Journal of the Chilean Chemical Society

ANTIMICROBIAL AND SOD-LIKE ACTIVITIES OF N,N′-BIS(FERROCENYLMETHYLENE)ETHYLENEDIAMINE SCHIFF BASE AND IT’S METAL COMPLEXES

2021-09-15T21:04:45+00:00

The synthesized N,N′-bis(ferrocenylmethylene)ethylenediamine Schiff base and it’s metal complexes were screened in vitro for antimicrobial activity against two Gram-positive (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 7064),four Gram-negative (Escherichia coli ATCC 25922, Citrobacter koseri DBCC 01, Entorebacter aeruginosa ATCC 13048,Salmonella typhimurium DBCC 02) and antifungal activity against a Candida albicans. MIC values of the compounds ranged from 27 to 533 µg/mL. Compound (5) showed very strong activity against S. aureus with the best MIC (27 µg/mL). The lowest MIC for C. albicans was obtained 107 µg/mL. The superoxide dismutase activity of Schiff base and it’s metal complexes has been measured and discussed. SOD-like activities of bis ferrocenyl Schiff base ligand metal complexes were investigated using NBT. While only the Cu (II) complex showed SOD-like (40 μm IC₅₀) activity, the SOD-like activity value was not determined in the other complex and ligand.

POTENTIAL OF CURATELLA AMARICANA L. AGAINST SARS-COV2: BIOAVAILABILITY, MOLECULAR SIMILARITY AND MOLECULAR DOCKING BETWEEN SECONDARY METABOLITES AND PROTEASE TYPE 3-CHYMOTRYPSIN (3CLPRO)

2021-09-15T21:04:46+00:00

We report the bioavailability analysis for six secondary metabolites with antiviral, antioxidant and antitumor activity reported, from Curatella amaricana L. Additionally, the molecular similarity analysis of each metabolite is presented and compared with Lopinavir, Ritonavir, Darunavir, Cobicistat and Nelfinavir, which actually are in the third phase for the production of a new vaccine for SARS-Cov2. The mode of interaction through molecular docking between each structure and the zone of action for protease type 3-chymotrypsin (3CLpro) also is presented. The molecular geometry for structures were optimized at semiempirical PM6 level. The bioavailability and molecular docking calculations were performed using the algorithms incorporated in chemoinformatic servers and AutoDock Vina. The results show that the structures studied lead a moderated permeability through the cell membrane, by complying with Lipinski's "rule of 5”. Molecular similarity was evaluated by averaging geometric parameters (3D-Shape) and electrostatic potential (ESP). The results show that the most secondary metabolites would have a similar mode of action as the Lopinavir, with average similarity between 0.65 and 0.73. This last idea is reinforced by the results for molecular docking with the 3CLpro active site, highlighting the interaction of the molecules studied with the amino acid residues: His-41, Phe-140, Gly-143, Ser-144, Cys-145, His-163, Glu-166 and His-172, with an range interaction-free energy between -7.2 kcal/mol and -9.2 Kcal/mol, highlighting Quercetin 3-O-Alpha-L-rhamnoside with improve affinity energy than Lopinavir.

COMPARATIVE REMOVAL OF METHYLENE BLUE FROM AQUEOUS SOLUTION USING DIFFERENT ADSORBENTS

2021-09-15T21:04:46+00:00

A comparative study for the adsorption of Methylene blue onto different prepared adsorbents was investigated. First, a comparative study was performed with different parameters between orange peels, orange peels activated with phosphoric acid, orange peels activated encapsulating in alginate and orange peels activated encapsulating in magnetic alginate. It can be concluded that the magnetic alginate composite beads were the best adsorbent. Then the isotherms, kinetics and regeneration studies for the removal of Methylene blue were studied onto magnetic alginate composite beads. The adsorption of Methylene blue on magnetic alginate composite beads was applied to isotherm models showed that the interaction of Methylene blue with magnetic alginate composite beads surface is localized monolayer adsorption. The kinetic process flow a pseudo-second-order kinetic. Finally, the removal efficiencies were maintained using HCl solution as desorbing agent after five cycles of adsorption-desorption.

EFFECT OF GREEN SYNTHESIZED SILVER NANOPARTICLES ON CARNOSIC ACID CONTENT AND PHYSIO-BIOCHEMICAL PROPERTIES OF ROSMARINUS OFFICINALIS L.

