Mitigating drought stress in wheat plants (Triticum Aestivum L.) through grain priming in aqueous extract of spirulina platensis.

BACKGROUND: The study focuses on the global challenge of drought stress, which significantly impedes wheat production, a cornerstone of global food security. Drought stress disrupts cellular and physiological processes in wheat, leading to substantial yield losses, especially in arid and semi-arid regions. The research investigates the use of Spirulina platensis aqueous extract (SPAE) as a biostimulant to enhance the drought resistance of two Egyptian wheat cultivars, Sakha 95 (drought-tolerant) and Shandawel 1 (drought-sensitive). Each cultivar's grains were divided into four treatments: Cont, DS, SPAE-Cont, and SPAE + DS. Cont and DS grains were presoaked in distilled water for 18 h while SPAE-Cont and SPAE + DS were presoaked in 10% SPAE, and then all treatments were cultivated for 96 days in a semi-field experiment. During the heading stage (45 days: 66 days), two drought treatments, DS and SPAE + DS, were not irrigated. In contrast, the Cont and SPAE-Cont treatments were irrigated during the entire experiment period. At the end of the heading stage, agronomy, pigment fractions, gas exchange, and carbohydrate content parameters of the flag leaf were assessed. Also, at the harvest stage, yield attributes and biochemical aspects of yielded grains (total carbohydrates and proteins) were evaluated. RESULTS: The study demonstrated that SPAE treatments significantly enhanced the growth vigor, photosynthetic rate, and yield components of both wheat cultivars under standard and drought conditions. Specifically, SPAE treatments increased photosynthetic rate by up to 53.4%, number of spikes by 76.5%, and economic yield by 190% for the control and 153% for the drought-stressed cultivars pre-soaked in SPAE. Leaf agronomy, pigment fractions, gas exchange parameters, and carbohydrate content were positively influenced by SPAE treatments, suggesting their effectiveness in mitigating drought adverse effects, and improving wheat crop performance. CONCLUSION: The application of S. platensis aqueous extract appears to ameliorate the adverse effects of drought stress on wheat, enhancing the growth vigor, metabolism, and productivity of the cultivars studied. This indicates the potential of SPAE as an eco-friendly biostimulant for improving crop resilience, nutrition, and yield under various environmental challenges, thus contributing to global food security.

Beneficial Effects of Spirulina Supplementation in the Management of Cardiovascular Diseases.

In recent decades, as a result of rising mortality rates due to cardiovascular diseases (CVDs), there has been a growing urgency to find alternative approaches to conventional pharmaceutical treatment to prevent the onset of chronic diseases. Arthrospira platensis, commonly known as Spirulina, is a blue-green cyanobacterium, classified as a "superfood", used worldwide as a nutraceutical food supplement due to its remarkable nutritional value, lack of toxicity, and therapeutic effects. Several scientific studies have evaluated the cardioprotective role of Spirulina. This article presents a comprehensive review of the therapeutic benefits of Spirulina in improving cardio- and cerebrovascular health. It focuses on the latest experimental and clinical findings to evaluate its antihypertensive, antidiabetic, and antihyperlipidemic properties. The objective is to highlight its potential in preventing and managing risk factors associated with cardiovascular disease (CVD).

Green fabrication of ZnO nanoparticles via spirulina platensis and its efficiency against biofilm forming pathogens.

Excessive consumption of antibiotics is considered one of the top public health threats, this necessitates the development of new compounds that can hamper the spread of infections. A facile green technology for the biosynthesis of Zinc oxide nanoparticles (ZnO NPs) using the methanol extract of Spirulina platensis as a reducing and stabilizing agent has been developed. A bunch of spectroscopic and microscopic investigations confirmed the biogenic generation of nano-scaled ZnO with a mean size of 19.103 ± 5.66 nm. The prepared ZnO NPs were scrutinized for their antibacterial and antibiofilm potentiality, the inhibition zone diameters ranged from 12.57 ± 0.006 mm to 17.33 ± 0.006 mm (at 20 µg/mL) for a variety of Gram-positive and Gram-negative pathogens, also significant eradication of the biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae by 96.7% and 94.8% respectively was detected. The free radical scavenging test showed a promising antioxidant capacity of the biogenic ZnO NPs (IC50=78.35 µg/mL). Furthermore, the anti-inflammatory role detected using the HRBCs-MSM technique revealed an efficient stabilization of red blood cells in a concentration-dependent manner. In addition, the biogenic ZnO NPs have significant anticoagulant and antitumor activities as well as minimal cytotoxicity against Vero cells. Thus, this study offered green ZnO NPs that can act as a secure substitute for synthetic antimicrobials and could be applied in numerous biomedical applications.

