Reactive Oxygen Species Scavenging Potential Research Articles

Antioxidant and enzyme inhibitory potentials of phytochemicals isolated from Dioclea reflexa (Hook F.) stem: in-vitro and in-silico studies

The objective of the study was to isolate and characterize phytochemicals from the stem extract of D. reflexa and investigate their biochemical activities. Five flavonoids together with two terpenoids, were isolated. Their structures were identified using 1D and 2D nuclear magnetic resonance (NMR) and mass spectroscopic techniques in combination with circular dichroism (CD) spectroscopy, as well as comparisons with published data. The in vitro reactive oxygen species scavenging potential of the compounds was investigated. The lipoxygenase and urease inhibitory potential of the compounds were tested using in vitro and in silico methods. Compound 1 and 2 exhibited potent antioxidant activity with lower IC50 values of 38.5 ± 0.25 and 39.5± 0.14 μM respectively compared with the standard used (BHA IC50 value = 39.5± 0.14) in DPPH assay. Compound 1 and 2 also exhibit good reducing ability and superoxide radical scavenging activity reflected by IC50 value 44.6 ± 0.30 and 48.5 ± 0.16 respectively compared with BHA (IC50 45.6 ± 0.54). Compound 2 and 3 showed significant inhibitory effect against urease with IC50 values 26.2 ± 0.29 μM and 36.5 ± 0.37 μM respectively, while compound 4 with IC50 value 33.3 ± 0.74 μM is the most active against lipoxygenase. All the seven compounds showed varying degrees of binding affinity against the targets with compounds 1–5 having the better docking score compared with the co-crystalized ligands of both lipoxygenase and urease. The density functional theory reveals the replicate of the transitional state between the compounds and their respective receptor and stability of the compounds was predicted from the energy gap (ELUMO – EHOMO). These compounds are potential drug against stomach ulcers, inflammation and oxidative stress associated diseases. It is also worth mentioning that the complete assignments of NMR data 1 and 2 were reported for the first time in this study.

A study on phytochemical profiling of Avicennia marina mangrove leaves collected from Indian Sundarbans

Mangroves are the most diverse and productive ecosystem that is enriched with various classes of phytochemicals having potential medicinal applications. Here we have studied the bioactive potential and the presence of secondary metabolites in Avicennia marina, one of the dominant species in the Indian Sundarbans mangrove habitat. The bioactive potential study of A. marina was carried out in terms of the determination of total phenolic content, total flavonoid content and reactive oxygen species scavenging potential. The methanolic and ethyl acetate extracts were subjected to Fourier transform infrared spectroscopy (FTIR) for functional group identification. Further, detailed phytochemical profiling has been carried out by liquid chromatography-mass spectrometry (LC-MS). The Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) values for the methanolic extract of A. marina leaves were 148.0 mg GAE g−1 dry extract and 251.9 mg CE g−1 dry extract which was higher than ethyl acetate extracts. The free radical scavenging potential showed that methanolic extract of A. marina leaves can scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical up to 96.0 % and ethyl acetate extract can scavenge up to 73.7 % at 250 µg mL−1. LC-MS metabolic profile revealed the presence of different classes of secondary metabolites like fatty acids, flavonoids, plant hormones, etc., in methanolic extract. The presence of different classes of phytochemicals in the methanolic extract proves its potential as a source of plant-derived medicinal compounds.

Glucose metabolic reprogramming and modulation in glycerol biosynthesis regulates drug resistance in clinical isolates of Candida.

