Antioxidant compounds from microbial sources: A review

Hydroxyl-Amide Alkaloids from Pepper Roots: Potential Sources of Natural Antioxidants and Tyrosinase Inhibitors

Pepper (Piper nigrum L.) is a widely used spice plant known for its fruits and roots, which serve as flavor enhancers in culinary applications and hold significant economic value. Despite the popularity of pepper fruits, their roots remain relatively understudied, with limited research conducted on their bioactive components. This study focused on discovering and separating the primary bioactive amide alkaloids found in pepper roots. The process involved using the antioxidant activity of crude fractions and the Global Natural Products Social Molecular Networking analysis platform. The process led to the discovery of 23 previously unknown hydroxyl-amide alkaloids. Notably, compounds 11, 12, and 14 showed excellent antioxidant activity, while compound 11 exhibited significant inhibitory effects on mushroom tyrosinase. Theoretical exploration of enzyme-ligand interactions was conducted through molecular docking and molecular dynamics simulation. The findings of this study highlight the potential of hydroxyl-amide alkaloids as antioxidant products and natural food preservatives in the pharmaceutical and food cosmetic industries.

Exploring the antimicrobial and antioxidant properties of Lentzea flaviverrucosa strain E25-2 isolated from Moroccan forest soil

The alarming rise in antimicrobial resistance (AMR) has created a significant public health challenge, necessitating the discovery of new therapeutic agents to combat infectious diseases and oxidative stress-related disorders. The Lentzea flaviverrucosa strain E25-2, isolated from Moroccan forest soil, represents a potential avenue for such research. This study aimed to identify the isolate E25-2, obtained from soil in a cold Moroccan ecosystem, and further investigate its antimicrobial and antioxidant activities. Phylogenetic analysis based on 16S rRNA gene sequences revealed the strain's classification within the Lentzea genus, with a sequence closely resembling that of Lentzea flaviverrucosa AS4.0578 (96.10% similarity). Antimicrobial activity in solid media showed moderate to strong activity against Staphylococcus aureus ATCC 25923, Bacillus cereus strain ATCC 14579, Escherichia coli strain ATCC 25922, Candida albicans strain ATCC 60193 and 4 phytopathogenic fungi. In addition, ethyl acetate extract of this isolate demonstrated potent antimicrobial activity against 7 clinically multi-drug resistant bacteria. Furthermore, it demonstrated antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals, as well as a significant increase in ferric reducing antioxidant power. A significant positive correlation was observed between antioxidant activities and total content of phenolic compounds (p < 0.0001), along with flavonoids (p < 0.0001). Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of amines, hydroxyl groups, pyridopyrazinone rings, esters and pyrrolopyrazines. The Lentzea genus could offer promising prospects in the fight against antibiotic resistance and in the prevention against oxidative stress related diseases.

Optimization of fermentation parameters to improve the biosynthesis of selenium nanoparticles by Bacillus licheniformis F1 and its comprehensive application

BACKGROUND

Selenium nanoparticles (SeNPs) are increasingly gaining attention due to its characteristics of low toxicity, high activity, and stability. Additionally, Bacillus licheniformis, as a probiotic, has achieved remarkable research outcomes in diverse fields such as medicine, feed processing, and pesticides, attracting widespread attention. Consequently, evaluating the activity of probiotics and SeNPs is paramount. The utilization of probiotics to synthesize SeNPs, achieving large-scale industrialization, is a current hotspot in the field of SeNPs synthesis and is currently the most promising synthetic method. To minimize production costs and maximize yield of SeNPs, this study selected agricultural by-products that are nutrient-rich, cost-effective, and readily available as culture medium components. This approach not only fulfills industrial production requirements but also mitigates the impact on downstream processes.

RESULTS

The experimental findings revealed that SeNPs synthesized by B. licheniformis F1 exhibited a spherical morphology with diameters ranging from 110 to 170 nm and demonstrating high stability. Both the secondary metabolites of B. licheniformis F1 and the synthesized SeNPs possessed significant free radical scavenging ability. To provide a more robust foundation for acquiring large quantities of SeNPs via fermentation with B. licheniformis F1, key factors were identified through single-factor experiments and response surface methodology (RSM) include a 2% seed liquid inoculum, a temperature of 37 ℃, and agitation at 180 rpm. Additionally, critical factors during the optimization process were corn powder (11.18 g/L), soybean meal (10.34 g/L), and NaCl (10.68 g/L). Upon validating the optimized conditions and culture medium, B. licheniformis F1 can synthesize nearly 100.00% SeNPs from 5 mmol/L sodium selenite. Subsequently, pilot-scale verification in a 5 L fermentor using the optimized medium resulted in a shortened fermentation time, significantly reducing production costs.

CONCLUSION

In this study, the efficient production of SeNPs by the probiotic B. licheniformis F1 was successfully achieved, leading to a significant reduction in fermentation costs. The exploration of the practical applications of this strain holds significant potential and provides valuable guidance for facilitating the industrial-scale implementation of microbial synthesis of SeNPs.

Diving into freshwater microbial metabolites: Pioneering research and future prospects

In practically every facet of life, especially nutrition, agriculture, and healthcare, microorganisms offer a prospective origin for abundant natural substances and products. Among these microorganisms, bacteria also possess the capability to rapidly acclimate to diverse environments, utilize varied resources, and effectively respond to environmental fluctuations, including those influenced by human activities like pollution and climate change. The ever-changing environment of freshwater bodies influences bacterial communities, offering opportunities for improving health and environmental conservation that remain unexplored. Herein, the study discusses the bacterial taxa along with specialised metabolites with antioxidant, antibacterial, and anticancer activity that have been identified from freshwater environments, thus achieving Sustainable Development Goals addressing health and wellbeing (SDG-3), economic growth (SDG-8) along with industrial development (SDG-9). The present review is intended as a compendium for research teams working in the fields of medicinal chemistry, organic chemistry, clinical research, and natural product chemistry.

Mushroom oils: A review of their production, composition, and potential applications

This review delves into the world of mushroom oils, highlighting their production, composition, and versatile applications. Despite mushrooms' overall low lipid content, their fatty acid composition, rich in essential fatty acids like linoleic acid and oleic acid, proves nutritionally significant. Variations in fatty acid profiles across mushroom species and the prevalence of unsaturated fats contribute to their cardiovascular health benefits. The exploration extends to mushroom essential oils, revealing diverse volatile compounds through extraction methods like hydrodistillation and solvent-assisted flavor evaporation (SAFE). The identification of 1-octen-3-ol as a key contributor to the distinct "mushroom flavor" adds a nuanced perspective. The focus broadens to applications, encompassing culinary and industrial uses with techniques like cold pressing and supercritical fluid extraction (SFE). Mushroom oils, with their unique nutritional and flavor profiles, enhance gastronomic experiences. Non-food applications in cosmetics and biofuels underscore the oils' versatility. The nutritional composition, enriched with essential fatty acids, bioactive compositions, and trace elements, is explored for potential health benefits. Bioactive compounds such as phenolic compounds and terpenes contribute to antioxidant and anti-inflammatory properties, positioning mushroom oils as nutritional powerhouses. In short, this concise review synthesizes the intricate world of mushroom oils, emphasizing their nutritional significance, extraction methodologies, and potential health benefits. The comprehensive overview underscores mushroom oils as a promising area for further exploration and utilization. The characteristics of mushroom biomass oil for the use in various industries are influenced by the mushroom species, chemical composition, biochemical synthesis of mushroom, and downstream processes including extraction, purification and characterization. Therefore, further research and exploration need to be done to achieve a circular bioeconomy with the integration of SDGs, waste reduction, and economic stimulation, to fully utilize the benefits of mushroom, a valuable gift of nature.

