Phytotoxic evaluation of Phragmites australis: an investigation of aqueous extracts of different organs

2012 ◽  
Vol 63 (9) ◽  
pp. 777 ◽  
Author(s):  
Md N. Uddin ◽  
Domenico Caridi ◽  
Randall W. Robinson
Keyword(s):  
Phragmites Australis ◽  
Invasive Plants ◽  
Aerobic Condition ◽  
Water Soluble ◽  
Aqueous Extracts ◽  
Soluble Phenolics ◽  
Leaf Leachate ◽  
Allelopathic Interference ◽  
The Stability ◽  
Germination Bioassays

Phragmites australis is one of the most widespread and invasive plants on earth. Allelopathic interference has been considered as a possible way associated with its invasiveness in wetlands. A series of ecologically realistic experiments was conducted to explore allelochemical phytotoxicity of Phragmites. Germination bioassays using aqueous extracts of different organs (leaf, stem, root and rhizome) of Phragmites were tested with model seeds (Lactuca sativa and Raphanus sativus) and associated plant species (Juncus pallidus and Rumex conglomeratus). These studies showed that leaf and rhizome extracts exhibited strong inhibition on germination, biometric and physiological parameters (all P ≤ 0.001). Dose–response studies confirmed LC50 (4.68% and 11.25%) of Lactuca for leaf and rhizome extracts respectively. Root growth of Juncus and Rumex was inhibited by 75% and 30%, respectively, in leaf leachate-incorporated soil. Chlorophyll content and maximum quantum yield (Fv/Fm) were significantly reduced with leaf and rhizome leachates. The stability and quantity of water-soluble phenolics in anaerobic versus aerobic condition may influence phytotoxic effects to other species. Phragmites organs can be ranked in order of allelopathic potentiality as follows: leaf > rhizome > root > stem. The present study highlighted the potential impacts of allelochemicals on plant recruitment in wetlands invaded by Phragmites.

Allelopathic interference of chickweed, Stellaria media with seedling growth of wheat (Triticum aestivum)

1998 ◽  
Vol 76 (7) ◽  
pp. 1317-1321 ◽  
Author(s):  
Inderjit ◽  
KMM Dakshini
Keyword(s):  
Seedling Growth ◽  
Water Soluble ◽  
Growth Stages ◽  
Weed Species ◽  
Natural Conditions ◽  
Stellaria Media ◽  
Current Season ◽  
Soluble Phenolics ◽  
Allelopathic Interference ◽  
Annual Weeds

The question whether or not annual weeds are allelopathic under field conditions is important in assessing the interference potential of annual weed species. Research was conducted to investigate the probable involvement of allelopathy in the interference potential of chickweed, Stellaria media, a polycarpic winter annual weed. Chickweed maintains heterogeneous populations represented by different age-classes under natural conditions. Results indicate that both young and mature growth stages of chickweed contribute water-soluble phenolics to the soil. Soil amended with matured chickweed had a higher phenolic content than weed-infested soils. Both weed-infested and weed-amended soil affect the seedling growth of wheat. Chickweed could be allelopathic also to a crop of the current season under natural conditions, as it contributes water-soluble compounds to its associated soil.Key words: allelopathy, competition, chickweed, phenolics, weed, wheat.

Is phytotoxicity of Phragmites australis residue influenced by decomposition condition, time and density?

2014 ◽  
Vol 65 (6) ◽  
pp. 505 ◽  
Author(s):  
Md. N. Uddin ◽  
Randall W. Robinson ◽  
Domenic Caridi ◽  
Md. A. Y. Harun
Keyword(s):  
Phragmites Australis ◽  
Wetland Management ◽  
Water Soluble ◽  
Anaerobic Conditions ◽  
Soil Extracts ◽  
Soluble Phenolics ◽  
Physicochemical Variables ◽  
Residue Decomposition ◽  
Germination And Growth ◽  
Over Time

Phragmites australis is an invasive wetland plant and allelopathy appears to contribute to its invasiveness. We studied dynamics of physicochemical characteristics and phytotoxicity through residue decomposition of Phragmites with and without soil under different conditions and density over time. Physicochemical variables (water-soluble phenolics, dissolved organic carbon, specific ultraviolet absorbance, pH, electrical conductivity, osmotic potential and some anions, namely PO43–, Cl–, NO2–, NO3– and SO42–) of extracts were more consistent and showed normal range in aerobic rather than anaerobic conditions. ‘Residue alone’ and ‘residue with soil’ extracts exhibited significant inhibition on germination and growth of Poa labillardierei and Lactuca sativa initially but reduced over time in aerobic conditions whereas the inhibition increased sharply and remained almost stable in anaerobic conditions (P ≤ 0.001). Regression analyses showed that water-soluble phenolics were a significant predictor of the inhibitory effects on germination and growth of tested species compared with other variables in the extracts. Long-term decomposed residues exhibited significant effects on germination and growth of Melaleuca ericifolia (P ≤ 0.01) depending on residue density in soil. The results demonstrated that decomposition condition and soil incorporation coupled with residue density may play a crucial role over time in dynamics of physicochemical variables and associated phytotoxicity. The study contributes to understanding of the ecological consequences of phytotoxins in residue decomposition, partially explaining the invasion process of Phragmites in wetlands and thereby improving wetland management.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

scholarly journals Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Laura Brelle ◽  
Estelle Renard ◽  
Valerie Langlois
Keyword(s):  
Gallic Acid ◽  
Tannic Acid ◽  
Water Soluble ◽  
Gel Formation ◽  
Ene Reaction ◽  
Inorganic Cations ◽  
Medium Chain Length ◽  
Physically Crosslinked ◽  
The Stability ◽  
Derivatives Of

