scholarly journals UVA and UVB Photoprotective Capabilities of Topical Formulations Containing Mycosporine-like Amino Acids (MAAs) through Different Biological Effective Protection Factors (BEPFs)

Marine Drugs ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 55 ◽  
Author(s):  
Francisca de la Coba ◽  
José Aguilera ◽  
Nathalie Korbee ◽  
María de Gálvez ◽  
Enrique Herrera-Ceballos ◽  
...  
Keyword(s):  
Amino Acids ◽  
In Vitro Tests ◽  
Antioxidant Compounds ◽  
Protection Factor ◽  
Effective Protection ◽  
Alkaline Conditions ◽  
Solar Uv ◽  
The Stability ◽  
Ph Range

The safety and stability of synthetic UV-filters and the procedures for evaluating the photoprotective capability of commercial sunscreens are under continuous review. The influence of pH and temperature stressors on the stability of certain Mycosporine-like amino acids (MAAs) isolated at high purity levels was examined. MAAs were highly stable at room temperature during 24 h at pH 4.5–8.5. At 50 °C, MAAs showed instability at pH 10.5 while at 85 °C, progressive disappearances were observed for MAAs through the studied pH range. In alkaline conditions, their degradation was much faster. Mycosporine-serinol and porphyra-334 (+shinorine) were the most stable MAAs under the conditions tested. They were included in four cosmetically stable topical sunscreens, of which the Sun Protection Factor (SPF) and other Biological Effective Protection Factors (BEPFs) were calculated. The formulation containing these MAAs showed similar SPF and UVB-BEPFs values as those of the reference sunscreen, composed of synthetic UV absorbing filters in similar percentages, while UVA-BEPFs values were slightly lower. Current in vitro data strongly suggest that MAAs, as natural and safe UV-absorbing and antioxidant compounds, have high potential for protection against the diverse harmful effects of solar UV radiation. In addition, novel complementary in vitro tests for evaluation of commercial sunscreens efficacy are proposed.

Simulation of sunscreen performance

2015 ◽  
Vol 87 (9-10) ◽  
pp. 937-951 ◽  
Author(s):  
Bernd Herzog ◽  
Uli Osterwalder
Keyword(s):  
Sun Protection ◽  
Simulation Algorithm ◽  
Uv Filters ◽  
Protection Factor ◽  
Stage Of Development ◽  
Screening Performance ◽  
Convenient Approach ◽  
Solar Uv ◽  
Harmful Effects

AbstractSunscreens are used to protect the human skin against harmful effects of solar UV radiation. The most important quantity characterizing sunscreen performance is the sun protection factor (SPF). At the stage of development of new sun protection formulations quick and inexpensive methods for estimation of the UV screening performance are highly desirable. The most convenient approach towards this goal is given by computational simulations. Models for the calculation of the SPF employ the same algorithm as used with in vitro SPF measurements, but replace the transmittance measurement by the calculation of the overall absorbance of the UV filters in an irregular sunscreen film. The simulations require a database with quantitative UV extinction spectra of the relevant UV filters as well as a mathematical description of the film irregularity. The simulation algorithm implies also the consideration of photodegradation properties of the UV filters in the sunscreen composition. Besides using such simulations for designing new sunscreen formulations, the calculations can also support the understanding of sunscreen performance in general.

scholarly journals Antioxidant Fucoidans Obtained from Tropical Seaweed Protect Pre-Osteoblastic Cells from Hydrogen Peroxide-Induced Damage

Marine Drugs ◽  
2019 ◽  
Vol 17 (9) ◽  
pp. 506 ◽  
Author(s):  
Gabriel Pereira Fidelis ◽  
Cynthia Haynara Ferreira Silva ◽  
Leonardo Thiago Duarte Barreto Nobre ◽  
Valquíria Pereira Medeiros ◽  
Hugo Alexandre Oliveira Rocha ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Bone Fragility ◽  
Sulfated Polysaccharides ◽  
In Vitro Tests ◽  
Antioxidant Compounds ◽  
Caspase 9 ◽  
Sod Activity ◽  
Alp Activity ◽  
Intracellular Ros