Carotenoid characterization, fatty acid profiles, and antioxidant activities of haloarchaeal extracts

Microorganisms that can survive in saline environments, known as halotolerant or halophilic organisms, have a wide range of current and potential uses in biotechnology. In this study, it was aimed to determine the carotenoids of halophilic archaea strains isolated from the brine samples taken from different points of Salt Lake (Turkey) and determine the antioxidant activities of their carotenoids. To identify the halophilic archaea strains, they were cultivated in MAM JCM 168 medium and subjected to antibiotic susceptibility, fatty acid, two-dimensional and three-dimensional imaging by scanning electron microscopy and atomic force microscopy, biochemical and phylogenetic assays. The findings show that five different halophilic archaea strains have been identified as Halorubrum lipolyticum, Halorubrum sodomense, Haloarcula salaria, Halorubrum chaoviator, and Haloarcula japonica with 98% and above similarity ratio. The main fatty acids of all haloarchaeal strains were octadecanoic acid (C18:0) and palmitic acid (C16:0). The major carotenoid of the species was determined as all-trans bacterioruberin, and different carotenoid types such as lycopene, β-carotene, and 2-isopentenyl-3,4-dehydrorodopin were found as well as bacterioruberin isomers. The antioxidant activities of carotenoids extracted from the species were analyzed by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method and the extracts showed antioxidant activity statistically significantly higher than ascorbic acid and butylated hydroxytoluene as reference products (p < 0.05).

Induction of antioxidant activities of Arthrospira platensis and Chlorella vulgaris by modified culture conditions

Microalgae are considered a promising source for obtaining natural compounds with strong antioxidant activity. Despite the great progress made in this field, there is still need for further studies applying simple and cost-effective modifications to reveal their full potential and enhance antioxidant properties. Arthrospira platensis and Chlorella vulgaris are some of the most common cells studied for this purpose. In this study, it was aimed to develop a bioprocess for the enhancement of antioxidant properties of these two microalgae by evaluating the effect of different culture conditions. With this aim, the impacts of light intensity/reactive oxygen species and nitrogen sources/reactive oxygen species were evaluated for the A. platensis and C. vulgaris cells, respectively. Results showed that the antioxidant potential of A. platensis was found to be correlated with the phycocyanin and total phenolic content of cells, and 80 µmol photons m-2 s-1 light intensity induced antioxidant activity in a two-step cultivation mode. For C. vulgaris cells, maximum antioxidant activities of 68.10 ± 1.51% and 75.68 ± 0.66% were obtained in cultures with NH4Cl (0.016% (w/v)) for DPPH and ABTS assays, respectively. The applied oxidative stress factors exhibited different effects on the antioxidant activities of the cells because of their cellular morphologies and changing mechanisms of reactive oxygen species. These outcomes show the potential of applied modifications on cells and suggest a promising route to enhance antioxidant activities of microalgae for further research.

Skin Protection by Carotenoid Pigments

Sunlight, despite its benefits, can pose a threat to the skin, which is a natural protective barrier. Phototoxicity caused by overexposure, especially to ultraviolet radiation (UVR), results in burns, accelerates photoaging, and causes skin cancer formation. Natural substances of plant origin, i.e., polyphenols, flavonoids, and photosynthetic pigments, can protect the skin against the effects of radiation, acting not only as photoprotectors like natural filters but as antioxidant and anti-inflammatory remedies, alleviating the effects of photodamage to the skin. Plant-based formulations are gaining popularity as an attractive alternative to synthetic filters. Over the past 20 years, a large number of studies have been published to assess the photoprotective effects of natural plant products, primarily through their antioxidant, antimutagenic, and anti-immunosuppressive activities. This review selects the most important data on skin photodamage and photoprotective efficacy of selected plant carotenoid representatives from in vivo studies on animal models and humans, as well as in vitro experiments performed on fibroblast and keratinocyte cell lines. Recent research on carotenoids associated with lipid nanoparticles, nanoemulsions, liposomes, and micelles is reviewed. The focus was on collecting those nanomaterials that serve to improve the bioavailability and stability of carotenoids as natural antioxidants with photoprotective activity.

Fungi-derived natural antioxidants

In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.

Effect of Combined Chitosan and Hyperbranched Poly-L-Lysine Based Coating on Prolonging the Shelf Life of Oyster Mushroom (Pleurotus ostreatus)

To extend the shelf life of oyster mushroom (Pleurotus ostreatus), the effects of chitosan (CS) and hyperbranched poly-L-lysine (HBPL) combined treatment on quality characteristics, nutritional quality, storage characteristics, and enzyme activity of oyster mushroom during postharvest storage at 4 °C were investigated. The results showed that CS-HBPL combined treatment could significantly reduce rot degree and weight loss and significantly inhibit the browning of oyster mushroom. At the same time, the loss of reducing sugar, vitamin C, soluble protein, and total phenolic was significantly reduced. Compared with the control, CS-HBPL combined treatment could also significantly inhibit an increase in malondialdehyde (MDA) and significantly decrease the relative electrolyte leakage of oyster mushroom. In addition, the activities of catalase (CAT), superoxide dismutase (SOD), phenylalnine ammonialyase (PAL), and peroxidase (POD) were significantly improved, and the activity of polyphenol oxidase (PPO) was significantly inhibited in oyster mushroom. In conclusion, CS-HBPL combined treatment had a good protective effect on the membrane permeability damage of oyster mushroom and could effectively delay the oxidation of phenolic substances and browning of oyster mushroom. Therefore, CS-HBPL combined treatment can be used as a potential strategy to extend the storage time of oyster mushroom.

Comprehensive Response of Rhodosporidium kratochvilovae to Glucose Starvation: A Transcriptomics-Based Analysis

Microorganisms adopt diverse mechanisms to adapt to fluctuations of nutrients. Glucose is the preferred carbon and energy source for yeast. Yeast cells have developed many strategies to protect themselves from the negative impact of glucose starvation. Studies have indicated a significant increase of carotenoids in red yeast under glucose starvation. However, their regulatory mechanism is still unclear. In this study, we investigated the regulatory mechanism of carotenoid biosynthesis in Rhodosporidium kratochvilovae YM25235 under glucose starvation. More intracellular reactive oxygen species (ROS) was produced when glucose was exhausted. Enzymatic and non-enzymatic (mainly carotenoids) antioxidant systems in YM25235 were induced to protect cells from ROS-related damage. Transcriptome analysis revealed massive gene expression rearrangement in YM25235 under glucose starvation, leading to alterations in alternative carbon metabolic pathways. Some potential pathways for acetyl-CoA and then carotenoid biosynthesis, including fatty acid β-oxidation, amino acid metabolism, and pyruvate metabolism, were significantly enriched in KEGG analysis. Overexpression of the fatty acyl-CoA oxidase gene (RkACOX2), the first key rate-limiting enzyme of peroxisomal fatty acid β-oxidation, demonstrated that fatty acid β-oxidation could increase the acetyl-CoA and carotenoid concentration in YM25235. These findings contribute to a better understanding of the overall response of red yeast to glucose starvation and the regulatory mechanisms governing carotenoid biosynthesis under glucose starvation.

