scholarly journals Re-routing photosynthetic energy for continuous hydrogen production in vivo

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Oren Ben-Zvi ◽  
Eyal Dafni ◽  
Yael Feldman ◽  
Iftach Yacoby
Keyword(s):  
Hydrogen Production ◽  
Electron Flow ◽  
Reducing Power ◽  
Full Potential ◽  
Oxygen Production ◽  
Sustainable Resources ◽  
Production Of Hydrogen ◽  
Enzyme Superoxide Dismutase

Abstract Background Hydrogen is considered a promising energy vector that can be produced from sustainable resources such as sunlight and water. In green algae, such as Chlamydomonas reinhardtii, photoproduction of hydrogen is catalyzed by the enzyme [FeFe]-hydrogenase (HydA). Although highly efficient, this process is transitory and thought to serve as a release valve for excess reducing power. Up to date, prolonged production of hydrogen was achieved by the deprivation of either nutrients or light, thus, hindering the full potential of photosynthetic hydrogen production. Previously we showed that the enzyme superoxide dismutase (SOD) can enhance HydA activity in vitro, specifically when tied together to a fusion protein. Results In this work, we explored the in vivo hydrogen production phenotype of HydA–SOD fusion. We found a sustained hydrogen production, which is dependent on linear electron flow, although other pathways feed it as well. In addition, other characteristics such as slower growth and oxygen production were also observed in Hyd–SOD-expressing algae. Conclusions The Hyd–SOD fusion manages to outcompete the Calvin–Benson cycle, allowing sustained hydrogen production for up to 14 days in non-limiting conditions.

Antioxidant Activity, Phenolic Content and Hematoprotective Effects of Cleome arabica Polyphenolic Leaf Extract

2019 ◽  
Author(s):  
C. Tigrine ◽  
A. Kameli
Keyword(s):  
Antioxidant Activity ◽  
Biological Effects ◽  
Reducing Power ◽  
Hematological Toxicity ◽  
Protective Effects ◽  
Ferrous Ions ◽  
Polyphenolic Extract ◽  
Cleome Arabica

In this study a polyphenolic extract from Cleome arabica leaves (CALE) was investigated for its antioxidant activity in vitro using DPPH•, metal chelating and reducing power methods and for its protective effects against AraC-induced hematological toxicity in vivo using Balb C mice. Results indicated that CALE exhibited a strong and dose-dependent scavenging activity against the DPPH• free radical (IC50 = 4.88 μg/ml) and a high reducing power activity (EC50 = 4.85 μg/ml). Furthermore, it showed a good chelating effects against ferrous ions (IC50 = 377.75 μg/ml). The analysis of blood showed that subcutaneous injection of AraC (50 mg/kg) to mice during three consecutive days caused a significant myelosupression (P < 0.05). The combination of CALE and AraC protected blood cells from a veritable toxicity. Where, the number of the red cells, the amount of hemoglobin and the percentage of the hematocrite were significantly high. On the other hand, AraC cause an elevation of body temperature (39 °C) in mice. However, the temperature of the group treated with CALE and AraC remained normal and did not exceed 37.5 °C. The observed biological effects of CALE, in vitro as well as in vivo, could be due to the high polyphenol and flavonoid contents. In addition, the antioxidant activity of CALE suggested to be responsible for its hematoprotective effect.

scholarly journals Hepatoprotective studies on methanolic extract fractions of Lindernia ciliata and development of qualitative analytical profile for the bioactive extract

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Praneetha Pallerla ◽  
Narsimha Reddy Yellu ◽  
Ravi Kumar Bobbala
Keyword(s):  
Methanolic Extract ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Liver Homogenate ◽  
Reducing Power ◽  
Hepatoprotective Activity ◽  
Total Phenolic ◽  
Effective Fraction

Abstract Background The objective of the study is to evaluate the hepatoprotective activity of methanolic extract fractions of Lindernia ciliata (LC) and development of qualitative analytical profile of the bioactive fraction using HPLC fingerprinting analysis. All the fractions of methanolic extract of Lindernia ciliata (LCME) are assessed for their total phenolic, flavonoid contents and in vitro antioxidant properties by using DPPH, superoxide, nitric oxide, hydroxyl radical scavenging activities and reducing power assay. Acute toxicity study was conducted for all the fractions and the two test doses 50 and 100 mg/kg were selected for the hepatoprotective study. Liver damage was induced in different groups of rats by administering 3 g/kg.b.w.p.o. paracetamol and the effect of fractions were tested for hepatoprotective potential by evaluating serum biochemical parameters and histology of liver of rats. The effective fraction was evaluated for its antihepatotoxic activity against D-Galactosamine (400 mg/kg b.w. i.p.) and in vivo antioxidant parameters viz., Glutathione (GSH), Melondialdehyde (MDA) and Catalase (CAT) levels are estimated using liver homogenate. Results Among all the fractions, butanone fraction of LCME, (BNF-LCME) has shown better hepatoprotective activity and hence it is selected to evaluate the antihepatotoxicity against D-GaIN. The activity of BNF-LCME is well supported in in vitro and in vivo antioxidant studies and may be attributed to flavonoidal, phenolic compounds present in the fraction. Hence, BNF-LCME was subjected to the development of qualitative analytical profile using HPLC finger printing analysis. Conclusions All the fractions of LCME exhibited significant hepatoprotective activity and BNF-LCME (50 mg/kg) was identified as the most effective fraction.

