H2O2 Scavenging Research Articles

Qualitative, Quantitative, In Vitro Antioxidant Activity and Chemical Profiling of Leptadenia pyrotechnica (Forssk.) Decne Using Advanced Analytical Techniques.

Leptadenia pyrotechnica Forssk. Decne (LP) is a medicinal herb from the Asclepiadaceae family with many advantageous properties. The goal of this research is to identify, quantify, and evaluate the antioxidant potential of LP to validate its remarkable therapeutic advantages. The hot soxhlet extraction method was employed to prepare different extracts of LP (stem and root). These extracts were evaluated physiochemically to check their impurity, purity, and quality; qualitatively to detect different phytochemicals; and quantitatively for phenol, saponin, tannin, flavonoid, and alkaloid contents. Then, the in vitro antioxidant potential was estimated by DPPH, NO, H2O2 scavenging assays, and MC and FRAP assays. The most prevalent phytochemicals of LP were then analysed by AAS, FT-IR, UV-visible, and GC-MS techniques. A higher extractive yield was shown by LPSE and LPRE (7.37 ± 0.11 and 5.70 ± 0.02). The LP stem showed better physicochemical and qualitative results than the root. The quantitative and in vitro antioxidant results indicated maximal phenols, tannins, and alkaloid contents in LPSE, which was further confirmed by UV-visible, FT-IR, and GC-MS results. The extraction methods (soxhlation or ultrasonication) were optimized by utilizing RSM to determine the impacts of multiple parameters. The study concluded that the plant has remarkable therapeutic advantages to promote additional clinical investigations and the mechanisms of its action.

Controlled Delivery of H2O2: A Three-Enzyme Cascade Flow Reactor for Peroxidase-Catalyzed Reactions.

Peroxidases are promising catalysts for oxidation reactions, yet their practical utility has been hindered by the fact that they require hydrogen peroxide (H2O2), which at high concentrations can cause deactivation of enzymes. Practical processes involving the use of peroxidases require the frequent addition of low concentrations of H2O2. In situ generation of H2O2 can be achieved using oxidase-type enzymes. In this study, a three-enzyme cascade system comprised of a H2O2 generator (glucose oxidase (GOx)), H2O2-dependent enzymes (chloroperoxidase (CPO) or horseradish peroxidase (HRP)), and a H2O2 scavenger (catalase (CAT)) was deployed in a flow reactor. Immobilization of the enzymes on a graphite rod was achieved through electrochemically driven physical adsorption, followed by cross-linking with glutaraldehyde. Modeling studies indicated that the flow in the reactor was laminar (Reynolds number, R e < 2000) and was nearly fully developed at the midplane of the annular reactor. Immobilized CAT and GOx displayed good stability, retaining 79% and 84% of their initial activity, respectively, after three cycles of operation. Conversely, immobilized CPO exhibited a considerable reduction in activity after one use, retaining only 30% of its initial activity. The GOx-CAT-GRE system enabled controlled delivery of H2O2 in a more stable manner with a 4-fold enhancement in the oxidation of indole compared to the direct addition of H2O2. Using CPO in solution coupled with GOx-CAT-GRE yields of 90% for the oxidation of indole to 2-oxyindole and of 93% and 91% for the chlorination of thymol and carvacrol, respectively.

Diurnal-Rhythmic Relationships between Physiological Parameters and Photosynthesis- and Antioxidant-Enzyme Genes Expression in the Raphidophyte Chattonella marina Complex.

Diurnal rhythms in physiological functions contribute to homeostasis in many organisms. Although relationships between molecular biology and diurnal rhythms have been well studied in model organisms like higher plants, those in harmful algal bloom species are poorly understood. Here we measured several physiological parameters and the expression patterns of photosynthesis-related and antioxidant-enzyme genes in the Chattonella marina complex to understand the biological meaning of diurnal rhythm. Under a light-dark cycle, Fv/Fm and expression of psbA, psbD, and 2-Cys prx showed significant increases in the light and decreases during the dark. These rhythms remained even under continuous dark conditions. DCMU suppressed the induction of psbA, psbD, and 2-Cys prx expression under both light regimes. Oxidative stress levels and H2O2 scavenging activities were relatively stable, and there was no significant correlation between H2O2 scavenging activities and antioxidant-enzyme gene expression. These results indicate that the Chattonella marina complex has developed mechanisms for efficient photosynthetic energy production in the light. Our results showed that this species has a diurnal rhythm and a biological clock. These phenomena are thought to contribute to the efficiency of physiological activities centered on photosynthesis and cell growth related to the diurnal vertical movement of this species.

