Diogo Siebert - Academia.edu (original) (raw)

Papers by Diogo Siebert

Phenolic compounds of Eugenia involucrata (Myrtaceae) extracts and associated antioxidant and inh... more Phenolic compounds of Eugenia involucrata (Myrtaceae) extracts and associated antioxidant and inhibitory effects on acetylcholinesterase and α-glucosidase Eugenia involucrata DC. (Myrtaceae), popularly known as "cereja-do-Rio-Grande", is a native tree from Brazil, popularly used as a hypoglycemiant. Crude hydroalcoholic extract (CHE) and fractions (insoluble (FI), dichloromethane (FDM), ethyl acetate (FEA) and butanol (FBu) of leaves were assessed to determine the phenolic chemical composition by HPLC-ESI-MS/MS. 10 compounds were identified, being 7 new for this species: rutin, isoquercitrin, luteolin-7-O-rutinoside, mandelic acid, naringenin, luteolin-7-O-glucoside and salicylic acid. Extract and fractions showed inhibitory activity on acetylcholinesterase (AchE) enzyme (best result: IC 50 = 44.19 µg mL-1 , for FEA) and α-glucosidase (α-Glu) (best result: IC 50 = 31.25 ± 0.15 µg mL-1 , for CHE). The observed antioxidant and inhibitory activity on the AchE and α-Glu is due to, at least in part, the presence of phenolic compounds in the samples.

Natural Product Research, 2020

This study describes anti-inflamatory activity of epicuticular wax (ECW) extracted from leaves of... more This study describes anti-inflamatory activity of epicuticular wax (ECW) extracted from leaves of Eugenia brasiliensis Lam., and its isolated compounds, catechin and gallocatechin in a pleurisy model in mice. The results for exudation and cell migration showed that the extract and isolated compounds from the plant were effective in inhibiting these inflammatory parameters. The ECW demonstrated a dose-dependent effect on the inhibition of cell migration. The results for NO x levels reveals that the isolated compounds from Eugenia brasiliensis were effective in inhibiting the production of this inflammatory mediator, however, ECW were not able in inhibiting the production of NO in the pleural cavity, at the tested doses. The results here obtained, helps to reinforce the scientifically hypothesis that E. brasiliensis has an important anti-inflammatory activity, and that this effect may be, at least in part, by the presence of the compounds catechin and gallocatechin.

Rodriguésia, 2020

Myrcia splendens is popularly known as “guamirim-de-folha-miúda”, and its occurrence ranges from ... more Myrcia splendens is popularly known as “guamirim-de-folha-miúda”, and its occurrence ranges from Mexico to southern Brazil. The aim of this work was to identify and quantify phenolic compounds in the crude hydroalcoholic (EBH), ethyl acetate (EBAE) and dichloromethane (EBDM) extracts using the HPLC-ESI- MS/MS. In total, 15 compounds, including protocatecuic acid, syringic acid, p-coumaric acid, salicylic acid, isoquercetin, ellagic acid, ferulic acid, umbelliferone, coniferaldehyde, sinapaldehyde, carnosol, gallic acid, syringaldehyde, umbelliferone, coniferaldehyde, myricetin and kaempferol were identified. Ellagic acid was the major compound in all extracts.

Natural Product Research, 2020

Phenolic profile of crude extract and fractions by HPLC-ESI-MS/MS and enzymatic inhibitory activi... more Phenolic profile of crude extract and fractions by HPLC-ESI-MS/MS and enzymatic inhibitory activity of Bryophyllum delagoense leaves Bryophyllum delagoense (Eckl. & Zeyh.) Druce, native to Madagascar, is popularly known as "abyssian cactus" and popularly used in folk medicine as an analgesic and healing agent. The study methodology was divided into the phytochemical study: fractionation and identification of phenolic compounds by HLPC-ESI-MS/MS from the methanolic extract (ME), and fractions (DCMF and EAF) of leaves of B. delagoense, and biological activity with acetylcholinesterase and α-glucosidase inhibition of extracts and fractions by in vitro enzymatic techniques. Twenty-seven phenolic compounds were identified, being the highest concentration of syringic acid (87.848 mg g-1). The DCMF fraction showed the best biological activity for inhibition of α-glucosidase enzyme (0.125 mg mL-1).

Revista Pan-Amazônica de Saúde, 2020

Os estudos de substâncias obtidas de vegetais vêm adquirindo novas perspectivas, em razão dos pro... more Os estudos de substâncias obtidas de vegetais vêm adquirindo novas perspectivas, em razão dos problemas associados à terapêutica de diversas infecções, principalmente no que diz respeito à resistência aos antimicrobianos. OBJETIVOS: Avaliar a atividade antibacteriana de plantas medicinais, frente a diferentes espécies de bactérias, bem como analisar seus perfis cromatográficos. MATERIAIS E MÉTODOS: Foram obtidos o extrato hidroalcoólico e as frações diclorometano, acetato de etila, n-butanol e aquosa das plantas Alternanthera brasiliana, Plantago major, Arctostaphylos uva-ursi e Phyllanthus niruri, que foram testados pelo método de microdiluição em caldo utilizando-se cepas de Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, Escherichia coli, Staphylococcus aureus, Staphylococcus saprophyticus, Proteus mirabilis e Klebsiella pneumoniae. Com isso, foi determinada a concentração inibitória mínima (CIM) das amostras. O perfil cromatográfico dos extratos e frações foi determinado por meio da técnica de cromatografia em camada delgada. RESULTADOS: A fração acetato de etila de A. uva-ursi apresentou CIM de 125 µg/mL contra M. genitalium e de 31,25 µg/mL contra S. aureus, sendo essa última uma atividade antibacteriana excelente. Para a mesma fração, P. niruri apresentou atividade antibacteriana moderada, com valores de CIM de 250 µg/mL contra M. genitalium e S. aureus. As espécies A. brasiliana e P. major apresentaram fraca ou nenhuma atividade contras as cepas testadas. CONCLUSÃO: Não foi possível estabelecer uma estreita relação entre o uso popular, a atividade antibacteriana in vitro e o perfil fitoquímico das plantas, uma vez que os efeitos antibacterianos das espécies vegetais estudadas variaram frente às diferentes bactérias com e sem parede celular.

