors are promising candidates due to their unique sensitivity, manufacturing scalability, and integrability with computational circuitry. Recent developments in nanotechnological surface modification show promising results in sensing from blood, serum, and urine. This report gives a particular emphasis on the on-site efficacy of recently published field-effect biosensors, specifically, detection limits in physiological solutions, response times, and scalability. The survey of the properties and existing detection methods of four promising biotargets, exosomes, bacteria, viruses, and metabolites, aims at providing a roadmap for future field-effect and other on-site biosensors.

Toxicity, teratogenicity and antibacterial activity of posterior salivary gland (PSG) toxin from the cuttlefish Sepia pharaonis (Ehrenberg, 1831)

Toxins from the posterior salivary gland (PSG) of cuttlefishes are known toxins with pronounced toxicity. In the present study, ionic peptide rich PSG toxin from the cuttlefish S. pharaonis was isolated by ion exchange chromatography and purified by Reversed Phase High Performance Liquid Chromatography (RP-HPLC), with active fraction at a retention time of 26min. The net protein content of the PSG toxin was estimated to be 46.6mg at a proximate molecular weight of∼50kDa. Fourier Transform Infrared Spectroscopy (FT-IR) of PSG toxin revealed the presence of alcoholic OH, primary NH, alkyl CH and conjugated CONH functional groups. Circular Dichroism (CD) spectroscopy and K2D analysis of the PSG toxin confirmed the presence of secondary structure with 36.77% α-helix,12.31% β sheet and 50.92% random coil. Scanning Electron Microscopy (SEM) of the PSG toxin eluted amberlite IRA 900 Cl^- resin showed surface abrasion and corrosive blebbing. Energy Dispersive X-ray Spectrometry (EDX) analysis of PSG toxin treated resin revealed increase in nitrogen and sulphur content corresponding to amino acid composition. Teratogenicity of PSG toxin against Zebrafish embryo demonstrated developmental malformations and premature hatching at a maximum tolerated dose of 1.25μM. The PSG toxin (50μM) exhibited commendable inhibitory activity with pronounced zone of inhibition against gram E. coli (10mm) and K. pneumonia (10mm). The results strongly demonstrate the toxicity of the ionic peptide rich PSG toxin from S. pharaonis and its exploitation for its promise as a potential antibacterial agent of the future.