The study is aimed at understanding the novel molecular mechanisms governing drug resistance in the opportunistic fungi belonging to the genus Candida. This is a multipronged study wherein different assays like drug susceptibility and whole cell proteome analysis, stress tolerance assay, measurement of total internal glycerol content, western blot analysis, reactive oxygen species (ROS) measurement, glucose uptake, lactate production, ATP generation, and NADPH measurements were made.The study reveals an incidence of different species of Candida in the northern most part of India (Kashmir valley). Resistant isolates, mostly resistant to azoles were reported across all the species. The study revealed a difference in resistance mechanisms between Candida albicans and C. glabrata clinical isolates. Further, such resistance mechanism (in the case of C. albicans) was mostly mediated by Hexokinase 2 (Hxk2) and Glucose-6-phosphate dehydrogenase (G6pd). Increased expression of Hxk2 was associated with increased glucose uptake, more lactate production, and more ATP generation in drug-resistant C. albicans. At the same time, increased G6pd expression was responsible for the increased production of NADPH, which imparts a better ROS scavenging potential. While in C. glabrata the resistance was linked with glycerol metabolism, where the drug-resistant isolate tends to accumulate more glycerol as an osmolyte in response to external stresses. This glycerol accumulation was found to be triggered by the HOG1-MAPK pathway. The study concludes that, like various human malignant tumors, there is a strong correlation between drug resistance and aberrant cellular metabolism in the opportunistic fungi belonging to the genus Candida.

ROS-responsive PPGF nanofiber membrane as a drug delivery system for long-term drug release in attenuation of osteoarthritis

Excessive reactive oxygen species (ROS) are one of the leading mechanisms in the initiation and development of osteoarthritis (OA). However, conventional injection of ROS-responsive drug delivery systems (DDSs) such as nanoparticles and hydrogels usually cannot provide effective treatment due to rapid clearance and degradation or low bioavailability. In this study, a ROS-responsive nanofiber membrane named PLA/PEGDA-EDT@rGO-Fucoxanthin (PPGF) is fabricated by electrospinning, wherein PEGDA-EDT served as the ROS-responsive motif, reduced graphene oxide (rGO) as the drug carrier and fucoxanthin (Fx) as the antioxidative and anti-inflammatory agent. The results demonstrated that the PPGF nanofiber membrane exhibited sustained and long-term Fx release behavior (at least 66 days) in response to hydrogen peroxide (H2O2) in vitro. With low cytotoxicity and smart ROS responsiveness, PPGF showed excellent anti-inflammatory and antioxidative effects on IL-1β-induced chondrocytes by potent ROS scavenging potential and upregulation of antioxidative enzymes. It also demonstrated the attenuation of OA progression with the reduced Osteoarthritis Research Society International (OARSI) score by 93.17% in 8 weeks. The smart ROS-responsive, biodegradable and biocompatible nanofiber membranes possess great potential for OA therapy under arthroscopy.

DEVELOPMENT AND OPTIMIZATION OF MANNOSYLATED NARINGENIN LOADED TRANSFERSOMES USING RESPONSE SURFACE METHODOLOGY FOR SKIN CARCINOMA

Objective: The flavonoidal drug Naringenin offers a natural defense against free radical generation due to their antioxidant i.e. free radical scavenging property. The continuation of research work towards the invention of targeting the flavonoidal drug for skin carcinoma. Naringenin is a potent antioxidant, having remarkable reactive oxygen species scavenging potential and abundantly found in citrus fruits.
 Methods: The optimization of the formulated mannosylated naringenin-loaded transfersomes (MA-NgTfs) was performed using Box–Behnken statistical design to obtain crucial variable parameters that influence vesicular size, size distribution and surface charge. Therefore keeping both the concepts in mind our objective is to design and optimize the mannosylated naringenin loaded transfersomes (MA-NgTfs) for macropahge targeting. The Box Behnken with 3D surface response design graph was employed to optimize the formulation.
 Results: Phospholipids and surfactant ratio played a remarkable role to determine the mean vesicular size and the Zeta potential of the vesicles. The Zeta potential is found in the formulation having a range of-18.01±1.05 to-28.7±1.008 mV represents the good stability of the formulation. The vesicles size range was found in the range of 102.4±1.01 to 263.74±0.63 and range of Entrapment efficiency of nanovesicles was as 72.04±1.53 to 82.04±0.81. In vitro drug release study shows that mannosylated naringenin loaded transfersomes (MA-NgTfs), and marketed formulation dispersion was found 69.31 %, 62.03 %, 58.71 %, and 65.02 % respectively. Ex vivo skin permeation and deposition study shows that the marketed product and pure drug suspension optimized transfersomes through the skin of mice was of flux 6.5±3.07 and the percentage of drug retention was 0.76±1.26. The results gave us strong evidence of cellular uptake bymannose–directed transfersomes via mannose receptor-based endocytosis.
 Conclusion: On the basis of findings, the study revealed that the prepared formulation has characteristic potential for targeting and the concept of ligand directed nanocarrier formulation was imparts synergistic effect against UV-induced skin carcinoma.