Natural Product Research, 2019

Eugenia genus is known for the presence of phenolic metabolites, which may influence Alzheimer Di... more Eugenia genus is known for the presence of phenolic metabolites, which may influence Alzheimer Disease's progression. This study aimed to evaluate the anticholinesterase effects of six Eugenia species from Brazil. Leaves and stems were submitted to maceration (methanol, 7 days) and then partitioned with dichloromethane and ethyl acetate. Samples were screened (200 μg/mL) for anticholinesterase activity. HPLC-ESI-MS/MS analysis was performed and twenty-eight phenolic compounds were identified. Regarding the pharmacological activity, better results were observed for the ethyl acetate fraction of E. brevistyla, E. catharinae and especially E. mattosii. Chemical and pharmacological aspects of seasonal E. mattosii extracts were evaluated. The winter leaves extract was the most effective for AChE, and the spring leaves extract was the most effective for BuChE. Correlating the pharmacological results with the chemical data, it was possible to associate these effects to isoquercitrin, quercetin, catechin, epicatechin, procatecuic acid, and myricitrin presence.

Electroanalysis, 2019

A novel silsesquioxane material was synthetized and used as a stabilizing agent for silver nanopa... more A novel silsesquioxane material was synthetized and used as a stabilizing agent for silver nanoparticles. This hybrid material was characterized by FTIR, 29 Si CP-MAS NMR, 13 C DEPT 135°NMR and TGA techniques and the silver nanoparticles were characterized from DLS, UV-Vis spectroscopy, zeta-potential, TEM and SAXS results. The silver nanoparticles obtained were spherical in shape with a diameter of 3.74 nm. The nanomaterial was successfully applied in the modification of a glassy carbon electrode and a pronounced current response was obtained in the determination of the biomarker 4-nitrophenol. Quantum chemical calculations, using density functional theory, were also performed in order to evaluate the redox properties of the analyte. Two different linear ranges were obtained applying optimal square wave voltammetry conditions. The reduction peak currents obtained were linear for 4-NP concentrations in the ranges of 0.29 to 1.50 μmol L À 1 (E d = À 0.6 V and t d = 20 s) and 2.75 to 31.5 μmol L À 1 , with a theoretical (signal to noise = 3) limit of detection of 0.05 μmol L À 1 (t d = 20 s). The proposed method was successfully applied to the determination of 4-NP in synthetic serum samples at different levels of 4-NP with a recovery range of 94-101 %. Validation was performed using a comparative method through the capillary electrophoresis (CE) technique.

Journal of Ethnopharmacology, 2019

ETHNOPHARMACOLOGICAL RELEVANCE Bauhinia forficata Link, commonly known as "cow's paw&quo... more ETHNOPHARMACOLOGICAL RELEVANCE Bauhinia forficata Link, commonly known as "cow's paw", is a native plant from South America. Its leaves are widely used in Brazilian folk medicine to treat diabetes and cardiovascular disorders. Although this species' biological potential has been extensively proven as an antidiabetic, anti-inflammatory and antioxidant agent, there is a lack of studies to evidence its action on the cardiovascular system. AIM OF THE STUDY This study was designed to investigate the vascular effects of B. forficata leaves preparations and its majority compound kaempferitrin, as well as its aglycone form kaempferol, in rat aortic rings of normotensive (NTR) and hypertensive (SHR) rats. MATERIALS AND METHODS Aorta rings from NTR and SHR precontracted with phenylephrine were exposed to cumulative concentrations of B. forficata extract, fractions (1-50 μg/mL) and compounds (0.001-0.3 μg/mL). The mechanisms involved in the vasorelaxant effect of ethyl-acetate plus butanol fraction (EAButF) were also evaluated. RESULTS Although kaempferitrin is the most abundant compound found in both methanolic extract and EAButF, 24 minor phenolic compounds were identified in B. forficata leaves, including kaempferol. EAButF was the only with endothelium-dependent and independent vasorelaxant properties in both NTR and SHR. The incubation with L-NAME or ODQ completely blocked EAButF-induced vasorelaxation. On the other hand, the incubation with propranolol, atropine, indomethacin, glibenclamide or barium chloride did not change the vasorelaxant activity of EAButF (50 μg/mL). Nevertheless, the incubation with tetraethylammonium and 4-aminopyridine significantly influenced the EAButF activity. It was also shown that Ca2+ influx or efflux is not related to EAButF vasorelaxation potential. Kaempferitrin and kaempferol were also able to relax the rat aortic rings in 34.70% and 40.54%, respectively. CONCLUSIONS This study shows, for the first time, the vasorelaxant effect of EAButF from B. forficata leaves, an effect that may be attributed to the modulation of vascular tone through nitric oxide/soluble guanylate cyclase pathway, and potassium channels. The bioactive kaempferitrin and kaempferol seem to be important for the effects observed with the fraction. Finally, preparations obtained from the leaves of B. forficata may be interesting candidates for new or complementary strategies regarding cardiovascular diseases.