A rapid one-step affinity purification of C-phycocyanin from Spirulina platensis.

The high-purity phycocyanin has a high commercial value. Most current purification methods of C-phycocyanin involve multiple steps, which are complicated and time-consuming. To solve the problem, this research was studied, and an efficient affinity chromatography purification for C-phycocyanin from Spirulina platensis was developed. Through molecular docking simulation, virtual screening of ligands was performed, and ursolic acid was identified as the specific affinity ligand, which coupled to Affi-Gel 102 gel via 1-ethyl (3-dimethylaminopropyl)-3-carbodiimide, hydrochloride as coupling agent. With this customized and synthesized resin, a high-efficiency one-step purification procedure for C-phycocyanin was developed and optimized, the purity was determined to be 4.53, and the yield was 69 %. This one-step purification protocol provides a new approach for purifying other phycobilin proteins.

Algae-Based Supplements Claiming Weight Loss Properties: Authenticity Control and Scientific-Based Evidence on Their Effectiveness.

The worldwide prevalence of obesity impacts more than 600 million adults. Successfully managing weight is effective in reducing the risk of chronic diseases, but sustaining long-term weight loss remains a challenge. Although there are supplements based on algae that claim to aid in weight loss, there is a notable scarcity of scientific evidence supporting their effectiveness, and their regular consumption safety remains inadequately addressed. In this work, commercially available Arthrospira (Spirulina) platensis Gomont and/or Fucus vesiculosus L. supplements showed moderate capacity to inhibit the activity of carbohydrate-metabolizing enzymes, and to scavenge biologically relevant reactive species. IC25 values varying between 4.54 ± 0.81 and 66.73 ± 5.91 µg of dry extract/mL and between 53.74 ± 8.42 and 1737.96 ± 98.26 µg of dry extract/mL were obtained for α-glucosidase and aldose reductase, respectively. A weaker effect towards α-amylase activity was observed, with a maximum activity of the extracts not going beyond 33%, at the highest concentrations tested. Spirulina extracts showed generally better effects than those from F. vesiculosus. Similar results were observed concerning the antiradical capacity. In a general way, the extracts were able to intercept the in vitro-generated reactive species nitric oxide (•NO) and superoxide anion (O2•-) radicals, with better results for O2•-scavenging with the spirulina samples (IC25 values of 67.16 and 122.84 µg of dry extract/mL). Chemically, similar pigment profiles were observed between spirulina supplements and the authenticated counterpart. However, fucoxanthin, the chemotaxonomic marker of brown seaweeds, was not found in F. vesiculosus samples, pointing to the occurrence of a degradation phenomenon before, during, or after raw material processing. Our findings can contribute to providing data to allow regulatory entities (e.g., EFSA and FDA) to better rule these products in a way that can benefit society.

Exploring effective light spectral conversion techniques for enhanced production of Spirulina-derived blue pigment protein, c-phycocyanin.

Spirulina is a promising feedstock for c-phycocyanin, a blue pigment-protein, commercially incorporated in many food products for its desirable bright blue attributes, exceptional bioavailability, and inherent therapeutic properties. Remarkably, enhancing c-phycocyanin synthesis in Spirulina would facilitate economic viability and sustainability at large-scale production, as the forecasted market value is $ 409.8 million by 2030. Notably, the lighting source plays a key role in enhancing c-phycocyanin in Spirulina, and thus, strategies to filter/concentrate the photons of respective wavelengths, influencing light spectra, are beneficial. Enveloping open raceway ponds and greenhouses by luminescent solar concentrators and light filtering sheets enables solar spectral conversion of the sunlight at desirable wavelengths, emerges as a promising strategy to enhance synthesis of c-phycocyanin in Spirulina. Nevertheless, the conduction of techno-economic assessments and evaluation of scalability at large-scale cultivation of Spirulina are essential for the real-time implementation of lighting strategies.