Nanostructured Ethosomal Gel Loaded with Arctostaphylos uva-ursi extract; In-vitro/In-vivo Evaluation as a Cosmeceutical Product

2021 ◽  
Vol 18 ◽  
Author(s):  
Nayla Javed ◽  
Shakeel Ijaz ◽  
Naveed Akhtar ◽  
Haji Muhammad Shoaib Khan
Keyword(s):  
Zeta Potential ◽  
Biological Activities ◽  
Skin Permeation ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Potential Candidate ◽  
Skin Rejuvenation ◽  
In Vivo Evaluation

Background: Arctostaphylos uva-ursi (AUU) being rich in polyphenols and arbutin is known to have promising biological activities and can be a potential candidate as a cosmaceutical. Ethosomes encourage the formation of lamellar-shaped vesicles with improved solubility and entrapment of many drugs including plant extracts. Objective: The objective of this work was to develop an optimized nanostructured ethosomal gel formulation loaded with AUU extract and evaluated for skin rejuvenation and depigmentation. Methods: AUU extract was tested for phenolic and flavonoid content, radical scavenging potential, reducing power activity, and in-vitro SPF (sun protection factor) estimation. AUU loaded 12 formulations were prepared and characterized by SEM (scanning electron microscopy), vesicular size, zeta potential, and entrapment efficiency (%EE). The optimized formulation was subjected to non-invasive in-vivo investigations after incorporating it into the gel system and ensuring its stability and skin permeation. Results: Ethosomal vesicles were spherical in shape and Zeta size, zeta potential, PDI (polydispersity index), % EE and in-vitro skin permeation of optimized formulation (F3) were found to be 114.7nm, -18.9mV, 0.492, 97.51±0.023%, and 79.88±0.013% respectively. AUU loaded ethosomal gel formulation was stable physicochemically and exhibited non-Newtonian behavior rheologically. Moreover, it significantly reduced skin erythema, melanin as well as sebum level and improved skin hydration and elasticity. Conclusion: A stable AUU based ethosomal gel formulation could be a better vehicle for phytoextracts than conventional formulations for cosmeceutical applications such as for skin rejuvenation and depigmentation etc.

scholarly journals Determining the Rate-Limiting Step for Light-Responsive Redox Regulation in Chloroplasts

Antioxidants ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 153 ◽  
Author(s):  
Keisuke Yoshida ◽  
Toru Hisabori
Keyword(s):  
Redox Regulation ◽  
Reducing Power ◽  
Rubisco Activase ◽  
Power Transfer ◽  
Target Proteins ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Thiol-based redox regulation ensures light-responsive control of chloroplast functions. Light-derived signal is transferred in the form of reducing power from the photosynthetic electron transport chain to several redox-sensitive target proteins. Two types of protein, ferredoxin-thioredoxin reductase (FTR) and thioredoxin (Trx), are well recognized as the mediators of reducing power. However, it remains unclear which step in a series of redox-relay reactions is the critical bottleneck for determining the rate of target protein reduction. To address this, the redox behaviors of FTR, Trx, and target proteins were extensively characterized in vitro and in vivo. The FTR/Trx redox cascade was reconstituted in vitro using recombinant proteins from Arabidopsis. On the basis of this assay, we found that the FTR catalytic subunit and f-type Trx are rapidly reduced after the drive of reducing power transfer, irrespective of the presence or absence of their downstream target proteins. By contrast, three target proteins, fructose 1,6-bisphosphatase (FBPase), sedoheptulose 1,7-bisphosphatase (SBPase), and Rubisco activase (RCA) showed different reduction patterns; in particular, SBPase was reduced at a low rate. The in vivo study using Arabidopsis plants showed that the Trx family is commonly and rapidly reduced upon high light irradiation, whereas FBPase, SBPase, and RCA are differentially and slowly reduced. Both of these biochemical and physiological findings suggest that reducing power transfer from Trx to its target proteins is a rate-limiting step for chloroplast redox regulation, conferring distinct light-responsive redox behaviors on each of the targets.

scholarly journals Evaluation of Antioxidant Properties ofPhaulopsis fascisepalaC.B.Cl. (Acanthaceae)