Comparative studies of antioxidant activity and profile of some spices

Compounds that prevent or slow down the oxidation of lipids or other molecules like free radicals are known as antioxidants. The Study evaluated the antioxidant capacity, hydrogen peroxide scavenging capacity, and total flavonoid and phenol contents of six spices. Dried samples of spices were extracted in distilled water and analyzed using spectrophotometric and titrimetric methods. TAC results ranged from 232.79 - 64.32 mg/100g, with clove and black cardamom exhibiting the highest and lowest antioxidant activity respectively. The H2O2 scavenging activities result had clove and rosemary with the highest scavenging activity. Rosemary had the highest total phenol (5060 mg/100g) and flavonoid (1339 mg/100g) contents while black cardamom had the lowest values in both. Spices could be substituted for synthetic antioxidants in the food industry and as dietary sources of natural antioxidants.

Hydrogel-forming viscous liquid in response to ROS restores the gut mucosal barrier of colitis mice via regulating oxidative redox homeostasis

The disrupted oxidative redox homeostasis plays a critical role in the progress of ulcerative colitis (UC). Herein, hydrogel-forming viscous liquid (HSD) composed of cysteamine-grafted hyaluronic acid (HS) and superoxide dismutase (SOD) has been designed for UC. When the viscous HSD liquid was infused into colitis colon, SOD would convert the pathological superoxide (O2·−) to hydrogen peroxides (H2O2), which was subsequently scavenged by HS. Accordingly, the sol-gel transition of HSD was initiated by scavenging H2O2, enhancing its adhesion toward colitis colon. H2O2-treated HSD presented the higher storage modulus and stronger adhesion force toward porcine colon than the untreated HSD. Besides, H2O2-treated HSD presented the slower erosion profile in the colitis-mimicking medium (pH 3-5), while its rapid degradation was displayed in physiologic condition (pH7.4). The combination of pH-resistant erosion and ROS-responsive adhesion for HSD rendered it with the specifical retention on the inflamed colonic mucosa of DSS-induced colitis mice. Rectally administrating HSD could effectively hinder the body weight loss, reduce the disease activity index and improve the colonic shorting of DSS-induced colitis mice. Moreover, the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) were substantially decreased, the colonic epitheliums were well rearranged and the tight junction proteins were greatly recovered after HSD treatment. Besides, HSD also modulated the gut flora, markedly augmenting the abundance of Firmicutes, Barnesiella and Lachnospiraceae. Moreover, HSD treatment could regulate oxidative redox homeostasis via activating Nrf2-HO-1 pathway to reduce ROS and malondialdehyde and upregulate antioxidant enzymes (SOD, GPx and GSH). Collectively, HSD might be a promising therapy for UC treatments. Statement of significanceHerein, a hydrogel-forming viscous liquid (HSD) was designed by cysteamine-grafted hyaluronic acid (HS) and superoxide dismutase (SOD) for UC treatments. When the viscous HSD liquid was infused into a colitis colon, SOD would convert the pathological superoxide to hydrogen peroxides (H2O2), which was subsequently scavenged by HS. Accordingly, the sol-gel transition of HSD was initiated by scavenging H2O2, enhancing its adhesion to the colitis colon. The colonic epitheliums of DSS-induced colitis mice were well rearranged and the tight junction proteins (Zonula-1 and Claudin-5) were greatly recovered after the HSD treatment. Moreover, the HSD treatment could regulate oxidative redox homeostasis via activating the Nrf2-HO-1 pathway to reduce ROS and malondialdehyde and upregulate antioxidant enzymes (SOD, GPx and GSH).

In situ O2-releasing quantum dot composites with enhanced radical scavenging behaviour, biosafety, and broadband UV shielding applications