Antimicrobial and Antioxidant Activities of Endophytic Fungi Associated with Arrabidaea chica (Bignoniaceae)

The endophytic fungal community of the Amazonian medicinal plant Arrabidaea chica (Bignoniaceae) was evaluated based on the hypothesis that microbial communities associated with plant species in the Amazon region may produce metabolites with interesting bioactive properties. Therefore, the antimicrobial and antioxidant activities of the fungal extracts were investigated. A total of 107 endophytic fungi were grown in liquid medium and the metabolites were extracted with ethyl acetate. In the screening of fungal extracts for antimicrobial activity, the fungus identified as Botryosphaeria mamane CF2-13 was the most promising, with activity against E. coli, S. epidermidis, P. mirabilis, B. subtilis, S. marcescens, K. pneumoniae, S. enterica, A. brasiliensis, C. albicans, C. tropicalis and, especially, against S. aureus and C. parapsilosis (MIC = 0.312 mg/mL). Screening for antioxidant potential using the DPPH elimination assay showed that the Colletotrichum sp. CG1-7 endophyte extract exhibited potential activity with an EC50 of 11 µg/mL, which is equivalent to quercetin (8 µg/mL). The FRAP method confirmed the antioxidant potential of the fungal extracts. The presence of phenolic compounds and flavonoids in the active extracts was confirmed using TLC. These results indicate that two of the fungi isolated from A. chica exhibit significant antimicrobial and antioxidant potential.

Traditional uses, chemical composition, and pharmacological effects of diaphragma juglandis fructus: A review

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Uyghur medicine, diaphragma juglandis fructus (DJF) has been conventionally used in treating insomnia and nourishing the kidneys. According to traditional Chinese medicine, DJF can boosts kidney and astringent essence, strengthen the spleen and kidney, exert diuretic effect, clear heat, stop eructation, and treat vomiting.

AIM OF THE REVIEW

Research on DJF has increased gradually in recent years, but reviews of its traditional uses, chemical composition, and pharmacological activities are scarce. The purpose of this review is to analyze the traditional uses, chemical composition, and pharmacological activities of DJF and provide an overview of the findings for further research and development of DJF resources.

MATERIALS AND METHODS

Data on DJF were obtained from different databases, including Scifinder, PubMed, Web of Science, Science Direct, Springer, Wiley, ACS, CNKI, Baidu Scholar, and Google Scholar; books; and Ph.D. and MSc theses.

RESULTS

According to traditional Chinese medicine, DJF has astringent properties, inhibits bleeding and banding, strengthens the spleen and kidneys, acts as a sleeping aid by reducing anxiety, and relieves dysentery due to heat exposure. The components of DJF include flavonoids, phenolic acids, quinones, steroids, lignans, and volatile oils, which exhibit good antioxidant, antitumor, antidiabetic, antibacterial, anti-inflammatory, and sedative-hypnotic properties, and present therapeutic potential for kidney diseases.

CONCLUSIONS

Based on its traditional use, chemical composition, and pharmacological activities, DJF is a promising source of natural medicine in the development of functional foods, drugs, and cosmetics.

Genome insight and probiotic potential of three novel species of the genus Corynebacterium

Three bacterial strains, B5-R-101^T, TA-R-1^T, and BL-R-1^T, were isolated from the feces of a healthy Korean individual. Cells of these strains were Gram-stain-positive, facultatively anaerobic, oxidase-negative, catalase-positive, rod-shaped, and non-motile. They were able to grow within a temperature range of 10-42°C (optimum, 32-37°C), at a pH range of 2.0-10.0 (optimum, pH 5.5-8.0), and at NaCl concentration of 0.5-10.5% (w/v). All the three strains exhibited 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities ranging from 58 ± 1.62 to 79 ± 1.46% (% inhibition). These strains survived in lower pH (2.0) and in 0.3% bile salt concentration for 4 h. They did not show hemolytic activity and exhibited antimicrobial activity against pathogenic bacteria, such as Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, and Salmonella enterica. The genomic analysis presented no significant concerns regarding antibiotic resistance or virulence gene content, indicating these strains could be potential probiotic candidates. Phylogenetic analysis showed that they belonged to the genus Corynebacterium, with 98.5-99.0% 16S rRNA gene sequence similarities to other members of the genus. Their major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The abundant cellular fatty acids were C_16:0, C_18:1ω9c, and anteiso-C_19:0. Genomic analysis of these isolates revealed the presence of genes necessary for their survival and growth in the gut environment, such as multi-subunit ATPases, stress response genes, extracellular polymeric substance biosynthesis genes, and antibacterial genes. Furthermore, the genome of each strain possessed biosynthetic gene clusters with antioxidant and antimicrobial potentials, including terpenes, saccharides, polyketides, post-translationally modified peptides (RIPPs), and non-ribosomal peptides (NRPs). In silico DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were lower than the thresholds to distinguish novel species. Based on phenotypic, genomic, phylogenomic, and phylogenetic analysis, these potential probiotic strains represent novel species within the genus Corynebacterium, for which the names Corynebacterium intestinale sp. nov. (type strain B5-R-101^T = CGMCC 1.19408^T = KCTC 49761^T), Corynebacterium stercoris sp. nov. (type strain TA-R-1^T = CGMCC 1.60014^T = KCTC 49742^T), and Corynebacterium faecium sp. nov. (type strain BL-R-1^T = KCTC 49735^T = TBRC 17331^T) are proposed.

Microbiomic and Metabolomic Analyses Unveil the Protective Effect of Saffron in a Mouse Colitis Model

Despite the existence of effective drugs used to treat inflammatory bowel disease (IBD), many patients fail to respond or lose response over time. Further, many drugs can carry serious adverse effects, including increased risk of infections and malignancies. Saffron (Crocus sativus) has been reported to have anti-inflammatory properties. Its protective role in IBD and how the microbiome and metabolome play a role has not been explored extensively. We aimed to establish whether saffron treatment modulates the host microbiome and metabolic profile in experimental colitis. Colitis was induced in C57BL/6 mice with 3% DSS and treated with either saffron in a dose of 20 mg/kg body weight or vehicle through daily gavage. On day 10, stool pellets from mice were collected and analyzed to assess saffron's effect on fecal microbiota and metabolites through 16S rRNA sequencing and untargeted primary metabolite analysis. Saffron treatment maintained gut microbiota homeostasis by counter-selecting pro-inflammatory bacteria and maintained Firmicutes/Bacteroides ratio, which was otherwise disturbed by DSS treatment. Several metabolites (uric acid, cholesterol, 2 hydroxyglutaric acid, allantoic acid, 2 hydroxyhexanoic acid) were altered significantly with saffron treatment in DSS-treated mice, and this might play a role in mediating saffron's colitis-mitigating effects. These data demonstrate saffron's therapeutic potential, and its protective role is modulated by gut microbiota, potentially acting through changes in metabolites.