Investigation on the enhancement of crack restoration properties in cement incorporated with Arthrospira platensis cultured in modified medium.

This study investigated the potential use of microalgae as partial cement replacement to heal cracks in cement mortar. Microbially induced calcite (CaCO3) precipitation (MICP) from Arthrospira platensis (A. platensis) (UMACC162) was utilised for crack-healing applications. Microalgae was cultivated in Kosaric Media (KM) together with filtered cement water (FCW), and used as a cement replacement material. The microalgal species was further evaluated for its capacity and adaptability towards large-scale culturing. The results showed that A. platensis could adapt and survive in cement water solution and cement mortar, suggesting the potential for self-healing in cement mortar. Further, the cultured species grown in both conditions (KM and KM & FCW) were harvested and incorporated into the cement mortar as a partial cement replacement material at different levels of 5%, 10%, 20%, and 30% of cement weight. The cement mortars partially replaced with microalgae were cured in water for 28 days. Pre-cracks were induced in the cured mortar with the 75% of their ultimate load. It took just 14 days for the microalgae-incorporated mortar to heal the cracks. The specimens with microalgae cultured in FCW showed a better performance and recovered 59% of their strength, with a maximum healed crack width of 0.7 mm. In terms of water tightness and porosity, they are comparable to the control mortar. The compressive strength measurements indicated the formation of calcite aggregate (crystal) that sealed the surface cracks, which was confirmed by a microstructural analysis. The results also demonstrate that the incorporation of microalgae into cement produced a self-healing effect, providing a new direction for crack healing. Additionally, the investigation indicated that replacing cement with microalgae reduced CO2 emissions by as much as 30%, with a substitution of 30% of microalgae. Exploring microalgae as a cement replacement could reduce carbon emissions and improve the state of the environment.

Prefeeding of Clarias gariepinus with Spirulina platensis counteracts petroleum hydrocarbons-induced hepato- and nephrotoxicity.

Petroleum aromatic hydrocarbons are considered one of the most dangerous aquatic pollutants due to their widespread across water bodies, persistence, and extension to the food chain. To our knowledge, there hasn't been any research investigating the hepatorenoprotective effects of Spirulina platensis (SP) against toxicity induced by these environmental toxicants in fish. Thus, we decided to explore its potential safeguarding against benzene and toluene exposure in adult Clarias gariepinus. To achieve this objective, fish were divided into five groups (60 per group; 20 per replicate). The first group served as a control. The second and third groups were intoxicated with benzene and toluene at doses of 0.762 and 26.614 ng/L, respectively for 15 days. The fourth and fifth groups (SP + benzene and SP + toluene, respectively) were challenged with benzene and toluene as previously mentioned following dietary inclusion of SP at a dose of 5 g/kg diet for 30 days. The marked increase in liver metabolizing enzymes, glucose, total protein, albumin, globulin, albumin/globulin ratio, and creatinine confirmed the hepato- and nephrotoxic impacts of benzene and toluene. These outcomes were coupled with cytopathological affections and excessive collagen deposition. The incorporation of SP in ration formulation, on the contrary, restored the previously mentioned toxicological profile due to its antioxidant and cytoprotective attributes. Regardless of SP intervention, the renal tissues still displayed histo-architectural lesions, because of insufficient dose and timeframe. Additional research will be required to identify the ideal SP remediation regimen.

Improvement of growth and biochemical constituents of Rosmarinus officinalis by fermented Spirulina maxima biofertilizer.