Revista Virtual de Química, 2019

The aim of this study was to evaluate the biological potential of the crude hydroalcoholic extrac... more The aim of this study was to evaluate the biological potential of the crude hydroalcoholic extract (EBH) and fractions (FAcOEt and FBuOH) from the roots of Dioscorea scabra. The EBH and its fractions were submitted to antimicrobial activity tests against bacteria with and without cell-wall, and yeasts from the Candida genus. The phytochemical profile of EBH was determined by colorimetric assays and analysis by HPLC in comparison to standard diosgenin. Phytochemical analysis showed the presence of phenols, tannins, flavonoids, xanthones, catechins, steroids, free triterpenoids and saponins, characteristics of the genus. By HPLC analysis, it was possible to identify the presence of diosgenin in the analysed extract. The species was active against all tested bacterial strains, being FBuOH the most active against Mycoplasma arginini species. In the antifungal activity test, samples showed activity against Candida albicans, C. parapsilosis and C. glabrata, with the EBH and FBuOH showing the best results.

Microchemical Journal, 2019

Several restorers of paintings have reported the sensitivity of oil paints toward polar solvents ... more Several restorers of paintings have reported the sensitivity of oil paints toward polar solvents during the chemical cleaning of the surface of the pictorial layer. In this study, a novel mechanism for this phenomenon is described based on the chemical analysis of the pictorial layer of a nineteenth century painting and the swab used in the cleaning of this layer. The pigments used were characterized by FTIR and SEM-EDS and the presence of kaolinite, aclay mineral, was observed in all areas that showed sensitivity. The binder was characterized by GC-MS as a mixture of linseed and walnut oils. SEM analysis showed the presence of pigments adhered to the cotton as well as the presence of kaolinite. GC-MS results for the swab showed the absence of oil in the paint traces present.Thus, the oil and its degradation products are not sensitive toward the polar solvent, but only the pigmentand the kaolinite. Since kaolinite is hygroscopic, it aids the leaching of the pigment of the oil layer onto the swab containing the polar solvent.

Natural Product Research, 2019

Alzheimer's disease and diabetes mellitus are contemporary diseases of great concern. Phenolic co... more Alzheimer's disease and diabetes mellitus are contemporary diseases of great concern. Phenolic compounds are linked to several health benefits and could lead to novel strategies to combat these ailments. The objective of this study was to evaluate by electrophoretically-mediated microanalysis the potential inhibitory activity of the fruit juices from Plinia cauliflora ("jaboticaba") and Eugenia uniflora ("pitanga") toward acetylcholinesterase (AChE) and α-glucosidase, target enzymes in strategies for the treatment of these diseases. The phenolic profiles of the samples were also investigated. Jaboticaba and pitanga juices

Metabolic Brain Disease, 2018

This work investigated the antioxidant and antidepressant-like effects of ethyl acetate extract f... more This work investigated the antioxidant and antidepressant-like effects of ethyl acetate extract from Eugenia catharinensis in mice treated with corticosterone (20 mg/Kg). The animals received saline or corticosterone (21 days) and, in the last 7 days, they were treated with the extract (50, 125, 200 or 250 mg/Kg) or vehicle. After 24 h, the mice were submitted to the open field and forced swimming tests, after which the hippocampus and cerebral cortex were removed. Our results showed that the extract decreased the immobility time of mice in the forced swimming test and that the extract was able to reverse the effect caused by corticosterone. Corticosterone pre-treatment generated oxidative stress, altering antioxidant enzymes in the nervous tissue. The extract increased the catalase and superoxide dismutase activities and reversed the effects of corticosterone. In the hippocampus, the extract increased superoxide dismutase activity and reversed the increase in catalase activity elicited by corticosterone. We propose that the effects elicited by the Eugenia catharinensis are dependent on the presence of phenolic compounds (gallic acid, protocatechuic acid, syringic acid, 4-hydroxy methylbenzoic acid, chlorogenic acid, salicylic acid, caffeic acid, vanillic acid, pcoumaric acid, isoquercetin, rutin, ferulic acid, aromadendrin, galangin and apigenin) in this extract, as demonstrated by HPLC-ESI-MS/MS.

