scholarly journals Synthesis of Biobased Phloretin Analogues: An Access to Antioxidant and Anti-Tyrosinase Compounds for Cosmetic Applications

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 512
Author(s):  
Laurène Minsat ◽  
Cédric Peyrot ◽  
Fanny Brunissen ◽  
Jean-Hugues Renault ◽  
Florent Allais
Keyword(s):  
Natural Products ◽  
Consumer Demand ◽  
Radical Scavenging ◽  
Green Process ◽  
Direct Extraction ◽  
Low Concentration ◽  
Cosmetic Formulations ◽  
Valuable Compounds ◽  
The Stability

The current cosmetic and nutraceutical markets are characterized by a strong consumer demand for a return to natural products that are less harmful to both the consumers and the environment than current petrosourced products. Phloretin, a natural dihydrochalcone (DHC) found in apple, has been widely studied for many years and identified as a strong antioxidant and anti-tyrosinase ingredient for cosmetic formulations. Its low concentration in apples does not allow it to be obtained by direct extraction from biomass in large quantities to meet market volumes and prices. Moreover, its remarkable structure prevents its synthesis through a green process. To overcome these issues, the synthesis of phloretin analogs appears as an alternative to access valuable compounds that are potentially more active than phloretin itself. Under such considerations, 12 chalcones (CHs) and 12 dihydrochalcones (DHCs) were synthesized through a green Claisen–Schmidt condensation using bio-based reagents. In order to evaluate the potential of these molecules, radical scavenging DPPH and anti-tyrosinase tests have been conducted. Moreover, the UV filtering properties and the stability of these analogs towards UV-radiations have been evaluated. Some molecules showed competitive antioxidant and anti-tyrosinase activities regarding phloretin. Two compounds in particular showed EC50 lower than phloretin, one chalcone and one dihydrochalcone.

scholarly journals STUDIES ON THE FUNCTION OF INTRACELLULAR RIBONUCLEASES

1966 ◽  
Vol 29 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Takeshi Utsunomiya ◽  
Jay S. Roth
Keyword(s):  
Natural Products ◽  
Sodium Chloride ◽  
Rat Liver ◽  
Messenger Rna ◽  
Rnase Activity ◽  
Optimum Ph ◽  
Normal Rat ◽  
Pancreatic Rnase ◽  
The Stability ◽  
Normal Constituent

The RNase activity and properties of ribosome and polysome preparations from normal rat liver and some hepatomas have been examined. Polysome and ribosome preparations from the Novikoff, McCoy MDAB, and Dunning hepatomas had considerably higher specific RNase activity than corresponding preparations from normal rat liver, Novikoff ascites, or Morris 5123 hepatomas. The optimum pH of the RNase was approximately 8.5 for all samples tested, and the samples showed no evidence of latent RNase activity when treated with 3 M sodium chloride, EDTA, urea, or p-chloromercuribenzenesulfonic acid. The RNase activity appeared to be associated principally with breakdown products and/or subunits smaller than 80S. In the presence of Mg++ ions, subunits could reaggregate to form monomer ribosomes indistinguishable from the natural products, but some of the reassociated ribosomes could contain RNase activity which had been bound to the smaller particles. Similar results were obtained with spermine. In the hepatomas, evidence was obtained for the preexistence of considerable amounts of the smaller, RNase-containing subunits in the cell. When a small amount of crystalline bovine pancreatic RNase was added to partly dissociated ribosomes, the RNase was found only in association with the smaller subunits, and little or no enzyme was taken up by ribosomes or polysomes. The results have led to the conclusion that RNase is not a normal constituent of the ribosome or polysome, but that RNase may become associated with these particulates if dissociation and reassociation take place. Some implications of these findings for the stability of messenger RNA and for the mechanism of its breakdown are discussed.

scholarly journals Computational Studies of 4-Formylpyridinethiosemicarbazone and Structural and Biological Studies of Its Ni(II) and Cu(II) Complexes