Understanding the defect-driven photophysics-surface chemistry interplay at the nanoscale further augments new design considerations for active ingredients used in sun-protection, emphasizing affordability, safety, and multi-functionality. Accelerating it, our study unravelled broad-spectrum UV attenuation (250 nm–400 nm) and long-lasting photostability (>5 h) exhibited by in-house fabricated β-cyclodextrin functionalized, oxygen vacancy (VO●) engineered-CeO2(x)/ZnO(1-x) quantum dot composites (Em-C(x)Z(1-x)). A conceptually different strategy was pursued, involving artificially engineering surface VO● defects to modulate the band structure and enhance the molar absorptivity through photogenerated electron-hole separation. Unlike conventional inorganic UV blockers, these QD composites harnessed surface VO● for a self-cascading antioxidant effect, scavenging 62.8 % ●OH radicals. Results indicated that autocatalytic endogenous O2 generation from H2O2 scavenging, accelerated by Ce3+/Ce4+ couple, begets anti-photoaging and sunburn alleviation. Em-C(x)Z(1-x) demonstrated synergistic suppression of oxidative stress development and remarkable cell viability (≥90 %) even under UV irradiation. These underlying principles can be extended to prevent and treat other ROS-induced skin ailments. Incorporating Em-C0.3Z0.7 in commercial sunscreens unveiled a substantial enhancement in overall sun protection and antioxidative efficacy. Thus, it is envisioned that Em-C(x)Z(1-x) holds promise for developing safe, efficacious, and economical sunscreens.

Novel Properties of Old Propranolol-Assessment of Antiglycation Activity through In Vitro and In Silico Approaches.

Hypertension has earned the "silent killer" nickname since it may lead to a number of comorbidities, including diabetes and cardiovascular diseases. Oxidative stress and protein glycation play vital roles in the pathogenesis of hypertension. Several studies have shown that they profoundly account for vascular dysfunction, endothelial damage, and disruption of blood pressure regulatory mechanisms. Of particular note are advanced glycation end products (AGEs). AGEs alter vascular tissues' functional and mechanical properties by binding to receptors for advanced glycation end products (RAGE), stimulating inflammation and free radical-mediated pathways. Propranolol, a nonselective beta-adrenergic receptor antagonist, is one of the most commonly used drugs to treat hypertension and cardiovascular diseases. Our study is the first to analyze propranolol's effects on protein glycoxidation through in vitro and in silico approaches. Bovine serum albumin (BSA) was utilized to evaluate glycoxidation inhibition by propranolol. Propranolol (1 mM) and BSA (0.09 mM) were incubated with different glycating (0.5 M glucose, fructose, and galactose for 6 days and 2.5 mM glyoxal and methylglyoxal for 12 h) or oxidizing agents (chloramine T for 1 h). Biomarkers of protein glycation (Amadori products (APs), β-amyloid (βA), and advanced glycation end products (AGEs)), protein glycoxidation (dityrosine (DT), kynurenine (KYN), and N-formylkynurenine (NFK)), protein oxidation (protein carbonyls (PCs), and advanced oxidation protein products (AOPPs)) were measured by means of colorimetric and fluorimetric methods. The scavenging of reactive oxygen species (hydrogen peroxide, hydroxyl radical, and nitric oxide) and the antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl radical and ferrous ion chelating (FIC) assays)) of propranolol were also evaluated. Additionally, in silico docking was performed to showcase propranolol's interaction with BSA, glycosides, and AGE/RAGE pathway proteins. The products of protein glycation (↓APs, ↓βA, ↓AGEs), glycoxidation (↓DT, ↓KYN, ↓NFK), and oxidation (↓PCs, ↓AOPPs) prominently decreased in the BSA samples with both glycating/oxidizing factors and propranolol. The antiglycoxidant properties of propranolol were similar to those of aminoguanidine, a known protein oxidation inhibitor, and captopril, which is an established antioxidant. Propranolol showed a potent antioxidant activity in the FIC and H2O2 scavenging assays, comparable to aminoguanidine and captopril. In silico analysis indicated propranolol's antiglycative properties during its interaction with BSA, glycosidases, and AGE/RAGE pathway proteins. Our results confirm that propranolol may decrease protein oxidation and glycoxidation in vitro. Additional studies on human and animal models are vital for in vivo verification of propranolol's antiglycation activity, as this discovery might hold the key to the prevention of diabetic complications among cardiology-burdened patients.

A facile bio–inspired route of synthesizing Solanum sisymbriifolium fruit extract mediated silver nanoparticles: Pharmaceutical and environmental aspects