Journal of ethnopharmacology, Jan 10, 2018

Eugenia brasiliensis Lam. (Myrtaceae) is a Brazilian tree distributed throughout Atlantic rain fo... more Eugenia brasiliensis Lam. (Myrtaceae) is a Brazilian tree distributed throughout Atlantic rain forest, since Bahia until Santa Catarina state, and is popularly known as "grumixaba, grumixameira, cumbixaba, ibaporoiti, and cereja-brasileira". The bark and leaves of Eugenia brasiliensis are used in folk medicine as adstringent, diuretic, energizing, anti-rheumatic and anti-inflammatory. This study aimed at investigating the chemical composition, antinociceptive and anti-inflammatory effect of the hydroalcoholic extract of Eugenia brasiliensis (HEEb). Chemical composition of the HEEb was determined by High Performance Liquid Chromatography/ESI-Mass Spectrometry (HPLC-ESI-MS/MS). The antinociceptive and anti-inflammatory effects of HEEb (30-300 mg/kg) was verified in mice after oral administration by intra-gastric gavage (i.g.) 60 min prior to experimentation. It was investigated whether HEEb decreases visceral pain and leukocyte migration induced by an intraperitoneal (i.p.) ...

Natural Product Research, 2017

Abstract This study evaluates the antidepressant-like effect and analysed the qualitative and qua... more Abstract This study evaluates the antidepressant-like effect and analysed the qualitative and quantitative 74 phenolic standards of ethyl acetate fraction from Tabernaemontana catharinensis leaves. Acute administration of fraction in mice reduced the immobility time in forced swimming and tail suspension tests confirming its antidepressant-like activity. The anti-immobility effect elicited by this fraction was prevented by the pretreatment of mice with PCPA (100 mg kg−1), ketanserin (5 mg kg−1), SCH 23,390 (0.05 mg kg−1) or yohimbine (1 mg kg−1). A sub effective dose of the fraction produced a synergistic effect with fluoxetine (5 mg kg−1). Chromatographic analysis identified 4-hydroxybenzoic and p-coumaric acids in the ethyl acetate fraction from T. catharinensis. Capillary electrophoresis presented 7.34 ± 0.02 mg g−1 of p-coumaric acid concentration in the fraction. Therefore, it is possible that antidepressant-like effect elicited by ethyl acetate fraction from T. catharinensis be dependent on the p-coumaric acid.

Revista Brasileira de Farmacognosia, 2017

Eugenia brasiliensis Lam., Myrtaceae, is used in folk medicine for anti-inflammatory diseases suc... more Eugenia brasiliensis Lam., Myrtaceae, is used in folk medicine for anti-inflammatory diseases such as arthritis and rheumatism. This study investigated the anti-inflammatory activity and phenolic profile of the crude hydroalcoholic extract and ethyl acetate fraction from E. brasiliensis leaves. Crude hydroalcoholic extract and the ethyl acetate fraction were analyzed by HPLC-ESI-MS/MS in comparison to standard phenolic compounds. The anti-inflammatory activity of the crude hydroalcoholic extract (1, 10 and 25 mg kg −1) and the ethyl acetate fraction (10, 25 and 50 mg kg −1) was evaluated in a swiss mouse model of acute pleurisy induced by carrageenan, being the total cell count, exudation and analysis of nitrite/nitrate the inflammation parameters. HPLC-ESI-MS/MS analysis revealed apigenin, catechin, galangin, isoquercetin, myricetin, quercetin and rutin. Crude hydroalcoholic extract and ethyl acetate fraction were effective in inhibiting cell migration in all tested doses. Crude hydroalcoholic extract was effective in inhibiting exudation only at the 10 mg kg −1 dose; ethyl acetate fraction was effective in all tested doses. Results for nitrite/nitrate levels reveals that only the ethyl acetate fraction was effective at the tested doses. This is the first report of the presence of isoquercetin, galangin and apigenin in this species. Results from the phytochemical analysis enhance the chemical knowledge of this species. In the future, together with more studies, validation of its popular use in inflammatory diseases is possible.

Natural Product Research, 2015

Preservatives used in the food industry are undergoing increasing scrutiny and reappraisal. There... more Preservatives used in the food industry are undergoing increasing scrutiny and reappraisal. There is therefore a renewed interest in the antimicrobial properties of herbs and spices. Rosemary (Rosmarinus officinalis L.) belonging to the Lamiaceae family, is a pleasant-smelling perennial herb. The antimicrobial activities of the R. officinalis oil against Leuconostoc mesenteroides (PTCC1591), Lactobacillus delbruekii (PTCC1333), Saccharomyces cerevisia (PTCC5269) and Candida krusei (PTCC 5295) were determined. The results indicate that among the tested microbes, the essential oil had a stronger inhibitory effect on the bacteria as compared to yeasts. Minimum inhibitory concentration (MIC) values for bacteria L. mesenteroides, L. delbruekii, S. cerevisia and C. krusei ranged between 0.5 and 1.5 mg/ml. The oil was analyzed by GC and GC/MS. The major components of R. officinalis oil were 1,8-cineole (23.14%), camphor (12.35%), α-pinene (9.87%), β-pinene (6.10%), borneol (5.61%), camphene (5.58%) and α-terpineol (4.30%), respectively. These results indicate the latent potency of essential oil of R. officinalis as a natural preservative in food products against L. mesenteroides, L. delbruekii, S. cerevisia and C.krusei.

