scholarly journals Brown Seaweed Defensive Chemicals: A Structure-activity Relationship Approach for the Marine Environment

2009 ◽  
Vol 4 (2) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Éverson Miguel Bianco ◽  
Valéria Laneuville Teixeira ◽  
Renato Crespo Pereira ◽  
Alessandra Mendonça Teles de Souza ◽  
Pedro Nucci ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Pathogenic Bacteria ◽  
Brown Seaweed ◽  
Structure Activity Relationship ◽  
Structural Features ◽  
Activity Relationship ◽  
Chemical Structures ◽  
Structure Activity ◽  
Minimum Requirements ◽  
New Perspective

The literature describes several diterpenes from brown seaweeds that act as defensive chemicals against natural enemies, such as competitors, epiphytes, pathogenic bacteria and herbivores. A structure-activity relationship is here presented using a new molecular modeling approach to identify structural and chemical features important to the defensive profile of four structurally related diterpenes (three dolastanes and one seco-dolastane) from Canistrocarpus cervicornis against the feeding process of the omnivorous sea urchin Lytechinus variegatus. Our experimental data revealed the herbivory inhibitory profile (HIE) for three of these evaluated compounds with (4R, 7R, 14S)-4α, 7α-diacetoxy-14-hydroxydolast-1(15),8-diene presenting the highest effect (HIE = 70%). Interestingly, the molecular modeling results infer that this biological activity seems to be related to several different structural features, including HOMO distribution, the molecular structure conformation, and the fulfillment of minimum requirements regarding molecular weight. These results reinforce the hypothesis about the intricate biological mechanism of these molecules due to the complexity of their chemical structures. Our work may help in the understanding of these defensive mechanisms and point to a new perspective of ecological and/or evolutionary evaluation in this area.

Structure-activity relationship of the pro- and anticoagulant effects of Fucus vesiculosus fucoidan

2014 ◽  
Vol 111 (03) ◽  
pp. 429-437 ◽  
Author(s):  
Cong Jiang ◽  
Sabine Knappe ◽  
Sabrina Reutterer ◽  
Christina Szabo ◽  
Michael Dockal ◽  
...  
Keyword(s):  
Charge Density ◽  
Biological Activities ◽  
Brown Seaweed ◽  
Structure Activity Relationship ◽  
Structural Features ◽  
Fucus Vesiculosus ◽  
Factor Ix ◽  
Activity Relationship ◽  
Structure Activity ◽  
The Impact

SummaryFucoidan is a highly complex sulfated polysaccharide commonly extracted from brown seaweed. In addition to their many biological activities, fucoidans have recently been demonstrated to inhibit or increase coagulation at different concentration ranges. Their structural features, i.e. molecular weight (Mw), Mw distribution, degree of sulfation, monosaccharide composition, and different linkages, are known to affect these activities. Therefore, structure-activity relationship (SAR) analysis of fucoidan is crucial for its potential use as a procoagulant. In this study, Fucus vesiculosus (F.v.) fucoidan was fractionated by charge and size as well as over- and desulfated to different degrees to yield preparations with various structural properties. The fractions’ pro- and anticoagulant activities were assessed by calibrated automated thrombography (CAT) and activated partial thromboplastin time (aPTT) assays. Binding to and inhibition of the anticoagulant protein tissue factor pathway inhibitor (TFPI) and the ability to activate coagulation via the contact pathway were also investigated. This paper discusses the impact of charge density, size, and sugar composition on fucoidan’s pro- and anticoagulant activities. Fucoidan requires a minimal charge density of 0.5 sulfates per sugar unit and a size of 70 sugar units to demonstrate desired procoagulant activities for improvement of haemostasis in factor VIII/factor IX-deficient plasma.

scholarly journals Prediction of Terpenoid Toxicity Based on a Quantitative Structure–Activity Relationship Model

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 628 ◽  
Author(s):  
Rosa Perestrelo ◽  
Catarina Silva ◽  
Miguel X. Fernandes ◽  
José S. Câmara
Keyword(s):  
Vibrio Fischeri ◽  
Quantitative Structure Activity Relationship ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Partial Charge ◽  
Quantitative Structure ◽  
Chemical Structures ◽  
Structure Activity ◽  
Qsar Models ◽  
Toxicity Level