The present research work focused on biological synthesis of silver nanoparticles using Solanum sisymbriifolium aqueous fruit extract (AgNPs@SsFE) and determining their pharmaceutical and environmental aspects for the first time. The phytochemicals extracted from S. sisymbriifolium fruit extract (SsFE) contributed in reducing the average particle size of green synthesized AgNPs@SsFE to 23.17 nm and served as capping agents. Further, when AgNPs@SsFE were characterized using PSA, ZP, FE–SEM, Elemental mapping, EDX, HR–TEM, SAED, FTIR and XRD, exhibited the high colloidal stability, spherical shape and crystalline nature of the nanoparticles. Moreover, the synthesized AgNPs@SsFE exhibited enhanced antioxidant activity in comparison to SsFE when assayed via DPPH, FRAP, •NO and H2O2 scavenging methods. The Agar well–diffusion analysis unveiled AgNPs@SsFE to possess greater antibacterial activity against highly pathogenic gram–negative strains than gram–positive strains. Besides, the synthesized AgNPs@SsFE established itself to be a strong photocatalyst by degrading the methylene blue cationic dye under Solar and UV irradiations. These features of synthesized AgNPs@SsFE are found promising to convince the efficacy of SsFE in synthesizing the nanoparticles which can be useful in modern medicine and clinical applications.

Biofiltering capacity of Chambardia rubens (Bivalvia: Unionidae) may modulate expression of stress and growth genes inhibited by the neonicotinoid insecticide acetamiprid in zebrafish

Neonicotinoid insecticides specifically target insect subtypes of nicotinic acetylcholine receptors. Acetamiprid (ACE: C10H11ClN4), the neonicotinoid insecticide, is used to control crop insect pests worldwide. It is a nitrile, monochloropyridine, and carboxamidine that is highly soluble and accessible to waterways. There, it causes neurotoxic and oxidative perturbance to non-target organisms. The unionid mussel Chamabradia rubens is a common Northern River Nile suspension feeder. The current study aimed to assess ACE filtration from waters by C. rubens, and whether this biological power can reduce ACE effects on fish. Removal of ACE by C. rubens was assessed using LC-MS/MS. Zebrafish Danio rerio adults were exposed to different sublethal doses of ACE in the presence or absence of C. rubens in their aquaria. The results showed that mussels could remove significant ACE amounts from water, where it accumulated mostly in the digestive gland. The presence of C.rubens in zebrafish aquaria having ACE was accompanied by significant upregulation of antioxidant enzyme gene transcripts and total H2O2 scavenging, in contrast to mussel-free ACE-exposed groups. Meanwhile, liver triglycerides rose 5-6-fold in response to ACE in the “Fish-Only” groups, indicating an ACE-induced hepatotoxicity. Also, Insulin-like growth factor 1 (igf1) and fish body mass increased more in “Fish + Mussel” groups than in the “Fish-Only” ones. In aggregate, these findings suggest that the Nile mussel could reduce the oxidative stress and metabolic changes induced in fish by ACE. This can contribute valuable environmental and economic benefits upon the use of this mussel as a biofilter.

Rosmarinic acid, a natural polyphenol, has a potential pro-oxidant risk via NADH-mediated oxidative DNA damage

BackgroundRosmarinic acid (RA) has a wide range of beneficial effects on human health. On the other hand, RA has been reported to induce metal-mediated reactive oxygen species (ROS) generation and DNA damage. However, its mechanism remains unknown. In this study, to clarify the underlying mechanism, we analyzed metal-mediated DNA damage in isolated DNA treated with RA and its analog isorinic acid.ResultsRA plus Cu(II), but not Fe(III), significantly increased 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) formation, an indicator of oxidative DNA damage, in calf thymus DNA. Furthermore, a comparison of the 8-oxodG formation induced by RA and its analog isorinic acid suggested that the catechol groups in RA could be associated with their abilities to form 8-oxodG. Interestingly, the 8-oxodG formation induced by RA and isorinic acid plus Cu(II) was markedly enhanced by the addition of NADH, an endogenous reductant. To elucidate the mechanism of RA plus Cu(II)-induced oxidative DNA damage, we examined DNA damage in 32P-labeled DNA treated with RA in the presence of Cu(II). RA plus Cu(II) caused DNA cleavage, which was enhanced by piperidine treatment, suggesting that RA causes not only DNA strand breakage but also base modification. RA plus Cu(II)-induced DNA damage was inhibited by catalase (H2O2 scavenger), bathocuproine (Cu(I) chelator), and methional (scavenger of a variety of ROS other than •OH) but not by typical •OH scavengers and SOD, indicating the involvement of H2O2, Cu(I), and ROS other than •OH. DNA cleavage site analysis showing RA-induced site-specific DNA damage (frequently at thymine and some cytosine residues) supports the involvement of ROS other than •OH, because •OH causes DNA cleavage without site specificity. Based on these results, Cu(I) and H2O2 generation with concomitant RA autoxidation could lead to the production of Cu(I)-hydroperoxide, which induces oxidative DNA damage. o-Quinone and o-semiquinone radicals are likely to be again reduced to RA by NADH, which dramatically increases oxidative DNA damage, particularly at low concentrations of RA.ConclusionsIn this study, physiologically relevant concentrations of RA effectively induced oxidative DNA damage in isolated DNA through redox cycle reactions with copper and NADH.