2009 ◽  
Vol 6 (2) ◽  
pp. 227-231 ◽  
Author(s):  
S. A. Adesegun ◽  
A. Fajana ◽  
C. I. Orabueze ◽  
H. A. B. Coker
Keyword(s):  
Ascorbic Acid ◽  
Leaf Extract ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Total Phenolic ◽  
Chelating Ability

The antioxidant activities of crude extract ofPhaulopsis fascisepalaleaf were evaluated and compared with α-tocopherol and BHT as synthetic antioxidants and ascorbic acid as natural-based antioxidant.In vitro, we studied its antioxidative activities, radical-scavenging effects, Fe2+-chelating ability and reducing power. The total phenolic content was determined and expressed in gallic acid equivalent. The extract showed variable activities in all of thesein vitrotests. The antioxidant effect ofP. fascisepalawas strongly dose dependent, increased with increasing leaf extract dose and then leveled off with further increase in extract dose. Compared to other antioxidants used in the study, α-Tocopherol, ascorbic acid and BHT,P. fascisepalaleaf extract showed less scavenging effect on α,α,-diphenyl-β-picrylhydrazyl (DPPH) radical and less reducing power on Fe3+/ferricyanide complex but better Fe2+-chelating ability. These results revealed thein vitroantioxidant activity ofP.fascisepala.Further investigations are necessary to verify these activitiesin vivo.

scholarly journals Phytochemical screening and evaluation of antioxidant capacities of Allium cepa, Allium sativum, and Monodora myristica using in vitro and in vivo models

2021 ◽  
Vol 1 (1) ◽  
pp. 41-52
Author(s):  
Chioma E. Irozuru Irozuru ◽  
Janet O. Olugbodi ◽  
Uche Okuu Arunsi ◽  
Olusola Ladeji
Keyword(s):  
Ascorbic Acid ◽  
Allium Cepa ◽  
Plant Extracts ◽  
Allium Sativum ◽  
Reducing Power ◽  
Aqueous Extracts ◽  
In Vivo Models ◽  
Monodora Myristica

Background: Allium cepa, Allium sativum, and Monodora myristica are commonly sourced food condiments in every household in Nigeria. In the present study, we investigated the phytochemical compositions, in vitro and in vivo antioxidant activity of these plants. Methods: The aqueous extracts from the A. cepa, A. sativum, and M. myristica were evaluated for phytochemical composition using standard protocols while the antioxidant activities were evaluated using the reducing power assay. Forty-five (45) Male Wistar rats (weighing 185±10 g) were divided into five groups (n=9) and were orally administered with 100 mg/kg BW each of A. sativum, M. myristica, A. cepa, and ascorbic acid while the control group received 0.5 mL/kg BW distilled water alone. Animals (n=3) from each group were sacrificed after the 20th, 25th, and 30th days of oral administration. The blood and tissue samples were collected for the analysis of biochemical parameters. Result: Our results revealed the presence of flavonoids, alkaloids, tannins, saponins, and terpenes in the plant extracts. A. sativum had the highest reducing power capacity followed by M. myristica and then A. cepa. The in vitro antioxidants activities demonstrated by the plant extracts were higher than that of ascorbic acid but less than butylated hydroxytoluene. In vivo antioxidant studies showed a marked increase (p<0.05) in the level of catalase with a concurrent decrease (p<0.05) in the levels of MDA and H2O2 in the liver and kidney of rats administered with aqueous extracts of the condiments compared to the normal control and ascorbic acid in the following order control < ascorbic acid < A. cepa < M. myristica < A. sativum. Conclusion: Based on these findings, we infer that the aqueous extracts of A. cepa, A. sativum, and M. myristica are rich in antioxidants and as a result could serve as promising novel functional foods and nutraceuticals

Bio-electrochemical production of hydrogen and electricity from organic waste

2021 ◽  
Author(s):  
Giorgia De Gioannis ◽  
Alessandro Dell'Era ◽  
Aldo Muntoni ◽  
Mauro Pasquali ◽  
Alessandra Polettini ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Electron Flow ◽  
Dark Fermentation ◽  
Electrochemical Process ◽  
Integrated System ◽  
Galvanic Cell ◽  
Hydrogen Yield ◽  
Cell Coupling ◽  
Production Of Hydrogen ◽  
Acid Metabolites

Abstract This study investigated the performance of a novel integrated bio-electrochemical system for synergistic hydrogen production from a process combining a dark fermentation reactor and a galvanic cell. The operating principle of the system is based on the electrochemical conversion of protons released upon dissociation of the acid metabolites of the biological process and is mediated by the electron flow from the galvanic cell, coupling biochemical and electrochemical hydrogen production. Accordingly, the galvanic compartment also generates electricity. Four different experimental setups were designed to provide a preliminary assessment of the integrated bio-electrochemical process and identify the optimal configuration for further tests. Subsequently, dark fermentation of cheese whey was implemented both in a stand-alone biochemical reactor and in the integrated bio-electrochemical process. The integrated system achieved a hydrogen yield in the range 75.5 – 78.8 N LH2/kg TOC, showing a 3 times improvement over the biochemical process.