Some antioxidant compounds decrease the amount of intracellular reactive oxygen species (ROS) and consequently reduce the deleterious effects of ROS in osteoblasts. Thus, these compounds fight against osteoporosis. Brown seaweeds are a rich source of antioxidant fucose-containing sulfated polysaccharides (fucans and fucoidans). We obtained six fucoidans (FRFs)—F0.3, F0.5, F0.7, F1.0, F1.5, and F2.1—from Dictyota mertensii by proteolytic digestion followed by sequential acetone precipitation. Except for F0.3, all FRFs showed antioxidant activity in different in vitro tests. In pre- osteoblast-like cells (MC3T3-L1) exposed to H2O2-oxidative stress, caspase-3 and caspase-9 were activated, resulting in apoptosis of the cells. We also observed a decrease in superoxide dismutase (SOD) and alkaline phosphatase (ALP) activity. The antioxidant FRFs protected the cells from the oxidative damage caused by H2O2, decreasing intracellular ROS and caspase activation, and increasing SOD activity. The most effective protection against damage was provided by F0.7, F1.5, and F2.1. At 0.5 mg/mL, these FRFs also suppressed the H2O2-mediated inhibition of ALP activity. The data indicated that FRFs F0.7, F1.5, and F2.1 from D. mertensii were antioxidants that protected bone tissue from oxidative stress and could represent possible adjuvants for the treatment of bone fragility through counteracting oxidative phenomena.

scholarly journals DEVELOPMENT AND EVALUATION OF MUCOADHESIVE NANOGEL OF NEVIRAPINE FOR VAGINAL APPLICATION

2019 ◽  
pp. 144-149
Author(s):  
Sheikh Sofiur Rahman ◽  
ABDUL BAQUEE AHMED
Keyword(s):  
Hiv Infection ◽  
Ex Vivo ◽  
Vaginal Fluid ◽  
Content Uniformity ◽  
Vaginal Mucosa ◽  
Salting Out ◽  
Zero Order Kinetics ◽  
The Stability ◽  
Ph Range

Objectives: The main objective of this study was to develop and evaluate Nevirapine nanoparticle loaded mucoadhesive gel (NVP-Np mucoadhesive gel) for vaginal application for the treatment of HIV infection.  Methods: NVP loaded nanoparticles were prepared by salting out method followed by incorporation in different gel bases to produce NVP-Np mucoadhesive gel The prepared gels were evaluated for their physicochemical parameters, rheological characteristics, mucoadhesion, in-vitro drug release and ex-vivo permeation of drug across porcine vaginal mucosa.  Results: The result of FT-IR and DSC study confirmed the absence of incompatibility of NVP with excipients used in the formulations. The particle size of the prepared NVP-Np was found to be 243.8 ± 3.15 nm, a polydispersity index (PI) of 0.787± 0.002 and zeta potential value -17.12 mV, which revealed the stability of nanoparticles. All the formulations showed good homogeneity, spreadability, physical appearance and content uniformity. The pH of the mucoadhesive gel formulations was in the range of 3.70 ± 0.03 to 4.56 ± 0.02, which lies in the normal pH range of the vaginal fluid.  The cumulative amounts permeated at 6 h were 832.23 ± 63.45 μg/cm2 , 592.13 ± 82.55 μg/cm2 and 941.32 ± 81.10 μg/cm2 from F1(1% Chitosan), F2(1% Carbopol 974P) and F3 (1% HPMC K100M )  respectively. A linear relationship [r2 > 0.9 (0.97 n 0.99)] was observed between the percentage cumulative amount permeated and time, indicating zero order kinetics. Conclusion: In conclusion, NVP-Np mucoadhesive gel was prepared successfully using salting out followed by a homogenization technique for vaginal application of NVP for the prophylaxis of HIV infection.

scholarly journals Complexation of Th(IV) and Eu(III) by α-isosaccharinic acid under alkaline conditions

2001 ◽  
Vol 89 (6) ◽  
Author(s):  
K. Vercammen ◽  
M.A. Glaus ◽  
Luc R. Van Loon
Keyword(s):  
Stability Constants ◽  
Data Sets ◽  
Complexation Reaction ◽  
Sorption Data ◽  
Alkaline Conditions ◽  
The Stability ◽  
Ph Range ◽  
Complexation Reactions ◽  
Best Fit ◽  
Isosaccharinic Acid

The complexation of Th(IV) and Eu(III) by α-isosaccharinic acid (ISA) has been studied in the pH range from 10.7 to 13.3 by batch sorption experiments, and the influence of Ca on the complexation was investigated. Sixteen data sets – each determined at variable ISA concentrations – are used to determine the stoichiometry of the complexation reactions and the stability constants. Based on best-fit analysis of the sorption data, it is postulated that 1:1 Th:ISA complexes are formed in the absence of Ca according to the complexation reaction: Th+ISA↔(ThISA)

scholarly journals Expression of a Heterologous Glutamate Dehydrogenase Gene inLactococcus lactis Highly Improves the Conversion of Amino Acids to Aroma Compounds

2000 ◽  
Vol 66 (4) ◽  
pp. 1354-1359 ◽  
Author(s):  
Liesbeth Rijnen ◽  
Pascal Courtin ◽  
Jean-Claude Gripon ◽  
Mireille Yvon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamate Dehydrogenase ◽  
Aroma Compounds ◽  
In Vitro Tests ◽  
Limiting Factor ◽  
Keto Acid ◽  
Cheese Curd ◽  
The Impact