Terpenoids, including monoterpenoids (C10), norisoprenoids (C13), and sesquiterpenoids (C15), constitute a large group of plant-derived naturally occurring secondary metabolites with highly diverse chemical structures. A quantitative structure–activity relationship (QSAR) model to predict terpenoid toxicity and to evaluate the influence of their chemical structures was developed in this study by assessing in real time the toxicity of 27 terpenoid standards using the Gram-negative bioluminescent Vibrio fischeri. Under the test conditions, at a concentration of 1 µM, the terpenoids showed a toxicity level lower than 5%, with the exception of geraniol, citral, (S)-citronellal, geranic acid, (±)-α-terpinyl acetate, and geranyl acetone. Moreover, the standards tested displayed a toxicity level higher than 30% at concentrations of 50–100 µM, with the exception of (+)-valencene, eucalyptol, (+)-borneol, guaiazulene, β-caryophellene, and linalool oxide. Regarding the functional group, terpenoid toxicity was observed in the following order: alcohol > aldehyde ~ ketone > ester > hydrocarbons. The CODESSA software was employed to develop QSAR models based on the correlation of terpenoid toxicity and a pool of descriptors related to each chemical structure. The QSAR models, based on t-test values, showed that terpenoid toxicity was mainly attributed to geometric (e.g., asphericity) and electronic (e.g., maximum partial charge for a carbon (C) atom (Zefirov’s partial charge (PC)) descriptors. Statistically, the most significant overall correlation was the four-parameter equation with a training coefficient and test coefficient correlation higher than 0.810 and 0.535, respectively, and a square coefficient of cross-validation (Q2) higher than 0.689. According to the obtained data, the QSAR models are suitable and rapid tools to predict terpenoid toxicity in a diversity of food products.

Bioactivities of Natural Catalpol Derivatives

2019 ◽  
Vol 26 (33) ◽  
pp. 6149-6173 ◽  
Author(s):  
Liu-Qiang Zhang ◽  
Kai-Xian Chen ◽  
Yi-Ming Li
Keyword(s):  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Inhibitory Potency ◽  
Pharmacological Activities ◽  
Chemical Structures ◽  
Naturally Occurring ◽  
Structure Activity ◽  
Extensive Coverage ◽  
Relationship Of

Catalpol, a famous molecule of iridoids, possesses extensive pharmacological activities. Our studies found that compounds with low-polarity substituents at the 6-O position of catalpol exhibited higher NF-κB inhibitory potency than catalpol. However, catalpol derivatives are not much focused. Here this review provides extensive coverage of naturally occurring catalpol derivatives discovered from 1888 until 2018. It covers their distribution, chemotaxonomic significance, chemical structures, and bioactivities from more than 200 peer-reviewed articles, and highlights the structure-activity relationship of catalpol derivatives.

Chemistry and Structure-Activity Relationships of Herbicide Safeners

1991 ◽  
Vol 46 (9-10) ◽  
pp. 798-804 ◽  
Author(s):  
Tamás Kőmíves ◽  
Kriton K. Hatzios
Keyword(s):  
Research And Development ◽  
Chemical Properties ◽  
Structure Activity Relationship ◽  
Close Similarity ◽  
Activity Relationship ◽  
Rapid Progress ◽  
Commercial Success ◽  
Chemical Structures ◽  
Structure Activity ◽  
Agricultural Use

Abstract The discovery and commercial success of safeners against thiolcarbamate herbicide injury to corn has stimulated a rapid progress and opened new possibilities for further research and development in the last decade. Compounds with new chemistry, increased efficacy, and a broader selectivity spectrum were synthesized and developed for agricultural use. Structure-activity relationship studies helped to optimize their chemical properties and to understand their biological modes of action. Several examples indicate close similarity between chemical structures possessing herbicidal and safener properties. In some cases this differentiation may be marginal, as shown in crops pretreated with low herbicide doses leading to safening effects. In other examples, however, structural optima for safening and herbicidal efficacy can be clearly differentiated.

Synthesis of Antimicrobial N-Phthaloyl-alanyl-derived Amidophosphates and Triazoles

2009 ◽  
Vol 64 (9) ◽  
pp. 1057-1064 ◽  
Author(s):  
Wafaa M. Abdou ◽  
Neven A. Ganoub ◽  
Eman Sabry
Keyword(s):  
Benzoyl Peroxide ◽  
Structure Activity Relationship ◽  
Structural Features ◽  
Activity Relationship ◽  
Lead Compounds ◽  
Structure Activity ◽  
Trialkyl Phosphites

N-Phthaloyl-alanylazide reacts smoothly with trialkyl phosphites producing the corresponding α- aminophosphates. With dialkyl hydrogenphosphonates in the presence of benzoyl peroxide, amidophosphates were the isolated products whereas the oxoaziridin-1-yl-phosphonic diamide was preferentially provided from the reaction of the azide with tris(dimethylamino)phosphine. The azide was also allowed to react with α-keto-, α-ethoxycarbonyl- and α-cyanomethylenetriphenylphosphorane to give the corresponding linear disubstituted 1,2,3-triazoles. Screening results of antibiotic potency for the products were discussed in terms of structure-activity relationship (SAR), and an attempt was made to define the structural features for lead compounds.

Improving the Nicotinic Pharmacophore with a Series of (Isoxazole)methylene-1-azacyclic Compounds:  Synthesis, Structure−Activity Relationship, and Molecular Modeling

1999 ◽  
Vol 42 (24) ◽  
pp. 4970-4980 ◽  
Author(s):  
Janne E. Tønder ◽  
John Bondo Hansen ◽  
Mikael Begtrup ◽  
Ingrid Pettersson ◽  
Karin Rimvall ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structure Activity
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