Composition and Potential Health Benefits of Pomegranate: A Review

2019 ◽  
Vol 25 (16) ◽  
pp. 1817-1827 ◽  
Author(s):  
Vesna Vučić ◽  
Milkica Grabež ◽  
Armen Trchounian ◽  
Aleksandra Arsić
Keyword(s):  
Current Knowledge ◽  
Health Benefits ◽  
Punica Granatum ◽  
In Vivo Studies ◽  
Full Potential ◽  
Fruit Peel ◽  
Potential Health ◽  
Comprehensive Search

Background:: Pomegranate (Punica granatum L.) fruits are widely consumed and used as preventive and therapeutic agents since ancient times. Pomegranate is a rich source of a variety of phytochemicals, which are responsible for its strong antioxidative and anti-inflammatory potential. Objective:: The aim of this review is to provide an up-to-date overview of the current knowledge of chemical structure and potential health benefits of pomegranate. Method: : A comprehensive search of available literature. Results:: The review of the literature confirms that juice and extracts obtained from different parts of this plant, including fruit peel, seeds, and leaves exert health benefits in both in vitro and in vivo studies. The antidiabetic, antihypertensive, antimicrobial and anti-tumour effects of pomegranate fruit are of particular scientific and clinical interest. Conclusion:: Further investigations are required to clarify the mechanism of action of the bioactive ingredients and to reveal full potential of pomegranate as both preventive and therapeutic agent.

Hydrogen Evolution Catalyzed by Hydrogenase in Cultures of Cyanobacteria

1981 ◽  
Vol 36 (1-2) ◽  
pp. 87-92 ◽  
Author(s):  
Patrick C. Hallenbeck ◽  
Leon V. Kochian ◽  
John R. Benemann
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
High Frequency ◽  
Nitrogenase Activity ◽  
Inhibitory Effect ◽  
Hydrogenase Activity ◽  
Oxygen Inhibition ◽  
Oxygen Sensitive

Abstract Cultures of Anabaena cylindrica, grown on media containing 5 mᴍ NH4Cl (which represses heterocyst formation), evolved hydrogen after a period of dark incubation under an argon atmosphere. This hydrogen production was not due to nitrogenase activity, which was nearly undetectable, but was due to a hydrogenase. Cultures grown on media with tungsten substituted for molybdenum had a high frequency of heterocysts (15%) and inactive nitrogenase after nitrogen starvation. The hydrogenase activity of these cultures was three-fold greater than the activity of non-heterocystous cultures. The effects of oxygen inhibition on hydrogen evolution by hetero-cystous cultures suggest that two pools of hydrogenase activity exist - an oxygen sensitive hydrogen evolution in vegetative cells and a relatively oxygen-resistent hydrogen evolution in heterocysts. In either case, inhibition by oxygen was reversible. Light had an inhibitory effect on net hydrogen evolution. Hydrogen production in vitro was much higher than in vivo, indicating that in vivo hydrogenase activity is limited by endogenous reductant supply.

scholarly journals Antioxidant and Anti-inflammatory Activities of Cynaroside from Elsholtiza bodinieri

2018 ◽  
Vol 13 (11) ◽  
pp. 1934578X1801301 ◽  
Author(s):  
Ying Zou ◽  
Min Zhang ◽  
Tingrui Zhang ◽  
Junwen Wu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Radical Scavenging ◽  
Reducing Power ◽  
Total Content ◽  
Preparative Hplc ◽  
Dpph Radical ◽  
Anti Inflammatory ◽  
Flavonoid Fraction ◽  
Reducing Power Assay

The flavonoid fraction was obtained from Elsholtiza bodinieri Vaniot (EBV) by ethanol-reflux and liquid-liquid extraction. The total content of flavonoid was 179.55 mg/g, and the purity was 64.6%. Then cynaroside with the purity of 94% was isolated from the fraction by preparative HPLC and characterized by the combined usage of HPLC, ESI-MS, and NMR. The antioxidant activity of cynaroside was determined using 2 complementary methods, namely, 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power assay. The anti-inflammatory effect of cynaroside was investigated based on in-vitro and in-vivo experiment. The results showed that cynaroside from EBV scavenged DPPH radical and reduced Fe3+ to Fe2+ effectively, inhibited NO and ROS production in LPS-stimulated RAW264.7 cells and attenuated the inflammation in the mouse model significantly ( p < 0.01), which showed it to be a nutraceutical product in the food industry.

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