Antioxidant peptides from alternative sources reduce lipid oxidation in 5% fish oil-in-water emulsions (pH 4) and fish oil-enriched mayonnaise

Bioinformatics tools were used to predict radical scavenging and metal chelating activities of peptides derived from abundant potato, seaweed, microbial, and spinach proteins. The antioxidant activity was evaluated in 5% oil-in-water emulsions (pH4) and best-performing peptides were tested in mayonnaise and compared with EDTA. Emulsion physical stability was intact. The peptide DDDNLVLPEVYDQD showed the highest protection against oxidation in both emulsions by retarding the formation of oxidation products and depletion of tocopherols during storage, but it was less efficient than EDTA when evaluated in mayonnaise. In low-fat emulsions, formation of hydroperoxides was reduced 4-folds after 5 days compared to control. The concentration effect of the peptide was confirmed in mayonnaise at the EDTA equimolar concentration. The second-best performing peptides were NNKWVPCLEFETEHGFVYREHH in emulsion and AGDWLIGDR in mayonnaise. In general, the peptide efficacy was higher in low-fat emulsions. Results demonstrated that peptide negative net charge was important for chelating activity.

Up-Regulation of the Nrf2/HO-1 Antioxidant Pathway in Macrophages by an Extract from a New Halophilic Archaea Isolated in Odiel Saltworks

The production of reactive oxygen species (ROS) plays an important role in the progression of many inflammatory diseases. The search for antioxidants with the ability for scavenging free radicals from the body cells that reduce oxidative damage is essential to prevent and treat these pathologies. Haloarchaea are extremely halophilic microorganisms that inhabit hypersaline environments, such as saltworks or salt lakes, where they have to tolerate high salinity, and elevated ultraviolet (UV) and infrared radiations. To cope with these extreme conditions, haloarchaea have developed singular mechanisms to maintain an osmotic balance with the medium, and are endowed with unique compounds, not found in other species, with bioactive properties that have not been fully explored. This study aims to assess the potential of haloarchaea as a new source of natural antioxidant and anti-inflammatory agents. A carotenoid-producing haloarchaea was isolated from Odiel Saltworks (OS) and identified on the basis of its 16S rRNA coding gene sequence as a new strain belonging to the genus Haloarcula. The Haloarcula sp. OS acetone extract (HAE) obtained from the biomass contained bacterioruberin and mainly C18 fatty acids, and showed potent antioxidant capacity using ABTS assay. This study further demonstrates, for the first time, that pretreatment with HAE of lipopolysaccharide (LPS)-stimulated macrophages results in a reduction in ROS production, a decrease in the pro-inflammatory cytokines TNF-α and IL-6 levels, and up-regulation of the factor Nrf2 and its target gene heme oxygenase-1 (HO-1), supporting the potential of the HAE as a therapeutic agent in the treatment of oxidative stress-related inflammatory diseases.

Partitioning of Antioxidants in Edible Oil–Water Binary Systems and in Oil-in-Water Emulsions

In recent years, partitioning of antioxidants in oil–water two-phase systems has received great interest because of their potential in the downstream processing of biomolecules, their benefits in health, and because partition constant values between water and model organic solvents are closely related to important biological and pharmaceutical properties such as bioavailability, passive transport, membrane permeability, and metabolism. Partitioning is also of general interest in the oil industry. Edible oils such as olive oil contain a variety of bioactive components that, depending on their partition constants, end up in an aqueous phase when extracted from olive fruits. Frequently, waste waters are subsequently discarded, but their recovery would allow for obtaining extracts with antioxidant and/or biological activities, adding commercial value to the wastes and, at the same time, would allow for minimizing environmental risks. Thus, given the importance of partitioning antioxidants, in this manuscript, we review the background theory necessary to derive the relevant equations necessary to describe, quantitatively, the partitioning of antioxidants (and, in general, other drugs) and the common methods for determining their partition constants in both binary (PWOIL) and multiphasic systems composed with edible oils. We also include some discussion on the usefulness (or not) of extrapolating the widely employed octanol–water partition constant (PWOCT) values to predict PWOIL values as well as on the effects of acidity and temperature on their distributions. Finally, there is a brief section discussing the importance of partitioning in lipidic oil-in-water emulsions, where two partition constants, that between the oil-interfacial, POI, and that between aqueous-interfacial, PwI, regions, which are needed to describe the partitioning of antioxidants, and whose values cannot be predicted from the PWOIL or the PWOCT ones.

Zein nanoparticles for drug delivery: Preparation methods and biological applications

Zein, a vegetable protein extracted from corn (Zea mays L.), forms a gastro-resistant and mucoadhesive polymer that is cheap and easy to obtain and facilitates the encapsulation of bioactives with hydrophilic, hydrophobic, and amphiphilic properties. The methods used for synthesizing these nanoparticles include antisolvent precipitation/nanoprecipitation, pH-driven, electrospraying, and solvent emulsification-evaporation methods. Each method has its advantages in the preparation of nanocarriers, nevertheless, all of them enable the production of zein nanoparticles that are stable and resistant to environmental factors, with different biological activities required in the cosmetic, food, and pharmaceutical industries. Therefore, zein nanoparticles are promising nanocarriers that can encapsulate various bioactives with anti-inflammatory, antioxidant, antimicrobial, anticancer, and antidiabetic properties. This article reviews the principal methods for obtaining zein nanoparticles containing bioactives, the advantages and characteristics of each method, as well as the main biological applications of nanotechnology-based formulations.

A new strategy to improve Ganoderma polysaccharides production by symbiotic fungi elicitors through activating the biosynthetic pathway

Ganoderma lucidum polysaccharides (GLP) attract growing attention due to their remarkable bioactivities, but the low content in raw materials remains a bottleneck severely restricting their application. We previously found a higher polysaccharides accumulation in Ganoderma lucidum cultured in continuous cropping soil, and soil symbiotic fungi are presumed as the key among many factors. Herein, 33 symbiotic fungi were isolated from the soil, and fungal elicitors were prepared to investigate their biotic eliciting effect on GLP biosynthesis. Most elicitors were found to significantly improve GLP production, among which the NO.16 molecularly identified as Penicillium citrinum, exhibited the optimum eliciting effect with GLP yield increasing by 3.4 times. Differences in the biosynthetic pathway genes expressions and the monosaccharide components of GLP were further analyzed. The transcriptions of the main genes of GLP biosynthetic pathway were up-regulated under PCE treatments, suggesting it improves GLP production by activating transcriptions of the biosynthetic pathway genes. Moreover, PCE eliciting significantly altered the monosaccharide compositions of GLP with Gal, Man, GalA, GlcA, and Fuc increasing by 8.17 %, 5.68 %, 5.41 %, 2.66 %, and 1.51 % respectively, but Glc decreased by 23.43 %, which may result in the activity change. It can serve as a new strategy to improve GLP production.