Delayed growth period and nature of woody stems are challenges for the urgent economic needs of rosemary plant culturing in the winter season. Different concentrations of biofertilizer initiated from Spirulina maxima, marine Lactobacillus plantarum, molasses and industrial organic waste (IOW) were subjected to freshly cut cuttings of the Rosmarinus officinalis L. (rosemary) plant to study the impact of this biofertilizer on the growth performance of the plant. The present work explored the potential of this biofertilizer in concentrations of 0.5%-1% and achieved a significant impact on the growth parameters and biochemical constituents of R. officinalis, a 27-day-old plant. The development of adventitious roots was earlier within one week, particularly at 0.5% and 1%. It can be concluded that the application of this biofertilizer at the lower concentrations enhanced the production of bioactive substances such as phytohormones (auxin, cytokinin, and gibberellins), carbohydrates, and vitamins; moreover, through controlling a range of physiological and biochemical processes, it can promote the intake of nutrients. Thus, this biofertilizer (Spirulina maxima, marine Lactobacillus plantarum, molasses and IOW) at a concentration of 1% is the recommended dose for application to agriculture sustainability.

Effects of Spirulina supplementation in patients with ulcerative colitis: a double-blind, placebo-controlled randomized trial.

AIM: We conducted a randomized placebo-controlled trial to assess the efficacy of Spirulina (SP) supplementation on disease activity, health-related quality of life, antioxidant status, and serum pentraxin 3 (PTX-3) levels in patients with ulcerative colitis (UC). METHODS: Eighty patients with UC were randomly assigned to consume either 1 g/day (two 500 mg capsules/day) of SP (n = 40) or control (n = 40) for 8 weeks. Dietary intakes, physical activity, disease activity, health-related quality of life, antioxidant status, erythrocyte sedimentation rate (ESR), and serum PTX-3 levels were assessed and compared between groups at baseline and post-intervention. RESULTS: Seventy-three patients (91.3%) completed the trial. We observed increases in serum total antioxidant capacity levels in the SP supplementation group compared to the control group after 8 weeks of intervention (p ≤ 0.001). A within-group comparison indicated a trend towards a higher health-related quality of life score after 8 weeks of taking two different supplements, SP (p < 0.001) and PL (p = 0.012), respectively. However, there were no significant changes in participant's disease activity score in response to SP administration (p > 0.05). Similarly, changes in ESR and PTX-3 levels were comparable between groups post-intervention (p > 0.05). CONCLUSIONS: SP improved antioxidant capacity status and health-related quality of life in patients with UC. Our findings suggest that SP supplementation may be effective as an adjuvant treatment for managing patients with UC. Larger trials with longer interventions periods are required to confirm our findings.

Saline extraction assisted by ultrasound: a method to obtain purified phycocyanin.

The influence of ultrasound intensity and saline solution concentration (NH4Cl and CaCl2) on phycocyanin extraction from Arthrospira platensis was evaluated. The intensity had a significant effect on phycocyanin content and purity, while the saline solution concentration only had an effect on purity. The optimum extraction condition was obtained at 41% of intensity and 8.5 g.L-1 of CaCl2 solution. In this condition, ultrasound promoted cell disruption efficiently, increasing the extraction yield. The combination of ultrasound with CaCl2 solution reduced the co-extraction of chlorophylls and other proteins, providing more purified extracts. The freezing and thawing method was compared to the best condition obtained, and it showed no significant difference for phycocyanin content but better results for purity. Overall, ultrasound treatment may be considered a promising technology to obtain phycocyanin by the food industry without additional purification techniques due to the reduced extraction time, less use of energy, and easy scale-up.

Concurrent enhancement of biomass production and phycocyanin content in salt-stressed Arthrospira platensis: A glycine betaine- supplementation approach.

In industrial-scale cultivation of microalgae, salinity stress often stimulates high-value metabolites production but decreases biomass yield. In this research, we present an extraordinary response of Arthrospira platensis to salinity stress. Specifically, we observed a significant increase in both biomass production (2.58 g L-1) and phycocyanin (PC) content (22.31%), which were enhanced by 1.26-fold and 2.62-fold, respectively, compared to the control, upon exposure to exogenous glycine betaine (GB). The biochemical analysis reveals a significant enhancement in carbonic anhydrase activity and chlorophyll a level, concurrent with reductions in carbohydrate content and reactive oxygen species (ROS) levels. Further, transcriptomic profiling indicates a downregulation of genes associated with the tricarboxylic acid (TCA) cycle and an upregulation of genes linked to nitrogen assimilation, hinting at a rebalanced carbon/nitrogen metabolism favoring PC accumulation. This work thus presents a promising strategy for simultaneous enhancement of biomass production and PC content in A. platensis and expands our understanding of PC biosynthesis and salinity stress responses in A. platensis.