RBOH-dependent H2O2 burst induced by silicon dioxide nanoparticles establishes systemic acquired acclimation in quinoa under lead toxicity

The role of silicon dioxide nanoparticles (nSiO2) and hydrogen peroxide (H2O2) in heavy metal tolerance of plants has been well defined; however, their interaction together remains largely unknown. Therefore, two experiments were conducted to determine whether RBOH-dependent signaling is involved in nSiO2-induced systemic lead (Pb) acclimation in Chenopodium quinoa. In the first experiment, quinoa leaves were sprayed with nSiO2 (0, 2, 4 mM) under various Pb concentrations (0, 200 and 400 µM). After 12 h, an H2O2 burst, and higher transcription levels of RBOHD and PCS1 genes (encoding NADPH oxidase and phytochelatin synthase) were recorded in leaves of nSiO2-treated plants. After 15 days, Pb toxicity reduced growth parameters, and Chl a, Chl b contents and increased electrolyte leakage, and foliar spray with nSiO2 reversed this tendency. In the second experiment, foliar application of 4 mM nSiO2 minimized intracellular H2O2 and O2˙¯ and reduced malondialdehyde content and leaf Pb concentration under 400 µM Pb. While, this treatment increased the content of reduced ascorbate, and thiol compounds and enhanced the activities of superoxide dismutase and ascorbate peroxidase not only in leaves but also in untreated roots. However, H2O2 scavenging with DMTU and the inhibition of RBOH-dependent signaling by DPI aggravated Pb phytotoxicity and impaired the beneficial effects of nSiO2 on aforementioned attributes; thereby reduced tolerance index in both leaves and roots. Together, our pharmacological and molecular evidence for the first time unraveled that RBOH-dependent H2O2 burst plays vital role in triggering nSiO2-induced systemic acquired acclimation in Pb-stressed plants.

Mushrooms grown in high-altitude soil exhibiting distinct alterations in growth, biochemical composition and antioxidant potential

Functional foods like mushrooms are high in secondary metabolites and bioactive chemicals with anti-inflammatory, antibacterial, antidiabetic, immune-stimulating and other health-promoting qualities. This study investigates four mushroom varieties including Cordyceps militaris, Pleurotus ostreatus, Pleurotus djamor and Agaricus bisporus, grown on Indian soil and natural environment for measurement of phenol and flavonoid content, along with their antioxidant properties and biochemical makeup. They had a large amount of phenolic and flavonoid content and high DPPH, H2O2 and NO scavenging inhibition percentages, demonstrating strong antioxidant potential. These mushroom extracts also contained a sizable amount of proline and nutritional content like carbohydrate, protein, lipids and fiber. Among all the mushrooms, the biochemical profile was significantly highest. Significant variations were also seen in the amounts of moisture and ash in each sample. This research aimed to determine how mixing soil with compost substrate affected the yield and growth of mushrooms. The soil had a massive impact on forming more mycelial colonies which were necessary for the entire spawn run and spawning to pin head production and for the maturation of pins. It was discovered through this research that combining soil and compost substrate can aid in the growth of good-quality mushrooms and improve their productivity.

A pioneer nematode effector suppresses plant reactive oxygen species burst by interacting with the class III peroxidase.

Bursaphelenchus xylophilus is the pathogen of pine wilt disease, which can devastate the pine forest ecosystem. Usually, plant cells generate reactive oxygen species (ROS)as a defensive substance or signalling molecules to resist the infection of nematodes. However, little is known about how B. xylophilus effectors mediate the plant ROS metabolism. Here, we identified a pioneer B. xylophilus Prx3-interacting effector 1 (BxPIE1)expressed in the dorsal gland cells and the intestine. Silencing of the BxPIE1 gene resulted in reduced nematode reproduction and a delay in disease progression during parasitic stages, with the upregulation of pathogenesis-related (PR)genes PtPR-3(class Ⅳ chitinase) and PtPR-9(peroxidase). The protein-protein interaction assays further demonstrated that BxPIE1 interacts with a Pinus thunbergii class III peroxidase (PtPrx3), which produces H2O2 under biotic stress. The expression of BxPIE1 and PtPrx3 was upregulated during the infection stage. Furthermore, BxPIE1 effectively inhibited H2O2 generating from class III peroxidase and ascorbate can recover the virulence of siBxPIE1-treated B. xylophilus by scavenging H2O2. Taken together, BxPIE1 is an important virulence factor, revealing a novel mechanism utilized by nematodes to suppress plant immunity.