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mydhili P. Sripathi ◽  
Sireesha Berely ◽  
Chittireddy Venkata Ramana Reddy
Keyword(s):  
Elemental Analysis ◽  
Radical Scavenging ◽  
Molar Conductance ◽  
Computational Studies ◽  
Hydrolytic Cleavage ◽  
Bacterial Strains ◽  
Intercalative Mode ◽  
Biological Studies ◽  
Calf Thymus ◽  
The Stability

To understand the stability, chelation behaviour, and biological activity of 4-Formylpyridinethiosemicarbazone (H4FPT), it is important to recognize its interactive geometry. Hence, computational studies on geometrically optimized structures of thione and thiol forms of H4FPT were performed. Binary metal complexes of the ligand, H4FPT (L) with the Ni(II) and Cu(II) metal ions (M), were synthesized and characterized by various spectroanalytical techniques as elemental analysis, molar conductance, magnetic susceptibility measurements, LC-MS, TGA, IR, UV-Visible, ESR, and powder XRD. Elemental analysis, LC-MS, and TGA studies indicate 1:2 (ML2) composition for mononuclear Ni(II) complex and 1:1 (ML) composition for dinuclear Cu(II) complex. Electronic absorption titrations, fluorescence quenching studies, and viscosity measurements suggest intercalative mode of binding of the complexes with calf thymus DNA (CT-DNA). These complexes also promote hydrolytic cleavage of plasmid pBR322. The ligand (H4FPT) and its complexes showed moderate-to-good activity against Gram-positive and Gram-negative bacterial strains. The DPPH radical scavenging studies showed antioxidant nature of both complexes.

scholarly journals Emphasized Mechanistic Antimicrobial Study of Biofunctionalized Silver Nanoparticles on Model Proteus mirabilis

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Asra Parveen ◽  
Manjunath S. Yalagatti ◽  
Venkataraman Abbaraju ◽  
Raghunandan Deshpande
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Proteus Mirabilis ◽  
Reducing Sugars ◽  
Radical Scavenging ◽  
Human Pathogens ◽  
Antimicrobial Study ◽  
Synthetic Procedure ◽  
Dpph Method ◽  
The Stability

Antimicrobial study of biofunctionalized silver nanoparticles has been done with the emphasis on its mechanism on both gram positive and negative bacteria. The biofunctionalized silver nanoparticles are employed considering their importance in green chemistry with respect to easy synthesis, usefulness, and economic synthetic procedure involved. The stability of these nanoparticles was determined by zeta potential analyzer. The probable mechanism of antibacterial activity was performed on Proteus mirabilis by field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDAX) study which does not show the presence of silver. The free radicals generated by silver nanoparticles were responsible for lethal antibacterial activity by rupturing the cell surface which causes improper nutrient and signal supply. Free radical scavenging efficacy of silver nanoparticles was confirmed by 1,1-Diphenyl-2-picrylhydrazyl (DPPH) method. AgNP enhanced the membrane leakage of reducing sugars by destroying the proteins existing on the cell wall. These nanoparticles are found to be toxic against human pathogens and are highly effective on Staphylococcus aureus. The effect of silver nanoparticles is concentration dependent and independent of the type of strains used.

scholarly journals Effect of Extraction Conditions on the Antioxidant Activity of Olive Wood Extracts

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Mercedes Pérez-Bonilla ◽  
Sofía Salido ◽  
Adolfo Sánchez ◽  
Teris A. van Beek ◽  
Joaquín Altarejos
Keyword(s):  
Geographical Origin ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Olive Tree ◽  
Extraction Yield ◽  
Scavenging Activity ◽  
Direct Extraction ◽  
Ethanolic Extracts ◽  
Wood Extracts ◽  
Main Components