Natural Product Research, 2014

This study describes the seasonal composition and the antibacterial, antioxidant and anticholines... more This study describes the seasonal composition and the antibacterial, antioxidant and anticholinesterase activity of the essential oil from Eugenia brasiliensis leaves. Analysis by using GC allowed the identification of 40 compounds. It was observed that the monoterpenes varied more (42%) than the sesquiterpenes (14%), and that the monoterpene hydrocarbons suffered the greatest variation throughout the year (64%). Major compounds were spathulenol in the spring (16.02 ± 0.44%) and summer (18.17 ± 0.41%), τ-cadinol in the autumn (12.83 ± 0.03%) and α-pinene (15.94 ± 0.58%) in the winter. Essential oils were tested for their antibacterial activity, and the best result was obtained from the autumn oil, with MIC = 500 μg mL(- 1) against Staphylococcus saprophyticus and Pseudomonas aeruginosa. Antioxidant activity was evaluated using DPPH, lipid peroxidation and iron-reducing power assays, as well as the anticholinesterase activity. Both tests showed a weak performance of the essential oils.

International Journal of Clinical Medicine, 2014

Background: Diabetes Mellitus (DM) is one of the major health problems and morbidity causes in co... more Background: Diabetes Mellitus (DM) is one of the major health problems and morbidity causes in contemporary society worldwide. Recently, it has been suggested that the addition of citrate in plasma extraction decreases glucose degradation by endogenous enzymes, which could contribute in an important manner to the diagnosis of DM. However, this strategy has not been sufficiently evaluated. The present study aimed to evaluate glucose determination in serum and in plasma obtained with different anticoagulants. Methods: We obtained 20 venous blood paired samples on consecutive days from the same individual, collected in dry tubes with separator gel and in glass tubes with sodium fluoride and EDTA-K2, either in the presence or absence of sodium citrate. Glucose was determined by an oxidase/peroxidase method using the same system by a unique analyst. Results: Serum determinations were constantly higher than in plasma (P < 0.02), and the addition of citrate increased the analytical variability. Conclusions: Our results were highly relevant statistically, and did not corroborate the addition of citrate in plasma extraction for the inhibition of glycolysis, at least using the standard anticoagulant concentrations.

Applied Biochemistry and Biotechnology, 2020

The studies on natural compounds to diabetes mellitus treatment have been increasing in recent ye... more The studies on natural compounds to diabetes mellitus treatment have been increasing in recent years. Research suggests that natural components can inhibit alpha-glucosidase activities, an important strategy in the management of blood glucose levels. In this work, for the first time in the literature, the compounds produced by Ganoderma lipsiense extracts were identified and evaluated on the inhibitory effect of these on alphaglucosidase activity. Four phenolic compounds were identified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) to crude extract from G. lipsiense grown in red rice medium (RCE) and synthetic medium (SCE), being syringic acid identified in both extracts. Gas chromatography-mass spectrometry (GC-MS) analysis showed fatty acids and their derivatives, terpene, steroid, niacin, and nitrogen compounds to SCE, while RCE was rich in fatty acids and their derivatives. Both extracts demonstrated alpha-glucosidase inhibition (RCE IC 50 = 0.269 ± 8.25 mg mL −1 ; SCE IC 50 = 0.218 ± 9.67 mg mL −1), and the purified hexane fraction of RCE (RHEX) demonstrated the highest inhibition of enzyme (81.1%). Studies on kinetic inhibition showed competitive inhibition mode to RCE, while SCE showed uncompetitive inhibition mode. Although the inhibitory effects of RCE and SCE were satisfactory, the present findings identified some unpublished compounds to G. lipsiense in the literature with important therapeutic properties.

Phenolic compounds of Eugenia involucrata (Myrtaceae) extracts and associated antioxidant and inh... more Phenolic compounds of Eugenia involucrata (Myrtaceae) extracts and associated antioxidant and inhibitory effects on acetylcholinesterase and α-glucosidase Eugenia involucrata DC. (Myrtaceae), popularly known as "cereja-do-Rio-Grande", is a native tree from Brazil, popularly used as a hypoglycemiant. Crude hydroalcoholic extract (CHE) and fractions (insoluble (FI), dichloromethane (FDM), ethyl acetate (FEA) and butanol (FBu) of leaves were assessed to determine the phenolic chemical composition by HPLC-ESI-MS/MS. 10 compounds were identified, being 7 new for this species: rutin, isoquercitrin, luteolin-7-O-rutinoside, mandelic acid, naringenin, luteolin-7-O-glucoside and salicylic acid. Extract and fractions showed inhibitory activity on acetylcholinesterase (AchE) enzyme (best result: IC 50 = 44.19 µg mL-1 , for FEA) and α-glucosidase (α-Glu) (best result: IC 50 = 31.25 ± 0.15 µg mL-1 , for CHE). The observed antioxidant and inhibitory activity on the AchE and α-Glu is due to, at least in part, the presence of phenolic compounds in the samples.

Natural Product Research, 2020

This study describes anti-inflamatory activity of epicuticular wax (ECW) extracted from leaves of... more This study describes anti-inflamatory activity of epicuticular wax (ECW) extracted from leaves of Eugenia brasiliensis Lam., and its isolated compounds, catechin and gallocatechin in a pleurisy model in mice. The results for exudation and cell migration showed that the extract and isolated compounds from the plant were effective in inhibiting these inflammatory parameters. The ECW demonstrated a dose-dependent effect on the inhibition of cell migration. The results for NO x levels reveals that the isolated compounds from Eugenia brasiliensis were effective in inhibiting the production of this inflammatory mediator, however, ECW were not able in inhibiting the production of NO in the pleural cavity, at the tested doses. The results here obtained, helps to reinforce the scientifically hypothesis that E. brasiliensis has an important anti-inflammatory activity, and that this effect may be, at least in part, by the presence of the compounds catechin and gallocatechin.