Antioxidant Potential of Sulfated Polysaccharides from Padina boryana; Protective Effect against Oxidative Stress in In Vitro and In Vivo Zebrafish Model.

Elevated levels of reactive oxygen species (ROS) damage the internal cell components. Padina boryana, a brown alga from the Maldives, was subjected to polysaccharide extraction. The Celluclast enzyme assisted extract (PBE) and ethanol precipitation (PBP) of P. boryana were assessed against hydrogen peroxide (H2O2) induced cell damage and zebra fish models. PBP which contains the majority of sulfated polysaccharides based on fucoidan, showed outstanding extracellular ROS scavenging potential against H2O2. PBP significantly declined the intracellular ROS levels, and exhibited protection against apoptosis. The study revealed PBPs’ ability to activate the Nrf2/Keap1 signaling pathway, consequently initiating downstream elements such that catalase (CAT) and superoxide dismutase (SOD). Further, ROS levels, lipid peroxidation values in zebrafish studies were declined with the pre-treatment of PBP. Collectively, the results obtained in the study suggest the polysaccharides from P. boryana might be a potent source of water soluble natural antioxidants that could be sustainably utilized in the industrial applications.

Abstract A066: Role of the NRF2 signaling pathway in sustaining chemoresistance in medulloblastoma

Abstract Nrf2, a key orchestrator of cell defense mechanisms against oxidative stress and xenobiotic insults, has been linked to chemotherapy resistance and recurrence in many human cancers. Through the establishment of an in vitro model of chemoresistance, we investigated the role of Nrf2 in sustaining resistance to chemotherapy in medulloblastoma (MB), a highly aggressive pediatric brain tumor intrinsically characterized by fast growth, high invasiveness and resistance to treatments. MB DAOY cells were weekly exposed to a cocktail of drugs commonly used in MB treatment, vincristine, etoposide, cisplatin and cyclophosphamide (VECC) inducing the emergence of a resistant phenotype. After 5 cycles of VECC treatment we obtained a culture of cells resistant to subsequent chemotherapy treatments. We observed increased Nrf2 levels and activity in therapy-exposed cells already from the first received dose of VECC. Nrf2 levels remained high throughout all the rest of chemotherapy cycles and interestingly, its transcriptional activity spiked up when resistance to chemotherapy emerged, as demonstrated by the increase of antioxidant response element (ARE)-driven luciferase activity and the expression of target genes. The knock down of Nrf2 in resistant cells, by the use of specific siRNA, was able to restore chemosensitivity, suggesting a role of Nrf2 signaling pathway in the onset of chemotherapy resistance in MB cells. Resistant cells showed a higher ROS (reactive oxygen species) scavenging capacity after stimulation with hydrogen peroxide. Nrf2 silencing partially reverts the ability of resistant cells to manage oxidative stress, supporting the hypothesis of Nrf2 involvement in the ROS scavenging potential of VECC resistant MB cells. In addition to directly regulate ROS-scavenging enzymes, Nrf2 has been described to control cell metabolism that maintain redox homeostasis in cancer stem cells. Among the Nrf2 target genes upregulated in DAOY resistant cells we found the upregulation of PFKFB-3, G6PD and TKT. The increased expression of this enzymes suggests a metabolic reprogramming in resistant cells. Our data support the involvement of Nrf2 pathway in MB response to VECC treatment and show that the upregulation of this detoxifying system sustains MB resistance to chemotherapy. Citation Format: Fatlum Rruga, Elena Mariotto, Luca Persano, Elena Rampazzo, Alessandra Luchini, Lance A Liotta, Giampietro Viola, Roberta Bortolozzi. Role of the NRF2 signaling pathway in sustaining chemoresistance in medulloblastoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A066. doi:10.1158/1535-7163.TARG-19-A066