An investigation to optimize the extraction yield and the radical scavenging activity from the agricultural by-product olive tree wood (Olea europaeaL., cultivar Picual) using six different extraction protocols was carried out. Four olive wood samples from different geographical origin, and harvesting time have been used for comparison purposes. Among the fifty olive wood extracts obtained in this study, the most active ones were those prepared with ethyl acetate, either through direct extraction or by successive liquid-liquid partitioning procedures, the main components being the secoiridoids oleuropein and ligustroside. An acid hydrolysis pretreatment of olive wood samples before extractions did not improve the results. In the course of this study, two compounds were isolated from the ethanolic extracts of olive wood collected during the olives’ harvesting season and identified as (7′′R)-7′′-ethoxyoleuropein (1) and (7′′S)-7′′-ethoxyoleuropein (2).

scholarly journals Spectral Characteristic, Storage Stability and Antioxidant Properties of Anthocyanin Extracts from Flowers of Butterfly Pea (Clitoria Ternatea L.)

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7000
Author(s):  
Xueying Fu ◽  
Qiang Wu ◽  
Jian Wang ◽  
Yanli Chen ◽  
Guopeng Zhu ◽  
...  
Keyword(s):  
Food Processing ◽  
Storage Stability ◽  
Ph Value ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Nutritional Values ◽  
Clitoria Ternatea ◽  
Alkaline Conditions ◽  
Butterfly Pea ◽  
The Stability

Anthocyanins from flowers of the butterfly pea (Clitoria ternatea L.) are promising edible blue food colorants. Food processing often faces extreme pHs and temperatures, which greatly affects the color and nutritional values of anthocyanins. This study explored the color, spectra, storage stability, and antioxidant properties of C. ternatea anthocyanin extract (CTAE) at different pHs. The color and absorption spectra of CTAEs at a pH of 0.5–13 were shown, with their underlying structures analyzed. Then, the storage stability of CTAEs were explored under a combination of pHs and temperatures. The stability of CTAE declines with the increase in temperature, and it can be stored stably for months at 4 °C. CTAEs also bear much resistance to acidic and alkaline conditions but exhibit higher thermal stability at pH 7 (blue) than at pH 0.5 (magenta) or pH 10 (blue-green), which is a great advantage in food making. Antioxidant abilities for flower extracts from the butterfly pea were high at pH 4–7, as assessed by DPPH free radical scavenging assays, and decreased sharply when the pH value exceeded 7. The above results provide a theoretical basis for the application of butterfly pea flowers and imply their great prospect in the food industry.

scholarly journals Development, characterization and stability of microemulsionated formulations of bacaba, Oenocarpus bacaba oil

2019 ◽  
Vol 49 (3) ◽  
pp. 246-255
Author(s):  
Maycon de Paula Ribeiro TORRES ◽  
Rhuan Vínicius de Freitas ESPRENDOR ◽  
Solange Maria BONALDO ◽  
Elton Brito RIBEIRO ◽  
Dênia Mendes de Sousa VALLADÃO
Keyword(s):  
Antioxidant Activity ◽  
Natural Products ◽  
Droplet Diameter ◽  
Radical Scavenging ◽  
Industrial Applications ◽  
Research Field ◽  
Hydrodynamic Diameter ◽  
Amazon Forest ◽  
Formulation Development ◽  
Rheological Characterization

ABSTRACT Advances in nanotechnology, combined with the use of natural products, represent a promissing research field. Brazil is a country of a rich biodiversity, especially in the Amazon forest. Fruits commonly used by local communities, such as bacaba (Oenocarpus bacaba), are potentially important for prospection of industrial applications of natural products. In nanotechnology, microemulsions stand out for providing a modified release to conveyed substances. This work aimed to develop microemulsionated formulations of bacaba oil, characterize them and evaluate their stability. We determined the HLB (hydrophile-lipophilic balance) of bacaba oil for formulation development. Six formulations were selected from pseudoternary diagrams, which indicated the proportions of surfactants, aqueous phase and bacaba oil. The viability of these formulations was evaluated through stability tests. We provided the rheological characterization of the formulations, evaluated their potential antioxidant activity through the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method, and determined the hydrodynamic diameter of the droplets. The microemulsions were stable throughout the test period. Droplet diameter was below 200 nm, and the microemulsions were characterized as newtonian fluids, presenting an increase in antioxidant activity when compared with the diluted oil. Our results confirm the potential of bacaba oil in microemulsionated formulation as a suitable carrier for active compounds.