Rodriguésia, 2020

Myrcia splendens is popularly known as “guamirim-de-folha-miúda”, and its occurrence ranges from ... more Myrcia splendens is popularly known as “guamirim-de-folha-miúda”, and its occurrence ranges from Mexico to southern Brazil. The aim of this work was to identify and quantify phenolic compounds in the crude hydroalcoholic (EBH), ethyl acetate (EBAE) and dichloromethane (EBDM) extracts using the HPLC-ESI- MS/MS. In total, 15 compounds, including protocatecuic acid, syringic acid, p-coumaric acid, salicylic acid, isoquercetin, ellagic acid, ferulic acid, umbelliferone, coniferaldehyde, sinapaldehyde, carnosol, gallic acid, syringaldehyde, umbelliferone, coniferaldehyde, myricetin and kaempferol were identified. Ellagic acid was the major compound in all extracts.

Natural Product Research, 2020

Phenolic profile of crude extract and fractions by HPLC-ESI-MS/MS and enzymatic inhibitory activi... more Phenolic profile of crude extract and fractions by HPLC-ESI-MS/MS and enzymatic inhibitory activity of Bryophyllum delagoense leaves Bryophyllum delagoense (Eckl. & Zeyh.) Druce, native to Madagascar, is popularly known as "abyssian cactus" and popularly used in folk medicine as an analgesic and healing agent. The study methodology was divided into the phytochemical study: fractionation and identification of phenolic compounds by HLPC-ESI-MS/MS from the methanolic extract (ME), and fractions (DCMF and EAF) of leaves of B. delagoense, and biological activity with acetylcholinesterase and α-glucosidase inhibition of extracts and fractions by in vitro enzymatic techniques. Twenty-seven phenolic compounds were identified, being the highest concentration of syringic acid (87.848 mg g-1). The DCMF fraction showed the best biological activity for inhibition of α-glucosidase enzyme (0.125 mg mL-1).

Revista Pan-Amazônica de Saúde, 2020

Os estudos de substâncias obtidas de vegetais vêm adquirindo novas perspectivas, em razão dos pro... more Os estudos de substâncias obtidas de vegetais vêm adquirindo novas perspectivas, em razão dos problemas associados à terapêutica de diversas infecções, principalmente no que diz respeito à resistência aos antimicrobianos. OBJETIVOS: Avaliar a atividade antibacteriana de plantas medicinais, frente a diferentes espécies de bactérias, bem como analisar seus perfis cromatográficos. MATERIAIS E MÉTODOS: Foram obtidos o extrato hidroalcoólico e as frações diclorometano, acetato de etila, n-butanol e aquosa das plantas Alternanthera brasiliana, Plantago major, Arctostaphylos uva-ursi e Phyllanthus niruri, que foram testados pelo método de microdiluição em caldo utilizando-se cepas de Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, Escherichia coli, Staphylococcus aureus, Staphylococcus saprophyticus, Proteus mirabilis e Klebsiella pneumoniae. Com isso, foi determinada a concentração inibitória mínima (CIM) das amostras. O perfil cromatográfico dos extratos e frações foi determinado por meio da técnica de cromatografia em camada delgada. RESULTADOS: A fração acetato de etila de A. uva-ursi apresentou CIM de 125 µg/mL contra M. genitalium e de 31,25 µg/mL contra S. aureus, sendo essa última uma atividade antibacteriana excelente. Para a mesma fração, P. niruri apresentou atividade antibacteriana moderada, com valores de CIM de 250 µg/mL contra M. genitalium e S. aureus. As espécies A. brasiliana e P. major apresentaram fraca ou nenhuma atividade contras as cepas testadas. CONCLUSÃO: Não foi possível estabelecer uma estreita relação entre o uso popular, a atividade antibacteriana in vitro e o perfil fitoquímico das plantas, uma vez que os efeitos antibacterianos das espécies vegetais estudadas variaram frente às diferentes bactérias com e sem parede celular.

Natural Product Research, 2019

Eugenia genus is known for the presence of phenolic metabolites, which may influence Alzheimer Di... more Eugenia genus is known for the presence of phenolic metabolites, which may influence Alzheimer Disease's progression. This study aimed to evaluate the anticholinesterase effects of six Eugenia species from Brazil. Leaves and stems were submitted to maceration (methanol, 7 days) and then partitioned with dichloromethane and ethyl acetate. Samples were screened (200 μg/mL) for anticholinesterase activity. HPLC-ESI-MS/MS analysis was performed and twenty-eight phenolic compounds were identified. Regarding the pharmacological activity, better results were observed for the ethyl acetate fraction of E. brevistyla, E. catharinae and especially E. mattosii. Chemical and pharmacological aspects of seasonal E. mattosii extracts were evaluated. The winter leaves extract was the most effective for AChE, and the spring leaves extract was the most effective for BuChE. Correlating the pharmacological results with the chemical data, it was possible to associate these effects to isoquercitrin, quercetin, catechin, epicatechin, procatecuic acid, and myricitrin presence.