ANTIOXIDANT, ANTI-INFLAMMATORY, ANTIDIABETIC, ANTHELMINTHIC, AND THROMBOLYTIC ACTIVITY OF THE METHANOL EXTRACT OF CITRULLUS LANATUS PEEL

Background: The present study aimed for in vitro evaluation of Citrullus lanatus Peel (CLP) methanol extract for antioxidative, anti-inflammatory, antidiabetic, anthelmintic, and thrombolytic activity. Method: CLP was extracted with methanol and tested for in vitro antioxidative (DPPH and H2O2 scavenging method), thrombolytic, anthelmintic, antidiabetic, and anti-inflammatory properties (human red blood cell membrane stabilization method, α-amylase inhibitory effect by using Iodine-Starch method. Results: The percentage yield was 7% and phytochemical profile showed the presence of steroid, tannins, saponins, flavonoids, glycoside and reducing sugar. In DPPH scavenging assay, 88.7% was at 1000 g/ml, whereas 34% to 48.9% (IC50 27.65 µg/ml) in H2O2 and from 61.8% to 95.2% (IC50 value: 07 µg/ml) in ASCOR. In in vitro anti-inflammatory activity, the maximum protection percentage was observed 58% and 44%. Consecutively, in anti-diabetic activity, IC50 values of 1137.64 μg/ml whereas reference (Acarbose) exhibited IC50 at 671.71 μg/ml. On the other hand, the inhibitory effect of Acarbose showed 57% and 98% respectively at 2000 μg/ml. In earthworms, it considered as very potential for the helminthic infection and helminthiasis. A significant clot lysis activity of 44% was noticed when the clots were treated with 100 µl of CLP extract (10 mg/ml) in in-vitro thrombolytic activity assay. Conclusions: The findings of this study revealed that the peel possessed the antioxidant, anti-inflammatory, antidiabetic, anthelminthic and thrombolytic activities. These findings will be motivated to do further research on molecular level to finds into more depth which is considered as the limitation of this study. Peer Review History: Received 3 February 2024; Revised 12 March 2024; Accepted 20 April; Available online 15 May 2024 Academic Editor: Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, amaka_mgbahurike@yahoo.com Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Dr. Gehan Fawzy Abdel Raoof Kandeel, Pharmacognosy Department, National Research Centre, Dokki, 12622, Giza, Egypt, gehankandeel9@yahoo.com Dr. Francis Adou Yapo, Felix Houphouet Boigny, University of Abidjan, Ivory Coast, fyapo@yahoo.fr

In vitro assessing of Cucumis pubescens Willd. fruit extract for phytochemical, antibacterial, antioxidants and toxicity assays

The Cucumis pubescens Willd. belongs to the family Cucurbitaceae. This is found in its natural habitat as a wild plant. Its fruit extract contains a significant number of phytochemicals, contributing to its antioxidant properties. This fruit is edible and used in various traditional medicines for treating diverse ailments. This study focuses on the phytochemical constituents, antibacterial activity against selected microbes, antioxidant potential, and toxicity to zebrafish embryos, all of which are responsible for imparting the medicinal values of C. pubescens fruit. The ethanolic extract of C. pubescens fruit contains various phytochemical constituents such as alkaloids, flavonoids, glycosides, phenolics, sugar, tannins, terpenoids, coumarins, proteins, and amino acids. The total phenolic content was found to be 27.745 ± 0.4765 GAE a/g extract, the total flavonoids were found to be 36.205 ± 0.3854 TAE b/g extract, and total tannins were found to be 31.478 ± 0.2478 RE c/g extract. The antibacterial activity showed an increase in zone of inhibition on increasing the concentration of fruit extract, with ampicillin serving as positive control. The antioxidant assays such as DPPH, reducing power assay, percentage of molybdenum assay, H2O2 scavenging assay, and nitric oxide assay were performed using 25,50,75,100, and 125 μg/mL concentrations of the fruit extract. The results revealed that increasing the concentration of the fruit extract and increased the antioxidant activity up to 95 % at higher concentrations. The mortality rate of zebrafish embryo confirmed the nontoxic nature of C. pubescens fruit extract at different concentrations, observed at 24,48,72, and 98 h. This work highlights the presence of phytochemicals in C. pubescens ethanolic fruit extract, which are responsible for its greater antibacterial and antioxidant activities, and exhibits its nontoxicity on the zebrafish embryo model.