scholarly journals Enhancement of Chemical Stability and Dermal Delivery of Cordyceps militaris Extracts by Nanoemulsion

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1565 ◽  
Author(s):  
Pachabadee Marsup ◽  
Kankanit Yeerong ◽  
Waranya Neimkhum ◽  
Jakkapan Sirithunyalug ◽  
Songyot Anuchapreeda ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Chemical Stability ◽  
Radical Scavenging Activity ◽  
Skin Irritation ◽  
Radical Scavenging ◽  
Water Extract ◽  
Cordyceps Militaris ◽  
Alpha Tocopherol ◽  
Dermal Delivery ◽  
The Stability

This study aimed to develop nanoemulsions for enhancing chemical stability and dermal delivery of Cordyceps militaris extracts. C. militaris was extracted by maceration and infusion. The extracts were investigated for cordycepin, phenolic, and flavonoid content. The antioxidant activity was investigated by in vitro spectrophotometric methods. The irritation profile was investigated by hen’s egg-chorioallantoic membrane test. Nanoemulsions were developed using high-pressure homogenizer. C. militaris extract was incorporated into the nanoemulsion and investigated for safety, release profile, permeation, and skin retention. The results demonstrated that water extract (CW) contained the significantly highest content of cordycepin, phenolics, and flavonoids, which were responsible for antioxidant activity. CW was the most potent antioxidant. CW possessed comparable 2,2′-diphenyl-1-picrylhydrazyl radical scavenging activity and lipid peroxidation inhibition to l-ascorbic acid (96.9 ± 3.1%) and alpha-tocopherol (87.2 ± 1.0%). Consequently, ten mg/mL of CW was incorporated into nanoemulsions composing of sugar squalene, Tween® 85, and deionized water. Nanoemulsion, which had the smallest internal droplet size (157.1 ± 2.6 nm), enhanced the stability of CW, had no cytotoxicity effect and no skin irritation, released the most CW (0.9 ± 0.0% w/w after 24 h), and delivered the highest CW into the skin layer (33.5 ± 0.7% w/w). Therefore, nanoemulsion was suggested for enhancing the stability and dermal delivery of CW.

scholarly journals Effect of Nanocrystallization of Anthocyanins Extracted from Two Types of Red-Fleshed Apple Varieties on Its Stability and Antioxidant Activity

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3366 ◽  
Author(s):  
Jihua Xu ◽  
Xinxin Li ◽  
Shifeng Liu ◽  
Peilei Zhao ◽  
Heqiang Huo ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Corn Starch ◽  
Uv Light ◽  
Radical Scavenging ◽  
Malus Sieversii ◽  
Total Anthocyanins ◽  
High Antioxidant Activity ◽  
Starch Nanoparticles ◽  
The Stability

Red-fleshed apple (Malus sieversii f. neidzwetzkyana (Dieck) Langenf) has attracted more and more attention due to its enriched anthocyanins and high antioxidant activity. In this study we extracted total anthocyanins and phenols from two types of red-fleshed apples—Xinjing No.4 (XJ4) and Red Laiyang (RL)—to study the stability and antioxidant activity of anthocyanins after encapsulation onto Corn Starch Nanoparticles (CSNPs). The results indicated the anthocyanins and total phenol levels of XJ4 were 2.96 and 2.25 times higher than those of RL respectively. The anthocyanin concentration and loading time had a significant effect on CSNPs encapsulation, and XJ4 anthocyanins always showed significantly higher loading capacity than RL. After encapsulation, the morphology of RL-CSNPs and XJ4-CSNPs was still spherical with a smooth surface as CSNPs, but the particle size increased compared to CSNPs especially for RL-CSNPs. Different stress treatments including UV light, pH, temperature, and salinity suggested that XJ4-CSNPs exhibited consistently higher stability than RL-CSNPs. A significantly enhanced free radical scavenging rate under stress conditions was observed, and XJ4-CSNPs had stronger antioxidant activity than RL-CSNPs. Furthermore, XJ4-CSNPs exhibited a slower released rate than RL-CSNPs in simulated gastric (pH 2.0) and intestinal (pH 7.0) environments. Our research suggests that nanocrystallization of anthocyanins is an effective method to keep the anthocyanin ingredients intact and active while maintaining a slow release rate. Compared to RL, encapsulation of XJ4 anthocyanins has more advantages, which might be caused by the significant differences in the metabolites of XJ4. These findings give an insight into understanding the role of nanocrystallization using CSNPs in enhancing the antioxidant ability of anthocyanins from different types of red-fleshed apples, and provide theoretical foundations for red-fleshed apple anthocyanin application.