A multiplex metabolomic approach for quality control of Spirulina supplement and its allied microalgae (Amphora & Chlorella) assisted by chemometrics and molecular networking.

Microalgae species are of economic importance regarded as "green gold" being rich in bioactive compounds. Spirulina and Chlorella are the most popular microalgal species and are marketed as healthy food supplements. At the same time, Amphora holds potential as a source of healthy lipids and essential fatty acids. Yet, there are considerable variations in their reported chemical composition, and less is known about their compositional differences. A multiplexed metabolomic approach was adopted for the quality control (QC) of Spirulina supplements and to compare its constitutive metabolome to Chlorella and Amphora. The adopted protocol comprised gas chromatography-mass spectrometry (GC-MS), ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS), and ultraviolet-visible spectrophotometry (UV/Vis) for mapping their primary and secondary metabolome. Interestingly, UPLC-HRMS/MS analysis delineated the abundance of fatty acids in Amphora versus glycolipids enrichment in Spirulina, and porphyrins were the main pigments identified in Spirulina, with scarce occurrence in Chlorella. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) analysis of GC-MS data set revealed palmitic acid, 3-mannobiose, and glyceryl-glycoside as being most enriched in Spirulina, versus sucrose and leucine in Chlorella and Amphora, respectively. Despite being of low discriminatory potential, UV/Vis OPLS-DA modeling showed that Spirulina was distinguished with the UV absorbances of carotenoids and chlorophyll pigments, as indicated by its OPLS-DA derived S-plot. Our study provides a QC approach for the analysis of the microalgal species and poses alternative spectral and compositional markers for their discrimination.

Anti-Glycation Properties of Zinc-Enriched Arthrospira platensis (Spirulina) Contribute to Prevention of Metaflammation in a Diet-Induced Obese Mouse Model.

Advanced glycation end products (AGEs) exert a key pathogenic role in the development of obesity and insulin resistance. Thanks to its abundance in bioactive compounds, the microalga Arthrospira platensis (spirulina, SP) is proposed as a nutritional supplement. Here, we investigated the potential anti-glycating properties of SP enriched with zinc (Zn-SP) and the following impact on diet-induced metabolic derangements. Thirty male C57Bl6 mice were fed a standard diet (SD) or a high-fat high-sugar diet (HFHS) for 12 weeks, and a subgroup of HFHS mice received 350 mg/kg Zn-SP three times a week. A HFHS diet induced obesity and glucose intolerance and increased plasma levels of pro-inflammatory cytokines and transaminases. Zn-SP administration restored glucose homeostasis and reduced hepatic dysfunction and systemic inflammation. In the liver of HFHS mice, a robust accumulation of AGEs was detected, paralleled by increased expression of the main AGE receptor (RAGE) and depletion of glyoxalase-1, whereas Zn-SP administration efficiently prevented these alterations reducing local pro-inflammatory responses. 16S rRNA gene profiling of feces and ileum content revealed altered bacterial community structure in HFHS mice compared to both SD and HFHS + Zn-SP groups. Overall, our study demonstrates relevant anti-glycation properties of Zn-SP which contribute to preventing AGE production and/or stimulate AGE detoxification, leading to the improvement of diet-related dysbiosis and metabolic derangements.

Spirulina Platensis Attenuates Rebound Dyspeptic Symptoms After Proton Pump Inhibitors' Discontinuation: Phase 2 Placebo-controlled Trial.