Laying performance, egg quality, fertility, nutrient digestibility, digestive enzymes activity, gut microbiota, intestinal morphology, antioxidant capacity, mucosal immunity, and cytokine levels in meat-type Japanese quail breeders fed different phytogenic levels

A total of 180 female Japanese quail breeders were allocated to 5 treatments with 6 replicates of 6 birds and fed a diet supplemented with 0, 125, 250, 500, or 1000 mg/kg of a phytogenic feed additive (PFA) in a 9-wk experiment. Egg weight, feed efficiency, shell breaking strength and calcium content, specific gravity, Haugh unit, and percentages of fertile eggs increased with increasing PFA levels (P < 0.05). Increasing of PFA levels increased nutrient digestibility, dietary AMEn, and activities of digestive enzymes in the pancreas and intestinal digesta (P < 0.05). Supplementation of PFA reduced Escherichia coli (P < 0.05), Clostridium spp. (P < 0.05) and Salmonella spp. counts (P < 0.05), while increased Lactobacillus and Bifidobacterium spp. counts in the ileal and cecal contents (P < 0.05). Dietary PFA increased jejunal villus height and decreased ileal crypt depth (P < 0.05). Serum diamine oxidase activity and D-lactate level were decreased with increase in PFA level (P < 0.05). Increasing PFA levels increased glutathione peroxidase activity in the pancreas, small intestine, and cecal tonsil, but decreased malondialdehyde contents (P < 0.05). Birds fed PFA exhibited increased levels of secretory IgA in the intestinal mucosa (P < 0.05), and increased the percentage of CD3+ T cells, ratio of CD4+/CD8+ T cells, and cytokine concentrations in the cecal tonsils (P < 0.05). In conclusion, PFA could improve gut health and nutrient utilization and, therefore, benefit productivity, egg quality, and fertility in quails.

Arthrobacter antioxidans sp. nov., a blue pigment-producing species isolated from Mount Everest

Bacteria in the genus Arthrobacter have been found in extreme environments, e.g. glaciers, brine and mural paintings. Here, we report the discovery of a novel pink-coloured bacterium, strain QL17^T, capable of producing an extracellular water-soluble blue pigment. The bacterium was isolated from the soil of the East Rongbuk Glacier of Mt. Everest, China. 16S rRNA gene sequence analysis showed that strain QL17^T was most closely related to the species Arthrobacter bussei KR32 ^T. However, compared to A.bussei KR32^T and the next closest relatives, the new species demonstrates considerable phylogenetic distance at the whole-genome level, with an average nucleotide identity of <85 % and inferred DNA-DNA hybridization of <30 %. Polyphasic taxonomy results support our conclusion that strain QL17^T represents a novel species of the genus Arthrobacter. Strain QL17^T had the highest tolerance to hydrogen peroxide at 400 mM. Whole-genome sequencing of strain QL17^T revealed the presence of numerous cold-adaptation, antioxidation and UV resistance-associated genes, which are related to adaptation to the extreme environment of Mt. Everest. Results of this study characterized a novel psychrotolerant Arthrobacter species, for which the name Arthrobacter antioxidans sp. nov. is proposed. The type strain is QL17^T (GDMCC 1.2948^T=JCM 35246^T).

The Role of Astaxanthin as a Nutraceutical in Health and Age-Related Conditions

The current review provides an up-to-date analysis of scientific data on astaxanthin (ASX) sources and experimental studies on its health benefits as a potent antioxidant in the aging process. ASX is a liposoluble carotenoid nutrient and reddish-orange pigment, naturally synthesized by numerous microalgae, yeasts, and bacteria as secondary metabolites. Provides a reddish hue to redfish and shellfish flesh that feed on ASX-producing microorganisms. The microalga Haematococcus pluvialis is the most important source for its industrial bioproduction. Due to its strong antioxidant properties, numerous investigations reported that natural ASX is a more significant antioxidant agent than other antioxidants, such as vitamin C, vitamin E, and β-carotene. Furthermore, several data show that ASX possesses important nutraceutical applications and health benefits, especially in healthy aging processes. However, further studies are needed for a deeper understanding of the potential mechanisms through which ASX could lead to its effective role in the healthy aging process, such as supporting brain health and skin homeostasis. This review highlights the current investigations on the effective role of ASX in oxidative stress, aging mechanisms, skin physiology, and central nervous system functioning, and shows the potential clinical implications related to its consumption.

Synbiotics and Their Antioxidant Properties, Mechanisms, and Benefits on Human and Animal Health: A Narrative Review

Antioxidants are often associated with a variety of anti-aging compounds that can ensure human and animal health longevity. Foods and diet supplements from animals and plants are the common exogenous sources of antioxidants. However, microbial-based products, including probiotics and their derivatives, have been recognized for their antioxidant properties through numerous studies and clinical trials. While the number of publications on probiotic antioxidant capacities and action mechanisms is expanding, that of synbiotics combining probiotics with prebiotics is still emerging. Here, the antioxidant metabolites and properties of synbiotics, their modes of action, and their different effects on human and animal health are reviewed and discussed. Synbiotics can generate almost unlimited possibilities of antioxidant compounds, which may have superior performance compared to those of their components through additive or complementary effects, and especially by synergistic actions. Either combined with antioxidant prebiotics or not, probiotics can convert these substrates to generate antioxidant compounds with superior activities. Such synbiotic-based new routes for supplying natural antioxidants appear relevant and promising in human and animal health prevention and treatment. A better understanding of various component interactions within synbiotics is key to generating a higher quality, quantity, and bioavailability of antioxidants from these biotic sources.

A New Cryptic Lineage in Parmeliaceae (Ascomycota) with Pharmacological Properties

We used molecular data to address species delimitation in a species complex of the parmelioid genus Canoparmelia and compare the pharmacological properties of the two clades identified. We used HPLC_DAD_MS chromatography to identify and quantify the secondary substances and used a concatenated data set of three ribosomal markers to infer phylogenetic relationships. Some historical herbarium specimens were also examined. We found two groups that showed distinct pharmacological properties. The phylogenetic study supported the separation of these two groups as distinct lineages, which are here accepted as distinct species: Canoparmelia caroliniana occurring in temperate to tropical ecosystems of a variety of worldwide localities, including America, Macaronesia, south-west Europe and potentially East Africa, whereas the Kenyan populations represent the second group, for which we propose the new species C. kakamegaensis Garrido-Huéscar, Divakar & Kirika. This study highlights the importance of recognizing cryptic species using molecular data, since it can result in detecting lineages with pharmacological properties previously overlooked.

Oxidative and Microbial Stability of a Traditional Appetizer: Aubergine Salad

An eggplant-based salad, called aubergine salad (AS), is a traditional appetizer and as such, is quite popular in the Mediterranean area. It is widely produced either on a home scale or on an industrial scale and widely consumed. However, there are cases where preservatives (such as sodium benzoate and potassium sorbate) are added in order to extend the shelf life of the product. In the present study, the stability of this delicatessen against oxidation and microbial spoilage was evaluated, with or without preservatives. The physicochemical properties of the salad were evaluated, along with the tocopherol content, resistance to oxidation, and microbial count. According to the results, it is evident that the induction period of AS is 16% (in the case that preservatives were used) and 26% (in the case without preservatives) increased, compared to a control sample (plain soybean oil). This can be attributed to the increased content in tocopherols, and more specifically to α-tocopherol. Furthermore, the addition of preservatives resulted in increased storage days and a reduction of microorganisms. However, in both cases, the AS-prepared salad exhibited a self-stabilization ability after 13 days, negating the need for preservatives.