ABSTRACT The first step of amino acid degradation in lactococci is a transamination, which requires an α-keto acid as the amino group acceptor. We have previously shown that the level of available α-keto acid in semihard cheese is the first limiting factor for conversion of amino acids to aroma compounds, since aroma formation is greatly enhanced by adding α-ketoglutarate to cheese curd. In this study we introduced a heterologous catabolic glutamate dehydrogenase (GDH) gene into Lactococcus lactis so that this organism could produce α-ketoglutarate from glutamate, which is present at high levels in cheese. Then we evaluated the impact of GDH activity on amino acid conversion in in vitro tests and in a cheese model by using radiolabeled amino acids as tracers. The GDH-producing lactococcal strain degraded amino acids without added α-ketoglutarate to the same extent that the wild-type strain degraded amino acids with added α-ketoglutarate. Interestingly, the GDH-producing lactococcal strain produced a higher proportion of carboxylic acids, which are major aroma compounds. Our results demonstrated that a GDH-producing lactococcal strain could be used instead of adding α-ketoglutarate to improve aroma development in cheese.

Review: Role of tubal environment in preimplantation embryogenesis: application to co-culture assays

Zygote ◽  
2010 ◽  
Vol 19 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Pierre Guérin ◽  
Yves Ménézo
Keyword(s):  
Amino Acids ◽  
Embryo Culture ◽  
Metabolic Flux ◽  
Cultured Cells ◽  
Culture Media ◽  
Culture Conditions ◽  
Antioxidant Compounds ◽  
Beneficial Effects ◽  
Stage Embryo

SummaryThe culture of early preimplantation stage embryo is still delicate and the metabolic pathways of embryos are not completely understood. Embryo needs are evolutionary during the preimplantation development, consequently it is difficult to meet embryo needs in vitro. Culture conditions have to respect several physical and chemical equilibria: such as redox potential, pH, osmotic pressure, metabolic flux of energetic compounds, endogenous pools of amino acids and transcripts, etc. Embryo culture media are generally supplemented with amino acids, glucose, other energetic metabolites and antioxidant compounds, vitamin, and growth factors etc. Furthermore autocrine and paracrine regulation of embryo development probably exist. In fact embryo culture conditions have to be as non-toxic as possible. Various types of co-culture systems have been devised to overcome these problems. Complex interrelations exist between embryos and co-cultured cells. The beneficial effects of co-cultured cells may be due to continuous modifications of the culture medium, i.e. the elimination of toxic compounds and/or the supply of embryotrophic factors.

scholarly journals Preliminary Study of the Potential Photoprotective Effect of Organogel-Based Lipstick Formulations: Texture Analysis, Rheological, Thermal and Sensory Properties

2021 ◽  
Author(s):  
Cloé L. Esposito ◽  
Plamen Kirilov
Keyword(s):  
Texture Analysis ◽  
Stability Study ◽  
Protection Factor ◽  
Protective Properties ◽  
Uv Protective Properties ◽  
The Stability ◽  
Low Molecular Weight Organogelators ◽  
Harmful Effects ◽  
Unique Chemical

With the increase in occupation-specific risks of lip cancer associated with solar radiation, there is a need for developing photoprotective lipsticks to protect skin against harmful effects of UV radiation. Considering the unique chemical and physical properties of low-molecular-weight organogelators (LMOGs), the present study intended to assess the UV protective properties of LMOGs-based lipstick formulations. In this study, dibenzylidene-D-sorbitol (DBS) and 12-hydroxystearic acid (12-HSA) were used to formulate lipsticks : L1 (1% DBS), L2 (10% 12-HSA), L3 (1.5% DBS) and L4 (control, no LMOGs). The lipstick formulations were tested for in vitro sun protection factors (SPF), UVA protection factor (UVA-PF), thermal, mechanical and texture analyses. Lipsticks with LMOGs exhibited higher UVA-PF and SPF, and more particularly 12-HSA-based lipstick. Results showed also the viscoelastic and heat-resistant properties of LMOGs and their effect of increasing pay-off values. In general, texture analysis indicating that 12-HSA-based lipstick was significantly harder to bend compared to control, while other formulations became softer and easier to bend throughout the stability study. Finally, sensorial and instrumental analyses permitted to classify lipsticks into two groups. This work suggests the potential use of LMOGs as a structuring agent for lipsticks paving the way towards more photoprotective and sustainable-derived alternatives.

scholarly journals Crystal structure of HECT domain of UBE3C E3 ligase and its ubiquitination activity