2021-09-15T21:04:46+00:00

In biosynthesis of metal nanoparticles, it is possible to replace the old chemical synthesis methods with new environment-friendly procedures. In this study, AgNP was synthesized using extracts of Rosmarinus officinalis L. leaves, and then its effect on biochemical characters, antioxidant enzymes activity, and finally carnosic acid content was studied with its various concentrations. UV–visible spectroscopy was utilized to identify the formation of synthesized AgNP. Synthesized AgNP was confirmed the absorption maxima at 500 nm wavelength. Synthesized AgNP were measured using SEM and showed 21 nm at size and spherical shape. Application of various concentrations of synthesized AgNP demonstrated the concentration dependency so that, in concentration of 40 and 60 mM of synthesized AgNP, dry and fresh weight increased. Application of synthesized AgNP at 40 mM resulted in increase of chlorophyll amount which caused more activity in anti-oxidant enzymes and also biomass accumulation such as soluble carbohydrate and flavonoid. After treatment of synthesized AgNP at 40 mM concentration, HPLC demonstrated an increase in carnosic acid. Here, small nanoparticles revealed increased in secondary metabolites. Synthesized nanoparticles can also be utilized in order to produce natural products and plants with faster growth rates.

PHENOLICS COMPOSITION, ANTIOXIDANT AND CORROSION INHIBITION EFFICIENCY, CAPACITY OF Fraxinus excelsior EXTRACTS.

2021-09-15T21:04:46+00:00

Objective: In this study, we will determine the antioxidant properties of of Fraxinus excelsior extracts and will correlate the values with total levels of polyphenolic compounds. And the ethyl acetate extract (EAE) was investigated as eco-friendly corrosion inhibitor of carbon steel in 1M HCl has been studied by both electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. Methods: Antioxidant activity was evaluated by DPPH, ABTS⁺, FRAP and enzymatic test. Total polyphenols and total flavonoids contents were evaluated by spectrophotometric assays. And the corrosion inhibition was studied by polarization and electrochemical impedance spectroscopy methods. Results: The total polyphenols and flavonoids contents were in the order EAE > ChE > BolE > MetE > AqE > PEE. The DPPH of MetE, PEE, EAE, ChE, BolE and AqE extract activity expressed as IC₅₀ values were in the order 125.15 ± 2.5, 3722.5 ± 31.82, 23.1 ± 0.48, 101.86 ± 1.64, 106.06 ± 2.97 and 363.41±1.38 µg / ml. The results of ABTS^.⁺, FRAP and the enzymatic test showed that the Fraxinus excelsior extracts have a potential antioxidant activity in the same order obtained by using the DPPH test, which the antioxidant activity followed a decreasing order: EAE > ChE > BolE > MetE > AqE > PEE. The ethyl acetate extract (EAE) exhibits good inhibition properties for the corrosion of carbon steel in 1M HCl solution. Conclusions: In conclusion, Fraxinus excelsior extracts contain active compounds which have antioxidant effects and can be useful in the treatment of pathologies where these activities are neede. And the corrosion inhibition data considered these extract (EAE) as efficient corrosion inhibitor.

EFFECT OF IN VITRO DIGESTION GASTROINTESTINAL OF THE EXTRACT AQUEOU OF LEAVES OF Ugni molinae, ON THE VIABILITY OF COLORECTAL CANCER CELLS

2021-09-15T21:04:46+00:00

Aim: This work is aimed to the study the effect of aqueous extracts obtained from leaves of Ugni molinae and their respective products of in vitro gastrointestinal digestion on the viability of colon cancer cells.

Methods: Ugni molinae leaves were used to prepare a 1%, aqueous extract and with this, an in vitro gastrointestinal digestion was performed, obtaining, fraction products of digestion gastrointestinal (Dgi) and fraction residue. this fraction was identified through liquid chromatography (HPLC-UV) and liquid chromatography-mass spectrometry (HPLC-MS), and then these samples were evaluated in different viability tests, such as trypan blue exclusion, metabolic activity 3-(4,5-di methyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cytotoxicity by lactate dehydrogenase (LDH), on colorectal cancer cells (CaCo-2) and human embryonic kidney 293 cells (HEK) for a period of 24 and 48 hours.

Results and discussion: The aqueous extracts of leaves of Ugni molinae and their digestion fractions caused inhibition of the viability of Caco-2 cells. In most cases, the effect was concentration-dependent and in particular, the only compound that generated inhibition of the viability in all trials corresponded to the Dgi fraction.

Conclusion: The results are favorable, since it is finally is this product that would act in the gastrointestinal tract, interacting with the target cells. These results are important since in most cases, these compounds had effects on cancer cells Caco-2 and not on HEK cells at the same concentrations used in each trial.