From Foods to Chemotherapeutics: The Antioxidant Potential of Dietary Phytochemicals

Food plants have been recognized for their medicinal properties for millennia, a concept supported by epidemiological studies indicating long-term health benefits for people consuming greater amounts of fruits and vegetables. As our technology and instrumentation advance, researchers have the ability to identify promising phytochemicals, and examine their potential benefits, or detriments, to human health. While results from trials investigating single chemical supplementation have sometimes produced negative health results, studies investigating the synergistic action of phytochemicals—either within our diet or as an adjuvant to radiation or chemotherapy—appear promising. Utilizing phytochemicals as synergistic agents may lower the chemotherapeutic doses needed to incur physiological results, while also using chemicals with fewer toxic effects. This review investigates a variety of plant-produced chemicals humans typically ingest, their impacts on overall health patterns, molecular mechanisms associated with their health impacts, and the potential of their synergistic use for therapeutic purposes.

Microbe-derived antioxidants attenuate cobalt chloride-induced mitochondrial function, autophagy and BNIP3-dependent mitophagy pathways in BRL3A cells

Environmental excessive cobalt (Co) exposure increases risks of public health. This study aimed to evaluate the potential mechanism of microbe-derived antioxidants (MA) blend fermented by probiotics in attenuating cobalt chloride (CoCl₂)-induced toxicology in buffalo rat liver (BRL3A) cells. Herein, results showed that some phenolic acids increased in MA compared with the samples before fermentation through UHPLC-QTOF-MS analysis. Also, the contents of essential and non-essential amino acids, their derivatives and minerals were rich in MA. The DPPH, O₂^-, OH^- and ABTS⁺ scavenging ability of MA is comparable to those of vitamin C and better than mitoquinone mesylate (mitoQ). In vitro cell experiments showed that CoCl₂ treatment increased the percentage of apoptosis cells, lactate dehydrogenase and genes involved in glycolysis, increased ATP production and decreased mitochondrial membrane potential, increased genes involved in canonical autophagy process (including initiation, autophagosomes maturation and fusion with lysosome) and BNIP3-dependent mitophagy pathways in BRL3A cells, while MA attenuated CoCl₂-induced reactive oxygen species (ROS) production, apoptosis, mitochondrial protein expression and dysfunction, and BNIP3-dependent mitophagy. Collectively, these results provide insights into the role of MA in reversing CoCl₂-induced toxicology in BRL3A cells, providing the promising constituents for decreasing Co-induced toxicology in functional foods.

Biocontrol Potential of Aspergillus Species Producing Antimicrobial Metabolites

Microbial metabolites have been recognized as an important source for the discovery of new antifungal agents because of their diverse chemical structures with novel modes of action. In the course of our screening for new antifungal agents from microbes, we found that culture filtrates of two fungal species Aspergillus candidus SFC20200425-M11 and Aspergillus montenegroi SFC20200425-M27 have the potentials to reduce the development of fungal plant diseases such as tomato late blight and wheat leaf rust. From these two Aspergillus spp., we isolated a total of seven active compounds, including two new compounds (4 and 6), and identified their chemical structures based on the NMR spectral analyses: sphaeropsidin A (1), (R)-formosusin A (2), (R)-variotin (3), candidusin (4), asperlin (5), montenegrol (6), and protulactone A (7). Based on the results of the in vitro bioassays of 11 plant pathogenic fungi and bacteria, sphaeropsidin A (1), (R)-formosusin A (2), (R)-variotin (3), and asperlin (5) exhibited a wide range of antimicrobial activity. Furthermore, when plants were treated with sphaeropsidin A (1) and (R)-formosusin A (2) at a concentration of 500 μg/ml, sphaeropsidin A (1) exhibited an efficacy disease control value of 96 and 90% compared to non-treated control against tomato late blight and wheat leaf rust, and (R)-formosusin A (2) strongly reduced the development of tomato gray mold by 82%. Asperlin (5) at a concentration of 500 μg/ml effectively controlled the development of tomato late blight and wheat leaf rust with a disease control value of 95%. Given that culture filtrates and active compounds derived from two Aspergillus spp. exhibited disease control efficacies, our results suggest that the Aspergillus-produced antifungal compounds could be useful for the development of new natural fungicides.

Desert soil fungi isolated from Saudi Arabia: cultivable fungal community and biochemical production

Desert soils harbor fungi that have survived under highly stressed conditions of high temperature and little available moisture. This study was designed to survey the communities of cultivable fungi in the desert soils of the Arabian Peninsula and to screen the fungi for the potentially valuable antioxidants (flavonoids, phenols, saponins, steroids, tannins, terpenoids, and alkaloids) and enzymes (cellulase, laccase, lipase, protease, amylase, and chitinase). Desert soil was sampled at 30 localities representing different areas of Saudi Arabia and studied for physico-chemical soil properties. Five types of soil texture (sand, loamy sand, sandy loam, silty loam, and sandy clay loam) were observed. A total of 25 saprotrophic species was identified molecularly from 68 isolates. Our survey revealed 13 culturable fungal species that have not been reported previously from Arabian desert soils and six more species not reported from Saudi Arabian desert soils. The most commonly recorded genera were Aspergillus (isolated from 20 localities) and Penicillium (6 localities). The measurements of biochemicals revealed that antioxidants were produced by 49 and enzymes by 52 isolates; only six isolates did not produce any biochemicals. The highest biochemical activity was observed for the isolates Fusarium brachygibbosum and A. phoenicis. Other active isolates were A. proliferans and P. chrysogenum. The same species, for instance, A. niger had isolates of both high and low biochemical activities. Principal component analysis gave a tentative indication of a relationship between the biochemical activity of fungi isolated from soil and soil texture variables namely the content of silt, clay and sand. However, any generalizable relation between soil properties and fungal biochemical activities cannot be suggested. Each fungal isolate is probable to produce several antioxidants and enzymes, as shown by the correlation within the compound groups. Desert soil warrants further research as a promising source of biochemicals.

Essential Oils from Annonaceae Species from Brazil: A Systematic Review of Their Phytochemistry, and Biological Activities

The present work involves a systematic review of the chemical composition and biological effects of essential oils from the Annonaceae species collected in Brazil from 2011 to 2021. Annonaceae is one of the most important botanical families in Brazil, as some species have economic value in the market as local and international fruit. In addition, the species have useful applications in several areas-for instance, as raw materials for use in cosmetics and perfumery and as medicinal plants. In folk medicine, species such as Annona glabra L. and Xylopia sericea A. St.-Hil. are used to treat diseases such as rheumatism and malaria. The species of Annonaceae are an important source of essential oils and are rich in compounds belonging to the classes of mono and sesquiterpenes; of these compounds, α-pinene, β-pinene, limonene, (E)-caryophyllene, bicyclogermacrene, caryophyllene oxide, germacrene D, spathulenol, and β-elemene are the most abundant. The antimicrobial, anti-inflammatory, antileishmania, antioxidant, antiproliferative, cytotoxic, larvicidal, trypanocidal, and antimalarial activities of essential oils from the Annonaceae species in Brazil have been described in previous research, with the most studies on this topic being related to their antiproliferative or cytotoxic activities. In some studies, it was observed that the biological activity reported for these essential oils was superior to that of drugs available on the market, as is the case of the essential oil of the species Guatteria punctata (Aubl.) R. A. Howard., which showed a trypanocidal effect that was 34 times stronger than that of the reference drug benznidazol.