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

TOXICITY OF SMOKE FROM SPOROPHORES OF THE INDIAN PAINT FUNGUS AND WOOD FROM WESTERN HEMLOCK TO YELLOWFEVER MOSQUITOES

1987 ◽  
Vol 119 (12) ◽  
pp. 1109-1115
Author(s):  
W.P.L. Osborn ◽  
J.H. Borden
Keyword(s):  
British Columbia ◽  
Aedes Aegypti ◽  
Combustion Products ◽  
Tsuga Heterophylla ◽  
Water Soluble ◽  
Western Hemlock ◽  
Aqueous Extracts ◽  
Smoke Water

AbstractTo mitigate the effects of mosquitoes, settlers in the Revelstoke area of British Columbia reportedly burned the sporophores of the Indian paint fungus, Echinodontium tinctorium (Ell. & Ev.) Ell. & Ev., a pathogen of western hemlock, Tsuga heterophylla (Raf.) Sarg., and true firs, Abies spp. Larval and adult yellowfever mosquitoes, Aedes aegypti (L.), were exposed to aqueous extracts of smoke (smoke-waters) from E. tinctorium sporophores, and from western hemlock sapwood and heartwood. Smoke-waters were of approximately equal toxicity to larvae. Fungus smoke-water, but not sapwood or heartwood smoke-waters, lost 50% of its potency in 5 months. Vapors from fungus smoke-water were significantly more toxic to adult mosquitoes than those from sapwood or heartwood. Thus smoke from E. tinctorium sporophores and T. heterophylla wood apparently contain different water-soluble combustion products toxic to A. aegypti.

Development of Curcumin-Loaded Polymeric Mixed Micelle for Skin Moisturizing Antioxidant Formulation

2021 ◽  
Vol 901 ◽  
pp. 98-103
Author(s):  
Sunee Channarong ◽  
Parapat Sobharaksha ◽  
Chanchai Sardseangjun ◽  
Panipak Vasvid
Keyword(s):  
Mixed Micelle ◽  
Polymeric Micelles ◽  
Entrapment Efficiency ◽  
Water Soluble ◽  
Poloxamer 407 ◽  
Average Particle ◽  
Yellow Color ◽  
Stability Data ◽  
Hydrogenated Castor Oil ◽  
The Stability

Abstract The aim of this study was to fabricate curcumin-loaded polymeric mixed micelle which was a new nanocarrier of therpeutic agent for skin uses. Curcumin was extracted from dried turmeric rhizomes using ethanol and recrystallized. The purity of curcumin was 79±3.6 %w/w. Six curcumin-loaded polymeric micelles (PM1-PM6) were prepared by simple dissolution method using poloxamer 407 (5% and 10%) as a main core structure. PEG-40 hydrogenated castor oil (PEG-40HCO) was incorporated at two percentages (2.5% and 5.0%) to study the effect on the nanoparticle characteristics. The average particle sizes of PM1-PM6 were in the range of 33.3±6.6 nm to 171.3±52.8 nm. The entrapment efficiency and the loading capacity of curcumin were in the range of 47.45%-77.35% and 0.048%w/w-0.078%w/w, respectively. When PEG-40HCO was incorporated in to the polymeric micelles, the particle size decreased and the entrapment efficiency increased. Thus, PM4 and PM5 were selected for further study. Moisturizing antioxidant creams containing 0.005%w/w of curcumin loaded in PM4, PM5 and curcumin simply dissolved in propylene glycol (PG) were formulated. The resulted formulations showed good spreadability and good characteristics. After being subjected to accelerated test, all of the formulations remained with characteristic color, pH and showed no phase separation. The stability data showed that the moisturizing antioxidant creams were stable for the whole 3 months after storage at accelerated temperature (45°C/75%RH). The study demonstrated that polymeric mixed micelle spontaneously encapsulated a poorly water-soluble curcumin and increased the solubility up to 250 folds. The developed moisturizing cream containing 0.005%w/w of curcumin resulted a greenish-yellow color preparation. It had tolerable physicochemical properties based on curcumin content, pH and viscosity under the harsh condition. The cream also had satisfactory antioxidant activity, which can be regarded as an effective and acceptable therapeutic or skincare products for topical uses.