Electroanalysis, 2019

A novel silsesquioxane material was synthetized and used as a stabilizing agent for silver nanopa... more A novel silsesquioxane material was synthetized and used as a stabilizing agent for silver nanoparticles. This hybrid material was characterized by FTIR, 29 Si CP-MAS NMR, 13 C DEPT 135°NMR and TGA techniques and the silver nanoparticles were characterized from DLS, UV-Vis spectroscopy, zeta-potential, TEM and SAXS results. The silver nanoparticles obtained were spherical in shape with a diameter of 3.74 nm. The nanomaterial was successfully applied in the modification of a glassy carbon electrode and a pronounced current response was obtained in the determination of the biomarker 4-nitrophenol. Quantum chemical calculations, using density functional theory, were also performed in order to evaluate the redox properties of the analyte. Two different linear ranges were obtained applying optimal square wave voltammetry conditions. The reduction peak currents obtained were linear for 4-NP concentrations in the ranges of 0.29 to 1.50 μmol L À 1 (E d = À 0.6 V and t d = 20 s) and 2.75 to 31.5 μmol L À 1 , with a theoretical (signal to noise = 3) limit of detection of 0.05 μmol L À 1 (t d = 20 s). The proposed method was successfully applied to the determination of 4-NP in synthetic serum samples at different levels of 4-NP with a recovery range of 94-101 %. Validation was performed using a comparative method through the capillary electrophoresis (CE) technique.

Journal of Ethnopharmacology, 2019

ETHNOPHARMACOLOGICAL RELEVANCE Bauhinia forficata Link, commonly known as "cow's paw&quo... more ETHNOPHARMACOLOGICAL RELEVANCE Bauhinia forficata Link, commonly known as "cow's paw", is a native plant from South America. Its leaves are widely used in Brazilian folk medicine to treat diabetes and cardiovascular disorders. Although this species' biological potential has been extensively proven as an antidiabetic, anti-inflammatory and antioxidant agent, there is a lack of studies to evidence its action on the cardiovascular system. AIM OF THE STUDY This study was designed to investigate the vascular effects of B. forficata leaves preparations and its majority compound kaempferitrin, as well as its aglycone form kaempferol, in rat aortic rings of normotensive (NTR) and hypertensive (SHR) rats. MATERIALS AND METHODS Aorta rings from NTR and SHR precontracted with phenylephrine were exposed to cumulative concentrations of B. forficata extract, fractions (1-50 μg/mL) and compounds (0.001-0.3 μg/mL). The mechanisms involved in the vasorelaxant effect of ethyl-acetate plus butanol fraction (EAButF) were also evaluated. RESULTS Although kaempferitrin is the most abundant compound found in both methanolic extract and EAButF, 24 minor phenolic compounds were identified in B. forficata leaves, including kaempferol. EAButF was the only with endothelium-dependent and independent vasorelaxant properties in both NTR and SHR. The incubation with L-NAME or ODQ completely blocked EAButF-induced vasorelaxation. On the other hand, the incubation with propranolol, atropine, indomethacin, glibenclamide or barium chloride did not change the vasorelaxant activity of EAButF (50 μg/mL). Nevertheless, the incubation with tetraethylammonium and 4-aminopyridine significantly influenced the EAButF activity. It was also shown that Ca2+ influx or efflux is not related to EAButF vasorelaxation potential. Kaempferitrin and kaempferol were also able to relax the rat aortic rings in 34.70% and 40.54%, respectively. CONCLUSIONS This study shows, for the first time, the vasorelaxant effect of EAButF from B. forficata leaves, an effect that may be attributed to the modulation of vascular tone through nitric oxide/soluble guanylate cyclase pathway, and potassium channels. The bioactive kaempferitrin and kaempferol seem to be important for the effects observed with the fraction. Finally, preparations obtained from the leaves of B. forficata may be interesting candidates for new or complementary strategies regarding cardiovascular diseases.

Revista Virtual de Química, 2019

The aim of this study was to evaluate the biological potential of the crude hydroalcoholic extrac... more The aim of this study was to evaluate the biological potential of the crude hydroalcoholic extract (EBH) and fractions (FAcOEt and FBuOH) from the roots of Dioscorea scabra. The EBH and its fractions were submitted to antimicrobial activity tests against bacteria with and without cell-wall, and yeasts from the Candida genus. The phytochemical profile of EBH was determined by colorimetric assays and analysis by HPLC in comparison to standard diosgenin. Phytochemical analysis showed the presence of phenols, tannins, flavonoids, xanthones, catechins, steroids, free triterpenoids and saponins, characteristics of the genus. By HPLC analysis, it was possible to identify the presence of diosgenin in the analysed extract. The species was active against all tested bacterial strains, being FBuOH the most active against Mycoplasma arginini species. In the antifungal activity test, samples showed activity against Candida albicans, C. parapsilosis and C. glabrata, with the EBH and FBuOH showing the best results.