COMPARATIVE INSIGHTS INTO HYDROGEN ABSTRACTION OF CCl3H BY SMALL OXYGEN-CONTAINING ANIONS MO− WITH M = Be, B, AND Al

2021-09-15T21:04:46+00:00

In the present work, the considered hydrogen abstraction (HAT) reactions of CCl3H molecule driven by three different small anions MO− (M = Be, B, and Al) have been investigated using electronic structure calculations. While full geometry optimizations were operated to locate all of the relevant stationary points using the DFT-BHandHLYP/aug-cc-pVTZ level, the potential-energy profiles were constructed using the coupled-cluster theory with extrapolation to complete basis set CCSD(T)/CBS. Our theoretical findings suggest that the most favored pathway determined for the HAT reactions mainly stems from the MO− type, namely, for facilitating the HAT pathway the B atom is predicted to be an inherent key in the BO−-reaction whereas it becomes O atom in both BeO−- and AlO−-reactions. Of the three favored pathways obtained here, the activations of the CCl3H in the presence of both BeO− and AlO− anions are significantly efficient, in which the energy barrier for the cleavage of the C-H bond with the assistance of BeO− was to be relatively low. Again, through the transition state theory the rate constants at 298-1000 K are also evaluated for the most favored HAT reactions studied here, indicating the lower the temperature, the faster the BO− chemical reaction.

VOLATILE PROFILE AND CONSUMER ACCEPTABILITY OF NATURAL YOGHURTS ELABORATED WITH CHILEAN NATIVE CULTURES OF Enterococcus sp. STRAIN BB3 AND Lactobacillus sp. STRAIN BB6

2021-09-15T21:04:46+00:00

According to WHO, in 2016 around 13% of the world's adult population (11% of men and 15% of women) were obese. The global prevalence of obesity almost tripled between 1975 and 2016. In this context, it is important to note that the continuous increase in life expectancy, the desire for a better quality of life, and the high cost of medical care have led to a growing demand for functional foods in the market. People have started to realize that their food choices and their unhealthy lifestyles have consequences for their health. An important role in this scenario is associated with functional foods containing probiotic strains, reported to be beneficial for human health. Here we report the development of natural yoghurts based on native probiotic starter cultures of Enterococcus sp. strain BB3 (MK681869) and Lactobacillus sp. strain BB6 (MK681868), isolated from raw cow milk of La Araucanía region of Chile. The odour and taste were the main parameter criticized by the consumer, the analysis of CG-MS elucidated that the yoghurt produced by the strain Enterococcus sp. strain BB3 (MK681869) produced a higher amount of heptan-2-one, associated with a cheesy type odour, with less acceptance by the consumers. The acceptability of 6 types of yoghurt was evaluated with a randomized analysis of 60 participants. The development of a functional dairy product based on probiotics is of interest because of its relation with positive changes in gut microbiota, and at the same time with a possible decrease in body weight.

PHYTOCHEMICAL ASSESSMENT, TOTAL PHENOLIC CONTENT, CYTOTOXIC, ANTIOXIDANT AND ANTIDIABETIC ACTIVITIES OF Hyoscyamus insanus

2021-09-15T21:04:46+00:00

Abstract

Hyoscyamus insanus (family Solanaceae) was traditionally used for treatment of asthma, relieving pain and increasing female body weight. The present projects was intended to assess the phytochemicals, total phenolic content, cytotoxic, antioxidant and antidiabetic activities of Hyoscyamus insanus leaves methanolic extract and its special fractions. After extraction, the methanolic extract was sequentially fractionated with hexane, chloroform and water followed by phytochemicals analysis of each sample. Brine shrimp lethality bioassay, Folin-Ciocalteu phenol reagent, DPPH, ABTS^•+, H₂O₂ and α-amylase inhibition assay were employed for the assessment of cytotoxic property, total phenolic contents, antioxidant and anti-diabetic potency of methanolic extract and its fractions. Amino acids and protein, carbohydrates, flavonoids and saponins were found in the methanolic extract and aqueous fraction while chloroform fraction exhibited carbohydrates, flavonoids and saponins. The highest cytotoxic activity (80.6±1.2%) was exhibited by methanolic extract while maximum phenolic contents (21.93±1.17 mg GAE/g) were found in the chloroform fraction. The employed antioxidant assays expressed different results i.e. methanolic extract demonstrated highest 83.99%, 74.19% and 51.15% free radical scavenging characteristics in ABTS, DPPH and H₂O₂ assays respectively. The methanolic extract showed significant (53.44%) antidiabetic properties. The correlation of total phenolic contents with percentage antioxidant and anti-diabetic capabilities of methanolic extract and its special fractions was observed to be non-significant (P> 0.05). It is concluded that the Hyoscyamus insanus is a potential source of phenolic, cytotoxic, antioxidant and antidiabetic compounds.

A COMPUTATIONAL STUDY OF STEVIOL AND ITS SUGGESTED ANTICANCER ACTIVITY. A DFT AND DOCKING STUDY.