Context: Rebound acid hypersecretion after cessation of proton pump inhibitors (PPIs) can provoke dyspeptic symptoms. The search for alternatives to minimize the dyspeptic rebound symptoms after PPI discontinuation is warranted. Spirulina platensis, a dietary supplement made from blue-green algae, might be an alternative. Objective: The study intended to assess whether Spirulina platensis, through its anti-inflammatory and analgesic properties, can minimize rebound symptoms after PPI withdrawal. Design: The research team performed a randomized, phase 2, double-blinded, placebo-controlled clinical trial. Setting: The study took place at São Vicente de Paulo Hospital (trial registry number NCT04988347) in Passo Fundo, Brazil. Participants: Participants were 45 Brazilian patients in the clinical practice of two of the research team's member between November 2010 and February 2012, who were using PPIs regularly. Interventions: Participants underwent clinical and endoscopic evaluations after a 28-day run-in phase of 40 mg/day of pantoprazole. In the absence of a large hiatal hernia, peptic ulcer, or severe reflux esophagitis, participants stopped using PPIs, and the research team randomly assigned them to receive either 1.6g/day of spirulina or of a placebo for two months, followed by clinical and endoscopic reevaluations. Outcome measures: Using an intention-to-treat analysis, the primary outcomes postintervention were dyspepsia and typical reflux symptoms, either the appearance or maintenance of symptoms of >50% from baseline. Results: The median time of continuous PPI use was 32 months. The research team excluded two participants due to large hiatal hernias. Among the remaining 43 participants, 18 received spirulina (42%), and 25 used a placebo (58%). Two months later, 12 participants who had received spirulina (67%) and 18 who had received the placebo (72%) completed the study (P = .968). Rebound dyspepsia occurred in 10 out of 18 patients treated with spirulina (55.56%) and in 22 out of 25 patients treated with placebo (88%), with relative risk=0.63, CI95% (0.41-0.98), and P = .039. Reflux symptoms postintervention occurred in 72% and 76%, with the relative risk=0.95, CI95% (0.66-1.36), and P > .05, respectively. No significant side effects occurred in either group. The findings from endoscopy and gastric histology didn't differ between groups. Conclusions: A two-month course of Spirulina platensis was able to attenuate rebound dyspepsia but not reflux symptoms after PPI discontinuation. Considering its good safety profile, spirulina might be useful to relieve dyspeptic symptoms after PPI discontinuation.

Doxorubicin-Loaded Microalgal Delivery System for Combined Chemotherapy and Enhanced Photodynamic Therapy of Osteosarcoma.

Osteosarcoma (OS) is considered the most frequent type of primary malignant bone tumor. Currently, radiotherapy, photodynamic (PDT), and other therapies for osteosarcoma are limited by tumor hypoxia and single efficacy and serve side-effects. Herein, we reported a microalgal drug delivery system (SpiD), doxorubicin (DOX)-loaded Spirulina platensis (Spi) for OS therapy. The specific surface of Spirulina platensis allowed for effective loading of DOX via surface channels and electrostatic interactions. Under 650 nm laser irradiation, SpiD enabled high oxygen production by photosynthesis and enhanced reactive oxygen species (ROS) generation via chlorophyll-assisted photosensitization, synergistically killing tumor cells with the released DOX. Combined chemotherapy and enhanced PDT mediated by SpiD exerted synergic antitumor effects and resulted in potent therapeutic efficacy in orthotopic osteosarcoma mice. Furthermore, SpiD could reduce the side-effects of chemotherapy, showing excellent blood and tissue safety. Taken together, this microalgal drug delivery system provided a natural, efficient, safe, and inexpensive strategy for OS treatment.

Identification and molecular docking of tyrosinase inhibitory peptides from allophycocyanin in Spirulina platensis.