Crosstalk between H2O2 and Ca2+ signaling is involved in root endophyte-enhanced tanshinone biosynthesis of Salvia miltiorrhiza

Tanshinones are bioactive ingredients derived from the herbal plant Salvia miltiorrhiza and are used for treating diseases of the heart and brain, thus ensuring quality of S. miltiorrhiza is paramount. Applying the endophytic fungus Trichoderma atroviride D16 can significantly increase the content of tanshinones in S. miltiorrhiza, but the potential mechanism remains unknown. In the present study, the colonization of D16 effectively enhanced the levels of Ca2+ and H2O2 in the roots of S. miltiorrhiza, which is positively correlated with increased tanshinones accumulation. Further experiments found that the treatment of plantlets with Ca2+ channel blocker (LaCl3) or H2O2 scavenger (DMTU) blocked D16-promoted tanshinones production. LaCl3 suppressed not only the D16-induced tanshinones accumulation but also the induced Ca2+ and H2O2 generation; nevertheless, DMTU did not significantly inhibit the induced Ca2+ biosynthesis, implying that Ca2+ acted upstream in H2O2 production. These results were confirmed by observations that S. miltiorrhiza treated with D16, CaCl2, and D16+LaCl3 exhibit H2O2 accumulation and influx in the roots. Moreover, H2O2 as a downstream signal of Ca2+ is involved in D16 enhanced tanshinones synthesis by inducing the expression of genes related to the biosynthesis of tanshinones, such as DXR, HMGR, GGPPS, CPS, KSL and CYP76AH1 genes. Transcriptomic analysis further supported that D16 activated the transcriptional responses related to Ca2+ and H2O2 production and tanshinones synthesis in S. miltiorrhiza seedlings. This is the first report that Ca2+ and H2O2 play important roles in regulating fungal-plant interactions thus improving the quality in the D16-S. miltiorrhiza system.

Effect of dietary seaweed Caulerpa racemosa on growth, biochemical, non-specific immunity, and disease resistance to Pseudomonas aeruginosa in Cirrhinus mrigala

BackgroundThe green seaweed Caulerpa racemosa possesses highly potential elements in animal forages and human use since ancient times. The current study was designed to investigate the antioxidants, phytochemical properties of C. racemosa, as well as their effects on growth parameters, biochemical components, non-specific immunological parameters, and disease resistance to P. aeruginosa in Cirrhinus mrigala. The experimental group, divided into five groups as T1–T5. T2–T5, was given C. racemosa extract at concentrations of 0.5%, 2.5%, 4.5%, & 6.5% supplemented with basal diets. T1's group food is devoid of extract and acts as a control, and the trial lasted forty-five days.ResultsC. racemosa exhibited dose-dependent antioxidant activity. The highest levels of DPPH (61.21%), ABTS (70.55%), and H2O2 (66.55%) scavenging activities were obtained at 100 µg/ml 100 μg/ml. GC–MS analysis revealed phytoconstituents in the crude extract, such as palmitolinoleic acid, butanoic acid, arachidonate, linoleic acid, vaccenic acid, octadecenoic acid, trans-phytol, and eicosanoids. Among these different concentrations, 4.5% C. racemosa supplemented diet produced a significantly higher growth metrics of C. mrigala’s (WG, SGR, FCR), biochemical constituents, when compared to other concentrations. In a post-challenge trial, 4.5% C. racemosa extract meals increased C. mrigala SOD, CAT, non-specific immune response (lysozyme, NBT, phagocytic activity), and haematological (RBC, WBC, HCT & Hb) parameters when compared to other experiments.ConclusionsThe findings revealed that 4.5% of C. racemosa may be supplied in the diet of C. mrigala to regulate better survival growth performance and haematological parameters.