Halophilic Carotenoids and Breast Cancer: From Salt Marshes to Biomedicine

Breast cancer is the leading cause of death among women worldwide. Over the years, oxidative stress has been linked to the onset and progression of cancer. In addition to the classical histological classification, breast carcinomas are classified into phenotypes according to hormone receptors (estrogen receptor-RE-/progesterone receptor-PR) and growth factor receptor (human epidermal growth factor receptor-HER2) expression. Luminal tumors (ER/PR-positive/HER2-negative) are present in older patients with a better outcome. However, patients with HER2-positive or triple-negative breast cancer (TNBC) (ER/PR/HER2-negative) subtypes still represent highly aggressive behavior, metastasis, poor prognosis, and drug resistance. Therefore, new alternative therapies have become an urgent clinical need. In recent years, anticancer agents based on natural products have been receiving huge interest. In particular, carotenoids are natural compounds present in fruits and vegetables, but algae, bacteria, and archaea also produce them. The antioxidant properties of carotenoids have been studied during the last years due to their potential in preventing and treating multiple diseases, including cancer. Although the effect of carotenoids on breast cancer during in vitro and in vivo studies is promising, clinical trials are still inconclusive. The haloarchaeal carotenoid bacterioruberin holds great promise to the future of biomedicine due to its particular structure, and antioxidant activity. However, much work remains to be performed to draw firm conclusions. This review summarizes the current knowledge on pre-clinical and clinical analysis on the use of carotenoids as chemopreventive and chemotherapeutic agents in breast cancer, highlighting the most recent results regarding the use of bacterioruberin from haloarchaea.

Recent Advances on Bioactive Ingredients of Morchella esculenta

Morchella esculenta (M. esculenta) is a delicious edible mushroom prized for its special flavor and strong health promoting abilities. Several bioactive ingredients including polysaccharides, polyphenolic compounds, proteins, and protein hydrolysates all contribute to the biological activities of M. esculenta. Different polysaccharides could be extracted and purified depending on the extraction methods and M. esculenta studied. Monosaccharide composition of M. esculenta polysaccharides (MEP) generally includes mannose, galactose, and glucose, etc. MEP possess multiple bioactivities such as antioxidant, anti-inflammation, immunoregulation, hypoglycemic activity, atherosclerosis prevention and antitumor ability. Other components like polyphenols, protein hydrolysates, and several crude extracts are also reported with strong bioactivities. In terms of potential applications of M. esculenta and its metabolites as nutritional supplements and drug supplements, this review aims to comprehensively summarize the structural characteristics, biological activities, research progress, and research trends of the active ingredients produced by M. esculenta. Among the various biological activities, the substances extracted from both natural collected and submerged fermented M. esculenta are promising for antioxidants, immunomodulation, anti-cancer and anti-inflammatory applications. However, further researches on the extraction conditions and chemical structure of bioactive compounds produced by M. esculenta still need investigations.

Integrating Antioxidant Functionality into Polymer Materials: Fundamentals, Strategies, and Applications

While antioxidants are widely known as natural components of healthy food and drinks or as additives to commercial polymer materials to prevent their degradation, recent years have seen increasing interest in enhancing the antioxidant functionality of newly developed polymer materials and coatings. This paper provides a critical overview and comparative analysis of multiple ways of integrating antioxidants within diverse polymer materials, including bulk films, electrospun fibers, and self-assembled coatings. Polyphenolic antioxidant moieties with varied molecular architecture are in the focus of this Review, because of their abundance, nontoxic nature, and potent antioxidant activity. Polymer materials with integrated polyphenolic functionality offer opportunities and challenges that span from the fundamentals to their applications. In addition to the traditional blending of antioxidants with polymer materials, developments in surface grafting and assembly via noncovalent interaction for controlling localization versus migration of antioxidant molecules are discussed. The versatile chemistry of polyphenolic antioxidants offers numerous possibilities for programmed inclusion of these molecules in polymer materials using not only van der Waals interactions or covalent tethering to polymers, but also via their hydrogen-bonding assembly with neutral molecules. An understanding and rational use of interactions of polyphenol moieties with surrounding molecules can enable precise control of concentration and retention versus delivery rate of antioxidants in polymer materials that are critical in food packaging, biomedical, and environmental applications.

Antioxidants: Classification, Natural Sources, Activity/Capacity Measurements, and Usefulness for the Synthesis of Nanoparticles

Natural extracts are the source of many antioxidant substances. They have proven useful not only as supplements preventing diseases caused by oxidative stress and food additives preventing oxidation but also as system components for the production of metallic nanoparticles by the so-called green synthesis. This is important given the drastically increased demand for nanomaterials in biomedical fields. The source of ecological technology for producing nanoparticles can be plants or microorganisms (yeast, algae, cyanobacteria, fungi, and bacteria). This review presents recently published research on the green synthesis of nanoparticles. The conditions of biosynthesis and possible mechanisms of nanoparticle formation with the participation of bacteria are presented. The potential of natural extracts for biogenic synthesis depends on the content of reducing substances. The assessment of the antioxidant activity of extracts as multicomponent mixtures is still a challenge for analytical chemistry. There is still no universal test for measuring total antioxidant capacity (TAC). There are many in vitro chemical tests that quantify the antioxidant scavenging activity of free radicals and their ability to chelate metals and that reduce free radical damage. This paper presents the classification of antioxidants and non-enzymatic methods of testing antioxidant capacity in vitro, with particular emphasis on methods based on nanoparticles. Examples of recent studies on the antioxidant activity of natural extracts obtained from different species such as plants, fungi, bacteria, algae, lichens, actinomycetes were collected, giving evaluation methods, reference antioxidants, and details on the preparation of extracts.

Isolation and characterization of marine sponge-associated Streptomyces sp. NMF6 strain producing secondary metabolite(s) possessing antimicrobial, antioxidant, anticancer, and antiviral activities

Background

Actinomycetes associated with marine sponge represent a promising source of bioactive compounds. Herein, we report the isolation, identification, and bioactivity evaluation of Streptomyces sp. NMF6 associated with the marine sponge Diacarnus ardoukobae.

Results

Results showed that the strain belonged to the genus Streptomyces, and it was designated as Streptomyces sp. NMF6 with the GenBank accession number MW015111. Ethyl acetate (EtOAc) extract of the strain NMF6 demonstrated a promising antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Vibrio damsela, and Candida albicans and a strong antioxidant activity, which were confirmed by DPPH, ferric-reducing power, and phosphomolybdenum assays; results are expressed as ascorbic acid equivalents. NMF6 extract also demonstrated cytotoxicity against breast cancer cell line (MCF-7), hepatocellular carcinoma cell line (Hep-G2), and human colon carcinoma cell line (HCT-116); the selectivity index values were < 2. The extract showed promising antiviral activity against HSV-1, CoxB4, and hepatitis A viruses at concentrations that were nontoxic to the host cells, with the selectivity index values being 13.25, 9.42, and 8.25, respectively. GC-MS analysis of the extract showed the presence of 20 compounds, with bis(2-ethylhexyl) phthalate being the major component (48%).

Conclusions

Our study indicates that the marine sponge–associated Streptomyces sp. NMF6 strain is a potential source of bioactive compounds that could be developed into therapeutic agents.