BACKGROUND: Tyrosinase, a copper-containing metalloenzyme with catalytic activity, is widely found in mammals. It is the key rate-limiting enzyme that catalyzes melanin synthesis. For humans, tyrosinase is beneficial to the darkening of eyes and hair. However, excessive deposition of melanin in the skin can lead to dull skin color and lead to pigmentation. Therefore, many skin-whitening compounds have been developed to decrease tyrosinase activity. This study aimed to identify a new tyrosinase inhibitory peptide through enzymatic hydrolysis, in vitro activity verification, molecular docking, and molecular dynamics (MD) simulation. RESULTS: A tripeptide Asp-Glu-Arg (DER) was identified, with a '-CDOCKER_Energy' value of 121.26 Kcal mol-1 . DER has effective tyrosinase inhibitory activity. Research shows that its half maximal inhibitory concentration value is 1.04 ± 0.01 mmol L-1 . In addition, DER binds to tyrosinase residues His85, His244, His259, and Asn260, which are key residues that drive the interaction between the peptide and tyrosinase. Finally, through MD simulation, the conformational changes and structural stability of the complexes were further explored to verify and supplement the results of molecular docking. CONCLUSION: This experiment shows that DER can effectively inhibit tyrosinase activity. His244, His259, His260, and Asn260 are the critical residues that drive the interaction between the peptide and tyrosinase, and hydrogen bonding is an important force. DER from Spirulina has the potential to develop functional products with tyrosinase inhibition. © 2024 Society of Chemical Industry.

Impact of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis as bio-stimulants on common bean plant growth, yield and antioxidant capacity.

The use of bio-stimulants in agriculture has emerged as a promising strategy to improve crop growth and yield. One type of bio-stimulant that has gained attention is microalgae extracts, which are known for their high metabolic activity, bioactive compounds, and ability to enhance plant growth and development. To investigate their effectiveness, a pot experiment was conducted at the Experimental Farm of Helwan University in Egypt during the 2022 season. The experiment aimed to evaluate the efficacy of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis (Spirulina platensis) extracts as bio-stimulants, applied through foliar spray at concentrations ranging from 0.25 to 2.0%, on common bean plants. Analysis of algal extract showed that . N. salina had the highest content of promotive growth hormones gibberellins (GA3) (74.85 ± 2.7mg100 g-1 d.wt). and auxins (IAA) (34.57 ± 2.7µg 100 g-1 d.wt.) compared to Chlorella and Arthrospira..The results revealed that the application of C. vulgaris, N. salina, and A. platensis extracts at concentrations up to 1.0% significantly improved various growth parameters, such as root, and shoot length, number of leaves and flowers per plant, leaf area, and total fresh and dry weight per plant. These extracts also positively affected yield attributes, including the number and fresh weight of pods per plant, seed index, seed yield per plant, and per feddan [a unit of land area]. Furthermore, the application of these extracts increased the chlorophyll content index with the maximum values of CCI (17.95. and 17.81%) was obtained at 0.50% N. salina, followed by 0.50% C.vulgaris. In addition to increase in the capacity of both non-enzymatic antioxidants [such as total antioxidant capacity, phenolics, and flavonoids] and enzymatic antioxidants [including catalase and ascorbic oxidase]. The most promising results were observed with the application of N. salina, and C. vulgaris extracts at a concentration of 0.5%. Additionally, the extracts significantly reduced the content of oxidative stress markers, such as malondialdehyde, percentage of electrolyte leakage, and hydrogen peroxide, in common bean plants compared to the control group. Contrarily, the measured parameters were reduced, while the levels of oxidative stress markers and some antioxidants including peroxidase, ascorbic peroxidase, superoxide dismutase, glutathione peroxidase, and glutathione transferase were increased by three algal extracts at a concentration of 2.0%, compared to control plants. Additionally, the application of these microalgae extracts improved the quality parameters, proximate composition, seed energy, and mineral contents of the harvested seeds, with the most significant positive impact was observed at 0.5% concentration of algal extract. These findings demonstrate the successful and safe utilization of extracts from C. vulgaris, N. salina, and A. platensis at concentrations up to 1.0% as bio-stimulants to enhance common bean yields and improve the nutritional quality of dried beans for consumers.

Stability and bioactivities evaluation of analytical grade C-phycocyanin during the storage of Spirulina platensis powder.

