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•Pure lignin (ca. 98 % pure) is isolated from elephant grass leaves.•Elephant grass lignin has high concentration of phenolic groups (3.85 mmol g−1).•Stable (pH 5–11 and ionic ...strength below 0.01) lignin nanoparticles are assembled.•Lignin nanoparticles show high antioxidant activity as compared to other lignins.•Tinted sunscreen lotions are obtained with lignin nanoparticles.
Finding renewable and green resources for nanomaterial preparation is a compelling topic concerning the sustainability in nanotechnological applications. In particular, lignin-based nanoparticles are pivotal for unlocking the use of lignin in value added products. In this paper, we isolated pure lignin (ca. 98 % of purity) from elephant grass (Pennisetum purpureum) using two simple extractions with diluted acid and alkali solutions and prepared lignin and lignin acetate nanoparticles dispersed in water-basis by anti-solvent addition. Elephant grass in natura contains ca. 25 % of lignin, which could be converted into lignin nanoparticles with a 37 % yield. Spherical lignin and lignin acetate nanoparticles were revealed by electron microscopies (TEM and FESEM) and proved to be stable in a wide pH range (5–11) and ionic strength lower than 0.01. Lignin nanoparticles showed higher antioxidant activity (RSI of ca. 82) as compared to lignin in solution and to the commercial antioxidants (BHT and BHA). These nanoparticles were successfully incorporated in a neutral cream, resulting in a tinted sunscreen formulation with both ultraviolet and visible absorption. Altogether, we present here an effective method to isolate pure lignin from a non-food biomass and to prepare stable and highly antioxidant lignin nanoparticles that can be applied in dermocosmetics and are intrinsically non-toxic to the environment.
The oxidative stress mechanism in the body involves the balance between increased ROS and decreased antioxidant agents. ROS can damage DNA, proteins, and lipids, leading to pathology and impaired ...insulin secretion by dysregulation of several genes expression. High concentrations of ROS are often followed by a low activity of antioxidants from endogenous sources. As a result, exogenous antioxidants are required to neutralize ROS. As reported, medicinal plants, which have had various traditional applications, contain large amounts of secondary metabolites, proven to be exogenous antioxidant agents. Jamu, a traditional medicine, also known as an alternative medication, can be widely and easily found in traditional markets. Antidiabetic herbal products are among the most popular of jamu. Antidiabetic mechanism has a strong relationship with antioxidant roles in many biological systems. The aim of this research was to figure out the potential antioxidant activity of antidiabetic herbal products. Eight antidiabetic jamu samples were analyzed for their antioxidant activity by measuring the DPPH radical scavenging activity, phosphomolybdenum antioxidant activity, and FRAP, as well as for their total phenolic and flavonoid contents. Good linearity was a general finding for the quantitative analysis, with an average correlation coefficient of 0.999 for the standards. The highest total flavonoid content found was 8.66 ± 0.11 mgQE/g, and the highest total phenolic content was 22.66 ± 0.15 mgGAE/g. With regard to antioxidant activity, all of the samples demonstrated weak DPPH radical scavenging activity, while phosphomolybdenum antioxidant activity and FRAP were the highest at 48.58 ± 0.45 mgQE/g extract and 226.98 ± 0.19 mgQE/g extract, respectively. These results indicated that the claimed antidiabetic herbal products could be prepared as exogenous antioxidant sources, irrespective of being with or without antioxidant activity, for diabetes treatment.
Banana (
Musa acuminata Colla AAA) peel extracts obtained in this work had a high capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH
) and 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid ...(ABTS
+
) free radicals, and they were also good lipid peroxidation inhibitors. Acetone:water extracts were considerably more effective (compared with methanol, ethanol, acetone, water, methanol:water or ethanol:water) at inhibiting the peroxidation of lipids in the β-carotene/linoleic acid system or scavenging free radicals. However, aqueous extracts had a high capacity to protect lipids from oxidation in the thiobarbituric acid reactive substances (TBARS) test, as well as in the β-carotene bleaching assay. In addition, acetone:water most efficiently extracted all extractable components (54
±
4%), phenolic compounds (3.3
±
0.8%), and anthocyanin compounds (434
±
97
μg cyanidin 3-glucoside equivalents/100
g freeze-dried banana peel). Banana peel contained large amounts of dopamine and L-dopa, catecholamines with a significant antioxidant activity. However, ascorbic acid, tocopherols or phytosterols were not detected in the different extracts. The antioxidant activity of banana peel extracts from different cultivars was similar. However, the impact of extraction time or temperature should be studied in greater depth.