2020 ◽  
Vol 477 (5) ◽  
pp. 905-923 ◽  
Author(s):  
Sunil Singh ◽  
J. Sivaraman
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Enzymatic Activity ◽  
Cancer Metastasis ◽  
E3 Ligase ◽  
The Other ◽  
Hect Domain ◽  
Loop Region ◽  
The Stability

The HECT family of E3 ubiquitin ligase is divided into three subfamilies: the NEDD4, the HERC, and the ‘other’. Previous studies have mostly targeted members of the NEDD4 subfamily for structural and functional analysis. The UBE3C E3 ligase is a member of the ‘other’ subfamily HECT and influences several crucial cellular processes, including innate immunity, proteasome processivity, and cancer metastasis. Here, we report the crystal structure of the HECT domain of UBE3C (amino acids (aa) 744–1083) with an additional fifty N-terminal amino acids (aa 693–743) at 2.7 Å, along with multiple in vitro ubiquitination assays to understand its enzymatic activity. The UBE3C HECT domain forms an open, L-shaped, bilobed conformation, having a large N-lobe and a small C-lobe. We show that the N-terminal region (aa 693–743) preceding the UBE3C HECT domain as well as a loop region (aa 758–762) in the N-lobe of the HECT domain affect the stability and activity of UBE3C HECT domain. Moreover, we identified Lys903 in the UBE3C HECT domain as a major site of autoubiquitination. The deletion of the last three amino acids at the C-terminal completely abrogated UBE3C activity while mutations of Gln961 and Ser1049 residues in the HECT domain substantially decreased its autoubiquitination activity. We demonstrate that these region/residues are involved in the E2–E3 transthiolation process and affect the UBE3C mediated autoubiquitination. Collectively, our study identified key residues crucial for UBE3C enzymatic activity, and it may assist in the development of suitable inhibitors to regulate its activity in multiple cancers.

scholarly journals In vitro Protein Synthesis and Measurement of the Stability of Messenger RNA in the Blue-green Alga, Anabaena variabilis

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 47-58 ◽  
Author(s):  
C. K. Leach ◽  
N. G. Carr
Keyword(s):  
Amino Acids ◽  
Green Alga ◽  
Messenger Rna ◽  
Antibiotic Sensitivity ◽  
Anabaena Variabilis ◽  
Blue Green Alga ◽  
Peptide Formation ◽  
A Cell ◽  
The Stability

A cell-free preparation of the blue-green alga, Anabaena variabilis, that incorporates 14C-labelled amino acids into protein has been prepared and characterized. The activation of amino acids to amino acid transfer RNAs was characterized, and assembly of these into peptides has been described with respect to cofactor requirements and antibiotic sensitivity. The properties of these systems and the effect of antibiotics on them are similar to those of bacteria. Both natural and synthetic messenger RNA were effective in peptide formation. The kinetics of incorporation of [14C]uracil into RNA has been examined and the stability of labelled RNA from A. variabilis measured by radioactivity loss and by its role in directing peptide synthesis. The half-life of messenger RNA from this organism is approximately 12 min, and as such is comparable to that of bacteria when based upon the mean generation time of the respective organisms.

scholarly journals Influence of Amino Acids on the Mobility of Iodide in Hydrocalumite

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 836
Author(s):  
Mengmeng Wang ◽  
Hirofumi Akamatsu ◽  
Keiko Sasaki
Keyword(s):  
Amino Acids ◽  
Ion Exchange ◽  
Interlayer Spacing ◽  
Organic Substances ◽  
Cement System ◽  
Anionic Species ◽  
Alkaline Conditions ◽  
Living Organisms ◽  
The Stability ◽  
Formation Energies

In the cement system, hydrocalumite is a candidate adsorbent for low-level 129I anionic species. However, the stability of hydrocalumite after immobilizing I− is unclear when they are exposed to pedosphere characterized by organic substances derived from living organisms. In the present work, five amino acids were selected as simplified models of natural organic substances under alkaline conditions. L-cysteine (H2Cys) and L-aspartic acid (H2Asp) accelerated the release of I− from I-hydrocalumite through ion-exchange. Ion-exchange of Cys2− with I− in I-hydrocalumite was faster than Asp2−, and the interlayer spacing (d003) of Cys-hydrocalumite was smaller than that of Asp-hydrocalumite. DFT simulations not only supported the above results but also predicted that there was a positive correlation between the formation energies and interlayer spacings of amino acids intercalated hydrocalumite, depending on the configurations. Moreover, in the DFT predictions, the interaction between amino acids and metallic hydroxide layers was responsible for the formation of hydrogen bonds and Ca-O chemical bonds between the -COO− groups and [Ca2Al(OH)6]+. The other three amino acids did not show intercalation through ion-exchange. The stability of I-hydrocalumite is influenced differently by coexisting amino acids, depending on the ionic sizes, charge numbers, and hydrophilicity, which cause the second contamination.

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