C-phycocyanin (C-PC) is a natural high-value blue phycobiliprotein from Spirulina platensis, which has wide biological applications in food, pharmaceutical, and cosmetics. However, the freshness of S. platensis powder (SPP) materials and C-PC purification play critical roles in evaluating the stability and bioactivities of C-PC, which severely affect its commercial application. This study investigated the effect of spray-dried SPP freshness on the biofunctional activities of analytical grade C-PC (AGC-PC). The yield of AGC-PC extracted from spray-dried SPP could reach 101.88 mg/g (75% recovery ratio) after purification by reversed phase high-performance liquid chromatography (RP-HPLC) system. The half-life period (t1/2 ) of AGC-PC stability at 60°C and 8000 lux light could remain 171.70 min and 176.11 h within 6 months storage of spray-dried SPP. The emulsifying activity index (EAI) and foaming capacity (FC) of AGC-PC from fresh-dried SPP showed maximum values of 68.64 m2 /g and 252.9%, respectively. The EC50 of AGC-PC from fresh spray-dried SPP on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline -6-sulfonic acid (ABTS+·) scavenging activity could reach 63.76 and 92.93 mg/L, respectively. The EC50 of AGC-PC from fresh spray-dried SPP on proteinase inhibition and anti-lipoxygenase activity were 302.96 and 178.8 mg/L, respectively. The stability and biofunctional activities of AGC-PC remained stable within 6 months storage of SPP, and then rapidly decreased after 9 months storage due to the disintegration of the trimeric (αß)3 and hexameric (αß)6 forms of C-PC. It is concluded that the optimal storage period of SPP for preparation of AGC-PC in commercial use should be less than 6 months. PRACTICAL APPLICATION: The C-phycocyanin (C-PC) from dried Spirulina platensis powder (SPP) has been widely applied in food nutritional, florescent markers, pharmaceuticals, cosmetics, etc, due to its blue color, fluorescence, and antioxidant properties. However, the effect of dried SPP freshness on the stability and functional activity of C-PC has been rarely reported. This study found that the thermostability, photostability, emulsifying, antioxidant, and anti-inflammatory activities of analytical grade C-PC (AGC-PC) significantly decreased after 6 months storage of SPP. Based on investigations, we have proposed that the suitable storage time of dried SPP for preparation of AGC-PC in commercial application should be within 6 months.

The potential of Spirulina platensis to substitute antibiotics in Japanese quail diets: impacts on growth, carcass traits, antioxidant status, blood biochemical parameters, and cecal microorganisms.

The development of antibiotic-resistant microorganisms prompted the investigation of possible antibiotic substitutes. As a result, the purpose of the current study is to assess the effect of dietary Spirulina platensis extract as an antibiotic alternative on Japanese quail (Coturnix japonica) growth, antioxidant status, blood parameters, and cecal microorganisms. There was a total of 150 Japanese quails used in this study, divided equally among 5 experimental groups (10 birds per group with 3 replicates): group 1 (G1) received a basal diet without any S. platensis extract, group 2 (G2) received a basal diet supplemented with 1 mL S. platensis extract/kg, group 3 (G3) received a basal diet supplemented with 2 mL S. platensis extract/kg, group 4 (G4) received a basal diet supplemented with 3 mL S. platensis extract/kg, and group 5 (G5) received a basal diet supplemented with 4 mL S. platensis extract/kg from d 7 until d 35. The results showed that compared to the control birds in G1, Japanese quail supplemented with 4 mL of S. platensis extract/kg of diet (G5) had significantly better live body weight, body weight gain, feed intake, feed conversion ratio, digestive enzymes, blood parameters, liver and kidney functions, lipid profile, antioxidant profile, immunological parameters, and cecal microorganism's count. There were no significant changes in the percentage of carcasses, liver, and total giblets among all the 5 groups. Only gizzard percentage showed a significant increase in G2 compared to birds in G1. In addition, intestinal pH showed a significant drop in G2 and G5 compared to birds in G1. After cooking the quail meat, the juiciness and tenderness increased as S. platensis extract levels increased, whereas aroma and taste declined slightly as S. platensis extract levels increased. Furthermore, when a high concentration of S. platensis extract was used, the lightness of the meat reduced while its redness and yellowness increased. The disk diffusion assay showed that S. platensis extract had significant antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, and Salmonella typhi, with inhibition zones ranging from 16 to 42 mm. This activity may be attributable to the volatile chemicals in S. platensis extract, of which Geosmin and 2-methylisoborneol are the primary components. In the diet of Japanese quails, it is possible to draw the conclusion that the extract of S. platensis can be utilized as a feed additive and as an alternative to antibiotics.