Identification and comparison of the volatile constituents of fresh and dried leaves of Spondias mombin found in North-central Nigeria: in vitro evaluation of their cytotoxic and antioxidant activities

Context: Various studies have shown that the leaf extracts of Spondias mombin Linn (Anacardiaceae) possess pharmacological properties such as antioxidant and antiviral effects. However, no biological activity from its essential oil has been reported in literature.Objective: To analyse the chemical constituents, cytotoxic activity and antioxidant capability of the essential oils from fresh and dried leaves of S. mombin.Materials and methods: Hydrodistillation using Clevenger-type apparatus was employed to obtain the essential oil. Oil analysis was performed using an HP 6890 Gas Chromatograph coupled with an HP 5973 Mass Selective Detector. The cytotoxicity bioassay was carried out using the brine shrimp lethality test (10,000–0.01 μg/mL). Additionally, the reactive oxygen species scavenging potential of the two S. mombin oils (1000–200 μg/mL) were investigated using a hydroxyl radical scavenging and ferric iron reducing system.Results: Chemical analysis of essential oils from S. mombin revealed the presence of 41 compounds, with predominance of monoterpenoids, sesquiterpenoids and non-terpenoids derivatives. In both fractions, the principal component was β-caryophellene (27.9–30.9%), followed by γ-cadinene (9.7–12.3%). There was an increase in the oxygenated monoterpenoid contents and a concomitant decrease in the amounts of sesquiterpenoids hydrocarbons observed on drying the leaves. The oil obtained from the fresh leaves was more active than that obtained from dried leaves, with LC50 values (from the brine shrimp lethality assay) of 0.01 and 4.78 μg/mL, respectively. The two oils (from fresh and dried leaves) at 1.0 mg/mL scavenged hydroxyl radical by 83% and 99.8%, respectively. Moreover, they reduced ferric ion significantly and compared favourably with vitamin C.Conclusions: Essential oil derived from the leaves of S. mombin could hold promise for future application in the treatment of cancer-related diseases.

Juniperus chinensis and the functional compounds, cedrol and widdrol, ameliorate α-melanocyte stimulating hormone-induced melanin formation in B16F10 cells

Anti-melanogenic activities of Juniperus chinensis methanol extracts (JCM) and isolation of functional compounds were investigated. JCM possessed potent anti-oxidative and tyrosinase inhibitory activities. α-Melanocyte stimulating hormone (α-MSH)-induced melanogenesis and tyrosinase activity were inhibited by JCM in B16F10 cells. JCM also possessed potent scavenging activities against hydrogen peroxide induced reactive oxygen species (ROS). The dichloromethane (CH2Cl2) solvent fraction only exhibited an anti-melanogenic activity with a potent ROS scavenging potential. The main compounds in the CH2Cl2 fraction were cedrol (CR) and widdrol (WR), which inhibited melanogenesis both individually and synergistically. As the results, J. chinensis possesses potent anti-oxidative and anti-melanogenic activities due to active compounds, CR and WR. J. chinensis, CR, and WR provide promising new strategies for anti-oxidative and depigmenting resources.

Antioxidant nanozyme: a facile synthesis and evaluation of the reactive oxygen species scavenging potential of nanoceria encapsulated albumin nanoparticles.