Water deficit stress is one major environmental constraint having a devastating impact on crop productivity. Improving plant tolerance to drought is imperative to ensure food security. Drought stress ...during maize seedling establishment stage lowers the seedling survival rate and increases post pollination embryo abortion rate. Thus, an experiment was carried out as factorial in randomized complete design with three replicates to evaluate the tolerance mechanism of five local maize cultivars at Department of Life Sciences (Botany), Manipur University, Manipur during February to April, 2022. The maize seeds were allowed to germinate under control environment conditions: 14h light/10h dark, 25±2oC temperature and 60% relative humidity using a growth chamber (Tanco PLT-149 Plant Growth Chamber). At seven days after emergence, different concentrations of PEG-6000 were used to impose water deficit stress to maize seedlings. It was observed that drought stress substantially inhibited growth and development across all cultivars. Relative water content (RWC) as well as chlorophyll pigment concentration showed gradual decline under different drought stress levels with cultivar M002 being the least affected. Drought stress also triggered significant augmentation of osmolytes and antioxidant activity with maximum accumulation in cultivar M002. Overall findings from this study indicate that cultivar M002 possess promising drought tolerance characteristics and can perform successfully in water scarce regions.
Estimates of the activity of antioxidants in the literature often appear inconsistent. In the specific case of the DPPH∙ test, the diversity of measurements may arise from variations in the protocols ...followed. This paper proposes an unbiased method which models the reduction mechanism. This method is applied to the reduction of DPPH∙ by ferulic acid. A scheme with eight coupled reactions is proposed and has been validated on different solvents and using a wide range of DPPH ̇, ferulic acid, and 5,5′-diferulic acid concentrations, and verified using data from the literature on ferulic acid activity. This modeling approach permits a correction to the bias of the 8th reaction (spontaneous reduction of DPPH ̇), because of its sensitivity to solvent, which in most cases is not taken into account. The best experimental strategy to determine the Efficient Concentration of ferulic acid to reduce 20% (EC20) and 50% (EC50) of DPPH∙ is then detailed in terms of initial DPPH∙ concentrations and the duration of the experiment.
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•We have established a stoichiokinetic model of DPPH∙ reduction by ferulic acid.•Different concentrations, solvents and data have validated the 8-reaction model.•Solvents can impact the spontaneous DPPH∙ reduction more than the ferulic acid action.•The EC50 of ferulic acid is dependent on the low initial concentrations of DPPH ̇.•The DPPH∙ concentration and duration of experiments have been optimized for EC50.
Four fractions, namely, rice bran, rice husk, brown rice and milled rice of a Thai rice variety (Khao Dawk Mali 105), collected from three different growth sites, were analysed to determine phenolic ...acid composition, γ-oryzanol and tocopherols content and their antioxidant capacity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH
) radical scavenging and ferric reducing ability power (FRAP) assays. The bran and husk fractions showed higher values of antioxidant activity based on the DPPH
and FRAP assays, compared to the other fractions. In addition, the bran fraction had the highest γ-oryzanol and tocopherols content. On the other hand, the husk fraction showed a greater phenolic acids concentration than the other fractions. The three major phenolic acids found in all fractions, despite different growth sites, were ferulic, vanillic and
p-coumaric acids. Ferulic acid was most evident in the bran, whereas vanillic and
p-coumaric acids were mostly found in the husk. Significant differences (
p
<
0.05) in the antioxidant capacities of each fraction depended on the growth sites and antioxidant components. We propose that variation in phenolic acid content could be affected by the growth sites. This study demonstrates that rice bran and husk can be considered as valuable sources of bioactive components with high antioxidant properties.
•Melatonin treatment confers chilling tolerance in pomegranate fruit.•Melatonin treatment attenuates H2O2 accumulation by enhancing SOD, CAT, APX and GR activity.•Melatonin treatment maintains ...membrane integrity by hindering PLD and LOX activity.•Pomegranate fruit treated with melatonin exhibits higher PAL activity and lower PPO activity.•Melatonin treatment promotes phenols accumulation resulting superior DPPH scavenging capacity.
In this study, the mechanism hired by melatonin treatments (0, 1, 10, 100 and 1000 μM) for conferring chilling tolerance in pomegranate fruit during storage at 4 °C for 120 days was explored. Melatonin treatment at 100 μM meaningfully conferred chilling tolerance in pomegranate fruit manifesting by lower husk browning accompanying by higher membrane integrity representing by lower electrolyte leakage and malondialdehyde (MDA) accumulation. Higher membrane integrity in pomegranate fruit treated with melatonin may arise from lower H2O2 accumulation owing to higher reactive oxygen species (ROS) scavenging enzymes catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) activity. In addition to higher ROS scavenging enzymes activity, higher membrane integrity in pomegranate fruit treated with melatonin may ascribe to lower membrane degrading enzymes phospholipase D (PLD) and lipoxygenase (LOX) activity. Also, higher phenols accumulation giving rise to higher DPPH scavenging capacity arising from higher phenylalanine ammonia-lyase (PAL) enzyme activity concomitant with lower polyphenol oxidase (PPO) enzyme activity may be vital for conferring chilling tolerance in pomegranate fruit by exogenous melatonin applying. Accordingly, exogenous melatonin applying serves as a safe beneficial strategy for conferring chilling tolerance in pomegranate fruit during cold storage.
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