2021-09-15T21:04:46+00:00

In the present, study we analyzed the electronic properties of Steviol, the Stevia rebaudiana metabolite, and its interaction with antiapoptotic protein BCL-2. The ionization potential and electrophilicity index values were evaluated in the framework of the DFT, and these values suggest that Steviol may form ligand-receptor interactions. Also, the bond dissociation energy and the electrostatic potential distribution of Steviol reveal its antioxidant behavior. Docking studies were performed to evaluate the feasibility of this molecule to interact with antiapoptotic protein BCL-2. However, no hydrogen bonds were found in the pocket site, instead six interactions, including alkyl and π-alkyl type were formed, suggesting that the possible most feasible mechanism for anticancer activity would be through free radicals scavenging.

BIOACTIVE METAL COMPLEXES OF Cu(II), Ni(II), AND Zn(II) IONS CONTAINING N-ISONICOTINAMIDO-THIOPHENE-2-CARBALDIMINE SCHIFF BASE AND 1, 10-PHENANTHROLINE: SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL AND ANTIOXIDANT PROPERTIES

2021-09-15T21:04:46+00:00

A series of transition metal complexes having general formula [M(Lb)(L1)](NO₃)₂, (where, M = Cu(II), Ni(II), and Zn(II)) of mixed ligands, Lb = N-Isonicotinamido-Thiophene-2-Carbaldimine, L1 = 1, 10-phenanthroline, were synthesized. The obtained compounds were successfully characterized by different spectroscopic techniques. Conductivity measurements indicated that all complexes were 1:2 electrolytes in nature. IR spectra indicated that ligands coordinated to metals via the carbonyl oxygen atom and the azomethine nitrogen atom. Magnetic moment values and UV-Visible spectra confirmed square planar structure around the Cu(II), and Ni(II) ions, and a tetrahedral geometry around the Zn(II) ion. The metal complexes of Lb and L1 were tested against Escherichia coli and Pseudomonas sp. Among the tested compounds, Zn(II)complex showed higher antibacterial activity over both bacterial strains against reference drug Kanamycin. Moreover, synthesized metal complexes exhibited moderate antioxidant activity than the Schiff base. Cu(II) complexes were found to be most active whereas, Zn(II) complexes showed the lowest antioxidant activity comparable to the BHT.

ANTI-OXIDANT AND ANTI-INFLAMMATORY POTENTIAL OF SECONDARY METABOLITES FROM Daphne mucronata ROYLE AND THEIR FIRST-PRINCIPLES INVESTIGATIONS

2021-09-15T21:04:46+00:00

Ten coumarin class of compounds, including new fused coumarinolignoids namely, mucronin-C (1) were isolated from the methanol extract from whole plant of Daphne mucronata Royle. The structures of mucronin-C (1) and its configurations were determined by chemical and spectroscopic methods including 1DNMR, 2D-NMR and HR-FAB-MS. The isolated compounds 1-10 were evaluated for in-vitro biological activities. The anti-inflammatory (lipoxygenase) activities of compound 1, 4, 8, 9 and 10 (IC₅₀= 21.7, 23.7, 25.1, 27.3 and 26.0 µg/mL, respectively) were higher compared with standard Quercetin (IC₅₀ = 22.5 µg/mL). The antioxidant property of coumarin as evaluated by DPPH scavenging bioassay was significantly greater in compounds 1-5, 9 and 10 (IC₅₀= 0.7, 0.8, 1.9, 2.3, 2.8, 0.5 and 2.1 µg/mL respectively) as standard Trolox (IC₅₀ = 0.3 µg/mL). The density functional descriptors in the progress of quantitative structure-activity relationship (QSAR) are significant to analyze the reactive sites and antioxidant ability of compounds. We have explored the reactive sites and radical scavenging activity of studied coumarin derivatives by shedding light on electron affinity, ionization potential, molecular electrostatic potential, frontier molecular orbitals and molecular descriptors analysis. First-principles calculations about one-electron transfer mechanism revealed that smaller ionization potential value of Compounds 1-5, 9 and 10 are leading to superior antioxidant activity, which is in good agreement with the experimental data.

IMPACT OF COVID-19 LOCKDOWN ON NO2, NOX, O3 AND PM2,5 CONCENTRATIONS IN SANTIAGO DE CHILE

2021-09-28T21:31:22+00:00

Based on the spread of the COVID-2019, a lockdown was declared in the Santiago Metropolitan area in Chile. The application of containment measures allowed to reduce the impact of the COVID-2019 pandemic on the National Health System (MINSAL) but at the same time these restriction measures gave also the opportunity to assess the effect of anthropogenic activities on air pollutants. A comparative study of typical behavior of atmospheric pollutants O₃, NO₂, NO_xand PM_2.5 during the years 2015-2020 are presented.

For the eight studied stations (Las Condes, Pudahuel, El Bosque, Cerro Navia, La Florida, Independencia, Parque O`Higgins and Puente Alto) it was possible to determine the seasonal variation of NO₂, NOx, O₃ and PM_2.5.

As results of impact of the lockdown, in this paper we have been determined a significant reduction of pollutants concentration mainly due to vehicular traffic.