672 An Investigation of Antibiotic Loading and Release in Acid-precipitated Keratin Proteins to Treat Topical Burn Infections

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S192-S193
Author(s):  
Marc A Thompson ◽  
Robert J Christy
Keyword(s):  
Proteolytic Enzymes ◽  
Diglycidyl Ether ◽  
Water Soluble ◽  
Bacterial Colony ◽  
Freeze Dried ◽  
Antibiotic Compounds ◽  
Water Ph ◽  
Stable Product ◽  
Antibiotic Release ◽  
The Stability

Abstract Introduction Human-hair derived keratin (KOS) protein has been selected in this investigation for its ability to bind antibiotic compounds and provide sustained release while withstanding harsh proteolytic environments such as inflamed, damaged tissue. The need to control local flora has been recognized as an imperative for wound healing, as recovery is significantly hampered by infection. This study investigates the synthesis of KOS-based particulate matter, developed using acid-precipitation, to load and release the water-soluble antibiotic ciprofloxacin (CIP). We hypothesize that ionically bound CIP release is tied to the degradation of KOS, therefore, bacterial metabolism, which produces proteolytic enzymes, will trigger CIP release thereby creating a novel self-extinguishing delivery system for contaminated skin wounds. Methods Ciprofloxacin hydrochloride was solubilized in deionized water (pH 5.3) under constant stirring. Freeze-dried KOS powder was added for an ultimately 5% w/v and 0.8% w/v solution of KOS and CIP, respectively. To improve the stability of KOS a water-soluble diglycidyl ether crosslinker was added to solutions and stirred for 24 hours. CIP-loaded protein was precipitated out by a hydrochloric acid induced pH reduction. Samples were collected and frozen at -20 °C prior to lyophilization, thus forming the stable product. Degradation of KOS and commensurate release of CIP were measured using a bicinchoninic acid (BCA) assay and fluorescent measurements of hydrated material supernatant. The reduction of bacterial colonies was validated by a broth inhibition assay whereby CIP-loaded KOS or unloaded KOS controls where hydrated in bacterial-laden broth cultures of Pseudomonas aeruginosa or Methicillin-resistant Staphylococcus aureus. Cultures were sampled at 24, 48, or 72 hours and plated to quantify colony-forming units. Results The presence of CIP in the KOS protein was confirmed and release rates follow similar patterns to that of KOS degradation. CIP-loaded proteins significantly reduce bacterial colony presence in concentrated inoculant solutions up to 72 hours. Conclusions CIP release does appear to coincide with KOS degradation, which is bolstered in the presence of infectious levels of bacteria. Ongoing studies aim to observe more robust models of infection and more controlled antibiotic release.

scholarly journals SYNTHESIS OF NEW SUBSTITUTED PROCAINE HYDROCHLORIDE COMPOUNDS AND THEIR USE IN SPECTROPHOTOMETRIC DETERMINATION OF TETRACYCLINE HYDROCHLORIDE THROUGH DIAZOTIZATION-COUPLING REACTIONS

2021 ◽  
Vol 18 (39) ◽  
pp. 14-32
Author(s):  
Hind Sadiq Al-WARD ◽  
Mouayed Qassssim AL-ABACHI ◽  
Mohammed Rifaat AHMED
Keyword(s):  
Stability Constant ◽  
Thermodynamic Parameters ◽  
Coupling Reaction ◽  
Water Soluble ◽  
Procaine Hydrochloride ◽  
Effect Of Temperature ◽  
Basic Medium ◽  
Fast Method ◽  
The Stability

Background: Tetracycline is one of the most important antibiotics. It is used to treat many different bacterial infections. It is often used in treating severe acne, or sexually transmitted diseases such as syphilis, gonorrhea, or chlamydia. In some cases, tetracycline is used when penicillin or another antibiotic cannot be used to treat serious infections such as the ones caused by Bacillus anthracis, Listeria, Clostridium, Actinomyces. Aim: synthesized a new novel reagent used to determine TCH spectrophotometrically by using diazonium and coupling reaction. Methods: Four new substituted procaine derivatives were prepared by simple organic methods using aniline derivatives. A spectrophotometric approach was established for the micro-determination of TCH. The stoichiometry was investigated using mole ratio and continuous variation methods, and the stability constant was also estimated. The ΔG, ΔH, and ΔS were determined as thermodynamic parameters for evaluating the effect of temperature on the reaction. Results: Substituted procaine derivatives were prepared, and o-hydroxy procaine seems to be the best reagent used to determine TCH by diazotization and coupling reaction. The result was a yellow water-soluble dye with a maximum absorbance of 380 nm. The reaction conditions were studied and optimized. Beers law was obeyed over a concentration range (2.5–50) μg.mL-1 for TCH. The molar absorptivity was (14.4669.103) L.mol-1.cm-1, and the detection limit was (0.5052) μg.mL-1. The stoichiometry of the formed product was found 1:1 (o-hydroxyprocaine: TCH). The stability constant indicated that the product formed was stable, and the thermodynamic parameters showed that the diazonium salt reaction was preferred to occur at a low temperature. Conclusions: a simple, accurate, and fast method was developed to determine TCH in pure form and pharmaceuticals by coupling the TCH with a newly synthesized procaine derivative reagent (o-hydroxy procaine) in a basic medium.

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