A multilevel investigation to reveal the regulatory mechanism of lignin accumulation in juice sac granulation of pomelo

Granulation of juice sacs is a physiological disorder, which affects pomelo fruit quality. Here, the transcriptome and ubiquitinome of the granulated juice sacs were analyzed in Guanxi pomelo. We found that lignin accumulation in the granulated juice sacs was regulated at transcription and protein modification levels. In transcriptome data, we found that the genes in lignin biosynthesis pathway and antioxidant enzyme system of the granulated juice sacs were significantly upregulated. However, in ubiquitinome data, we found that ubiquitinated antioxidant enzymes increased in abundance but the enzyme activities decreased after the modification, which gave rise to reactive oxygen species (ROS) contents in granulated juice sacs. This finding suggests that ubiquitination level of the antioxidant enzymes is negatively correlated with the enzyme activities. Increased H2O2 is considered to be a signaling molecule to activate the key gene expressions in lignin biosynthesis pathway, which leads to the lignification in granulated juice sacs of pomelo. This regulatory mechanism in juice sac granulation of pomelo was further confirmed through the verification experiment using tissue culture by adding H2O2 or dimethylthiourea (DMTU). Our findings suggest that scavenging H2O2 and other ROS are important for reducing lignin accumulation, alleviating juice sac granulation and improving pomelo fruit quality.

Visualizing hydrogen peroxide and nitric oxide dynamics in endothelial cells using multispectral imaging under controlled oxygen conditions

The complex interplay between hydrogen peroxide (H2O2) and nitric oxide (NO) in endothelial cells presents challenges due to technical limitations in simultaneous measurement, hindering the elucidation of their direct relationship. Previous studies have yielded conflicting findings regarding the impact of H2O2 on NO production. To address this problem, we employed genetically encoded biosensors, HyPer7 for H2O2 and geNOps for NO, allowing simultaneous imaging in single endothelial cells. Optimization strategies were implemented to enhance biosensor performance, including camera binning, temperature regulation, and environmental adjustments to mimic physiological normoxia. Our results demonstrate that under ambient oxygen conditions, H2O2 exhibited no significant influence on NO production. Subsequent exploration under physiological normoxia (5 kPa O2) revealed distinct oxidative stress levels characterized by reduced basal HyPer7 signals, enhanced H2O2 scavenging kinetics, and altered responses to pharmacological treatment. Investigation of the relationship between H2O2 and NO under varying oxygen conditions revealed a lack of NO response to H2O2 under hyperoxia (18 kPa O2) but a modest NO response under physiological normoxia (5 kPa O2). Importantly, the NO response was attenuated by l-NAME, suggesting activation of eNOS by endogenous H2O2 generation upon auranofin treatment. Our study highlights the intricate interplay between H2O2 and NO within the endothelial EA.hy926 cell line, emphasizing the necessity for additional research within physiological contexts due to differential response observed under physiological normoxia (5 kPa O2). This further investigation is essential for a comprehensive understanding of the H2O2 and NO signaling considering the physiological effects of ambient O2 levels involved.

Comprehensive evaluation of Ixoroside: An iridoid glycoside from Nepeta aristata and N. baytopii, assessing antioxidant, antimicrobial, enzyme inhibitory, DNA protective properties, with computational and pharmacokinetic analyses

Ixoroside, an iridoid glycoside, was isolated from two endemic plants, Nepeta aristata and Nepeta baytopii and its structure was elucidated by comprehensive analysis with NMR and mass spectrophotometers. It was observed that the compound exhibited strong antioxidant activity in phosphomolybdenum-reducing power (55.65±0.02 μg/mL), H2O2 (2.97±0.50 μg/mL), and superoxide anion scavenging (11.31±0.19 μg/mL) activities. It has also been noted that the ixoroside molecule has enzyme inhibitor (7.01±0.001 μg/mL for urease, 19.06±0.51 μg/mL for AChE, 9.90±0.5 μg/mL for BChE, 16.87±0.08 μg/mL for α-amylase, 4.11±0.36 μg/mL for α-glucosidase and 2.23±0.001 μg/mL for tyrosinase) and DNA protective effect (55.14% for Form I) and antibacterial (10 mm against K. pneumoniae, 9.00 mm against E. faecalis and 11.00 mm against S. aureus, 128 μg/mL against E. coli and E. faecalis). In silico studies, density functional theory (DFT) and molecular docking were performed to elucidate ixoroside interaction with enzymes. In enzyme inhibition kinetics, ixoroside exhibited strong interaction with urease (Ki, 0.11 mM, mixed-uncompetitive), α-glucosidase (Ki, 0.10 mM, noncompetitive) and tyrosinase (Ki, 0.10 mM, noncompetitive). Additionally, BChE was observed to interact strongly with α-glucosidase and tyrosinase with binding constants of 0.49, 1.19 and 3.15 μM in molecular docking. Moreover, the pharmacological properties of ixoroside examined by adsorption, distribution, metabolism, excretion and toxicity (ADMET) showed that the molecule has drug-like properties.