In Vitro and In Vivo Antifungal Activity of Sorbicillinoids Produced by Trichoderma longibrachiatum

In the search for antifungal agents from marine resources, we recently found that the culture filtrate of Trichoderma longibrachiatum SFC100166 effectively suppressed the development of tomato gray mold, rice blast, and tomato late blight. The culture filtrate was then successively extracted with ethyl acetate and n-butanol to identify the fungicidal metabolites. Consequently, a new compound, spirosorbicillinol D (1), and a new natural compound, 2',3'-dihydro-epoxysorbicillinol (2), together with 11 known compounds (3-13), were obtained from the solvent extracts. The chemical structures were determined by spectroscopic analyses and comparison with literature values. The results of the in vitro antifungal assay showed that of the tested fungal pathogens, Phytophthora infestans was the fungus most sensitive to the isolated compounds, with MIC values ranging from 6.3 to 400 µg/mL, except for trichotetronine (9) and trichodimerol (10). When tomato plants were treated with the representative compounds (4, 6, 7, and 11), bisvertinolone (6) strongly reduced the development of tomato late blight disease compared to the untreated control. Taken together, our results revealed that the culture filtrate of T. longibrachiatum SFC100166 and its metabolites could be useful sources for the development of new natural agents to control late blight caused by P. infestans.

Lichens as a repository of bioactive compounds: an open window for green therapy against diverse cancers

Lichens, algae and fungi-based symbiotic associations, are sources of many important secondary metabolites, such as antibiotics, anti-inflammatory, antioxidants, and anticancer agents. Wide range of experiments based on in vivo and in vitro studies revealed that lichens are a rich treasure of anti-cancer compounds. Lichen extracts and isolated lichen compounds can interact with all biological entities currently identified to be responsible for tumor development. The critical ways to control the cancer development include induction of cell cycle arrests, blocking communication of growth factors, activation of anti-tumor immunity, inhibition of tumor-friendly inflammation, inhibition of tumor metastasis, and suppressing chromosome dysfunction. Also, lichen-based compounds induce the killing of cells by the process of apoptosis, autophagy, and necrosis, that inturn positively modulates metabolic networks of cells against uncontrolled cell division. Many lichen-based compounds have proven to possess potential anti-cancer activity against a wide range of cancer cells, either alone or in conjunction with other anti-cancer compounds. This review primarily emphasizes on an updated account of the repository of secondary metabolites reported in lichens. Besides, we discuss the anti-cancer potential and possible mechanism of the most frequently reported secondary metabolites derived from lichens.

Optimising the DPPH Assay for Cell-Free Marine Microorganism Supernatants

Antioxidants prevent ageing and are usually quantified and screened using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. However, this assay cannot be used for salt-containing samples, such as the cell-free supernatants of marine microorganisms that are aggregated under these conditions. Herein, the DPPH solvent (methanol or ethanol) and its water content were optimized to enable the analysis of salt-containing samples, aggregation was observed for alcohol contents of >70%. The water content of methanol influenced the activities of standard antioxidants but did not significantly affect that of the samples. Based on solution stability considerations, 70% aqueous methanol was chosen as the optimal DPPH solvent. The developed method was successfully applied to the cell-free supernatants of marine bacteria (Pseudoalteromonas rubra and Pseudoalteromonas xiamenensis), revealing their high antioxidant activities. Furthermore, it was concluded that this method would be useful for the screening of marine microorganism-derived antioxidants, which also has numerous potential applications, such as salt-fermented foods.

Actinomycete strain type determines the monodispersity and antibacterial properties of biogenically synthesized silver nanoparticles

BACKGROUND

Bio-nanotechnology is considered as one of the low-cost approaches that have been utilized in production of nanomaterials. The current research aimed at investigating the influence of different types of Actinomycete strains on the final properties of silver nanoparticles (AgNPs) such as size, shape, polydispersity, and antibacterial properties. For this purpose, the following techniques were employed UV spectrophotometer, SDS-PAGE electrophoresis, TEM, FTIR, antibacterial agar diffusion test, and Zetasizer.

RESULTS

It was found that among 34 Streptomyces isolates collected from the soil, Streptomyces spiralis and Streptomyces rochei were able to reduce silver nitrate into sliver nanoparticles. The diversity and molecular weights of extracellular proteins secreted by these stains were different as proved by SDS-PAGE technique. This consequently resulted in differences in polydispersity of AgNPs which indicate that the sizes of AgNPs were highly dependent on the amount, molecular sizes, and diversity of extracellular matrix proteins of the microorganism.

CONCLUSION

This article might give an insight about the importance of molecular sizes of biomacromolecules such as proteins on the physical properties of biogenic synthesized nanoparticles.

A Novel 4H-Chromen-4-One Derivative from Marine Streptomyces ovatisporus S4702T as Potential Antibacterial and Anti-Cancer Agent

BACKGROUND

Marine actinomycetes are among indispensable sources of natural bioactive compounds with unique antimicrobial and anti-cancer activities.

OBJECTIVE

Herein, it was aimed to elucidate bioactive potential of a marine-derived Streptomyces ovatisporus S4702T, isolated previously.

METHODS

Streptomyces ovatisporus S4702T was cultured in N-Z Amine broth and extraction was carried out using different organic solvents. Bioassay guided purification was followed by chemical characterization using NMR and LC-MS/MS. The compound was then evaluated for its antibacterial, antioxidant and cytotoxic activities.

RESULTS

Etyl acetate extracts gave the highest antibacterial activity and chemical characterization of this extract indicated the formula as C15H29O5N3 and the corresponding possible molecular structure as 4H-chromen-4-one derivative. It was found highly potent against Bacillus subtilis ATCC 6633 (MIC: 0.25 µg ml-1) and Micrococcus luteus ATCC 9341 (MBC: 0.5 µg ml-1). It has no remarkable antioxidant activity, but higher EC50 value and less cytotoxicity against normal cells. The EC50 values of this chromen derivative were found as 9.68 µg ml-1 for human colon carcinoma, 9.93 µg ml-1 for human prostate adenocarcinoma and 25.5 µg ml-1 for human embryonic kidney cells.

CONCLUSION

Overall, the presented 4H-chromen-4-one derivative is a remarkable bioactive compound with potent antibacterial and cytotoxic activity. With its high bioactive potential, it is proposed as a good candidate in medicine.

Coating shiitake mushrooms (Lentinus edodes) with a polysaccharide from Oudemansiella radicata improves product quality and flavor during postharvest storage

In this work, we investigated whether coating fresh shiitake mushrooms with a polysaccharide isolated from Oudemansiella radicata (ORWP) would impact key quality characteristics after 18 d of storage at 4 °C. We found that ORWP-coated mushrooms had significant improvements in many qualities during storage, including reduced weight loss, improved firmness, reduced browning, decreased malondialdehyde content, and an improved physical microstructure. Further, ORWP-coated mushrooms had higher contents of nutritional and cell wall compounds compared to control samples. ORWP-coated mushrooms had reduced activities of the following enzymes: protease, polyphenol oxidase, peroxidase, phenylalanine ammonia lyase, cellulase, and chitinase, relative to control samples. However, mushrooms coated with ORWP had higher concentrations of superoxide dismutase and catalase, as well as higher contents of certain key monosodium glutamate-resembling amino acids, umami 5'-nucleotides and 1-octen-3-ol. These findings suggest that ORWP coatings have potential value as a method to improve the postharvest quality of shiitake mushrooms.