scholarly journals Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 669 ◽  
Author(s):  
Anastasia Detsi ◽  
Eleni Kavetsou ◽  
Ioanna Kostopoulou ◽  
Ioanna Pitterou ◽  
Antonella Rozaria Nefeli Pontillo ◽  
...  
Keyword(s):  
Natural Products ◽  
Review Article ◽  
Modified Chitosan ◽  
The Past ◽  
Natural Extracts ◽  
Naturally Occurring ◽  
Natural Polysaccharide ◽  
Low Toxicity ◽  
Valuable Compounds ◽  
Chitosan Biopolymer

Chitosan is a cationic natural polysaccharide, which has emerged as an increasingly interesting biomaterialover the past few years. It constitutes a novel perspective in drug delivery systems and nanocarriers’ formulations due to its beneficial properties, including biocompatibility, biodegradability and low toxicity. The potentiality of chemical or enzymatic modifications of the biopolymer, as well as its complementary use with other polymers, further attract the scientific community, offering improved and combined properties in the final materials. As a result, chitosan has been extensively used as a matrix for the encapsulation of several valuable compounds. In this review article, the advantageous character of chitosan as a matrix for nanosystemsis presented, focusing on the encapsulation of natural products. A five-year literature review is attempted covering the use of chitosan and modified chitosan as matrices and coatings for the encapsulation of natural extracts, essential oils or pure naturally occurring bioactive compounds are discussed.

scholarly journals Re-evaluation of ABTS•+ Assay for Total Antioxidant Capacity of Natural Products

2015 ◽  
Vol 10 (12) ◽  
pp. 1934578X1501001 ◽  
Author(s):  
Jian-Wei Dong ◽  
Le Cai ◽  
Yun Xing ◽  
Jing Yu ◽  
Zhong-Tao Ding
Keyword(s):  
Natural Products ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reaction Times ◽  
Universal Method ◽  
Stable Free Radical ◽  
Abts Assay ◽  
Total Antioxidant

2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS•+) is a stable free radical frequently used for estimating the total antioxidant capacity (TAC) of natural products. The existing methods for ABTS•+ radical-scavenging activity assays are diverse in pre-diluting solvents and reaction time, which lead to errors in the TAC estimations. To develop an effective and universal method for estimating the ABTS•+ capacity accurately and reasonably, five pre-dilution solvents [methanol, ethanol, phosphate buffer (Na2HPO4-NaH2PO4, 200 mM, pH = 7.4), PBS buffer (Na2HPO4-NaH2PO4-NaCl, 200 mM, pH = 7.4), and distilled water] and different reaction times were investigated in ABTS•+ assays of five typical antioxidants. The results showed that the solvent effects were very significant. When using different pre-diluting solvents, different detection wavelengths should be selected. ABTS-+ assay could be measured within 2–10 min to obtain a rough result, which was mostly 6 min in the literature. However, full and accurate evaluation of antioxidant reactivity rather than capacity requires recording ABTS•+ loss continuously during the whole reaction period. The present study makes a recommendation for estimating the ABTS•+ capacity accurately and reasonably.

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