Several diseases and disorders, including cancer are endorsed by excessive oxidative stress caused due to the incomplete removal of reactive oxygen species (ROS) by the antioxidant defense system of the body. Therefore, present interest among the scientific community lies in the development of a highly stable, biocompatible artificial enzymatic system that possesses a high ROS scavenging activity over a period of time. In recent years, catalytic nanoparticles emerged as a potential candidate in the field of nanomedicine. Due to their inherent catalytic properties, they are exploited as an artificial enzyme (nanozyme), to reinstate or correct aberrant enzymatic activities in patients. Among them, cerium oxide nanoparticles/nanoceria (CNPs) emerged as a potent artificial redox enzyme, mimicking the activity of superoxide dismutase (SOD) and catalase and endure a tremendous ROS scavenging potential as depicted in a surfeit of human cell lines and animal models. In the present article, a facile synthesis of biocompatible nanoceria encapsulated albumin nanoparticles (BCNPs) via desolvation technique that lead to the abatement of intracellular ROS is reported. Physico-chemical characterizations of as-prepared BCNPs corroborate the formation of a highly monodispersed, spherical and stable aqueous delivery system. Interestingly, such entrapment does not affect the enzyme mimetic activity of CNPs, as demonstrated by SOD assay. The biocompatibility and ROS scavenging potential of BCNPs were further assessed in vitro against human lung epithelial cells by cell viability assay and flow cytometric analysis, respectively. The quantitative and qualitative assessments of cellular uptake of BCNPs were done by inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) analysis. Furthermore, the BCNPs preserve the cell's antioxidant defense system and protect them from oxidant-mediated apoptosis as confirmed by semi-quantitative RT-PCR analysis. Thus, the as-prepared BCNPs could provide an opportunity to be utilized as a potential candidate against ROS induced diseases and disorders.

Bridelia ferruginea Promotes Reactive Oxygen Species Detoxification in N-Nitrosodiethylamine-Treated Rats

ABSTRACTThis study was aimed at investigating the in vitro and in vivo reactive oxygen species (ROS) scavenging and detoxification potentials of aqueous extract of Bridelia ferruginea (B. ferruginea). Reactive oxygen species scavenging potentials of the aqueous leaf extract of B. ferruginea (0.2–1.0 mg/ml) was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, hydroxyl radical, and ferric ion reducing system. The detoxification of ROS was evaluated in N-nitrosodiethylamine-induced redox imbalance in the liver of rats. B. ferruginea extract at 1.0 mg/ml scavenged the DPPH, superoxide ion, hydrogen peroxide, and hydroxyl radical at 87%, 83%, 92%, and 86%, respectively, it also reduced ferric ion significantly. ROS detoxifying enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, and glucose 6-phosphate dehydrogenase) activities were significantly (p < .05) induced by B. ferruginea. These inductions significantly ( p < .05) attenuated the N-nitrosodiethylamine-mediated decrease in ROS detoxifying enzymes and compared favorably with Vitamin C. N-nitrosodiethylamine-mediated elevation in the concentrations of malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and percentage DNA fragmentation were significantly (p < .05) lowered by B. ferruginea extract. Overall, the results of this study show that B. ferruginea leaf extract possess ROS scavenging and detoxification potentials.

Polyphenolic extract of Blighia sapida arilli prevents N-nitrosodiethylamine-mediated oxidative onslaught on microsomal protein, lipid and DNA

Abstract Polyphenolic extract of Blighia sapida arilli was evaluated for reactive oxygen species (ROS) scavenging and detoxification potentials in rat microsomes. ROS scavenging potentials of the polyphenolic extract of B. sapida (0.2–1.0 mg/mL) was investigated using DPPH radical, superoxide anion radical, hydrogen peroxide, hydroxyl radical and ferric ion reducing system. The detoxification of ROS was evaluated in N-nitrosodiethylamine-induced redox imbalance in rat microsomes. B. sapida polyphenolic extract (1.0 mg/mL) scavenged DPPH, superoxide anion radical, hydrogen peroxide, and hydroxyl radical by 60, 67, 63, and 57%, respectively, while ferric ion was significantly reduced. N-nitrosodiethylamine-mediated decrease in the activities of ROS detoxifying enzymes was significantly (P