Microchemical Journal, 2019

Several restorers of paintings have reported the sensitivity of oil paints toward polar solvents ... more Several restorers of paintings have reported the sensitivity of oil paints toward polar solvents during the chemical cleaning of the surface of the pictorial layer. In this study, a novel mechanism for this phenomenon is described based on the chemical analysis of the pictorial layer of a nineteenth century painting and the swab used in the cleaning of this layer. The pigments used were characterized by FTIR and SEM-EDS and the presence of kaolinite, aclay mineral, was observed in all areas that showed sensitivity. The binder was characterized by GC-MS as a mixture of linseed and walnut oils. SEM analysis showed the presence of pigments adhered to the cotton as well as the presence of kaolinite. GC-MS results for the swab showed the absence of oil in the paint traces present.Thus, the oil and its degradation products are not sensitive toward the polar solvent, but only the pigmentand the kaolinite. Since kaolinite is hygroscopic, it aids the leaching of the pigment of the oil layer onto the swab containing the polar solvent.

Natural Product Research, 2019

Alzheimer's disease and diabetes mellitus are contemporary diseases of great concern. Phenolic co... more Alzheimer's disease and diabetes mellitus are contemporary diseases of great concern. Phenolic compounds are linked to several health benefits and could lead to novel strategies to combat these ailments. The objective of this study was to evaluate by electrophoretically-mediated microanalysis the potential inhibitory activity of the fruit juices from Plinia cauliflora ("jaboticaba") and Eugenia uniflora ("pitanga") toward acetylcholinesterase (AChE) and α-glucosidase, target enzymes in strategies for the treatment of these diseases. The phenolic profiles of the samples were also investigated. Jaboticaba and pitanga juices

Metabolic Brain Disease, 2018

This work investigated the antioxidant and antidepressant-like effects of ethyl acetate extract f... more This work investigated the antioxidant and antidepressant-like effects of ethyl acetate extract from Eugenia catharinensis in mice treated with corticosterone (20 mg/Kg). The animals received saline or corticosterone (21 days) and, in the last 7 days, they were treated with the extract (50, 125, 200 or 250 mg/Kg) or vehicle. After 24 h, the mice were submitted to the open field and forced swimming tests, after which the hippocampus and cerebral cortex were removed. Our results showed that the extract decreased the immobility time of mice in the forced swimming test and that the extract was able to reverse the effect caused by corticosterone. Corticosterone pre-treatment generated oxidative stress, altering antioxidant enzymes in the nervous tissue. The extract increased the catalase and superoxide dismutase activities and reversed the effects of corticosterone. In the hippocampus, the extract increased superoxide dismutase activity and reversed the increase in catalase activity elicited by corticosterone. We propose that the effects elicited by the Eugenia catharinensis are dependent on the presence of phenolic compounds (gallic acid, protocatechuic acid, syringic acid, 4-hydroxy methylbenzoic acid, chlorogenic acid, salicylic acid, caffeic acid, vanillic acid, pcoumaric acid, isoquercetin, rutin, ferulic acid, aromadendrin, galangin and apigenin) in this extract, as demonstrated by HPLC-ESI-MS/MS.

Journal of ethnopharmacology, Jan 10, 2018

Eugenia brasiliensis Lam. (Myrtaceae) is a Brazilian tree distributed throughout Atlantic rain fo... more Eugenia brasiliensis Lam. (Myrtaceae) is a Brazilian tree distributed throughout Atlantic rain forest, since Bahia until Santa Catarina state, and is popularly known as "grumixaba, grumixameira, cumbixaba, ibaporoiti, and cereja-brasileira". The bark and leaves of Eugenia brasiliensis are used in folk medicine as adstringent, diuretic, energizing, anti-rheumatic and anti-inflammatory. This study aimed at investigating the chemical composition, antinociceptive and anti-inflammatory effect of the hydroalcoholic extract of Eugenia brasiliensis (HEEb). Chemical composition of the HEEb was determined by High Performance Liquid Chromatography/ESI-Mass Spectrometry (HPLC-ESI-MS/MS). The antinociceptive and anti-inflammatory effects of HEEb (30-300 mg/kg) was verified in mice after oral administration by intra-gastric gavage (i.g.) 60 min prior to experimentation. It was investigated whether HEEb decreases visceral pain and leukocyte migration induced by an intraperitoneal (i.p.) ...

Natural Product Research, 2017

Abstract This study evaluates the antidepressant-like effect and analysed the qualitative and qua... more Abstract This study evaluates the antidepressant-like effect and analysed the qualitative and quantitative 74 phenolic standards of ethyl acetate fraction from Tabernaemontana catharinensis leaves. Acute administration of fraction in mice reduced the immobility time in forced swimming and tail suspension tests confirming its antidepressant-like activity. The anti-immobility effect elicited by this fraction was prevented by the pretreatment of mice with PCPA (100 mg kg−1), ketanserin (5 mg kg−1), SCH 23,390 (0.05 mg kg−1) or yohimbine (1 mg kg−1). A sub effective dose of the fraction produced a synergistic effect with fluoxetine (5 mg kg−1). Chromatographic analysis identified 4-hydroxybenzoic and p-coumaric acids in the ethyl acetate fraction from T. catharinensis. Capillary electrophoresis presented 7.34 ± 0.02 mg g−1 of p-coumaric acid concentration in the fraction. Therefore, it is possible that antidepressant-like effect elicited by ethyl acetate fraction from T. catharinensis be dependent on the p-coumaric acid.

Revista Brasileira de Farmacognosia, 2017

Eugenia brasiliensis Lam., Myrtaceae, is used in folk medicine for anti-inflammatory diseases suc... more Eugenia brasiliensis Lam., Myrtaceae, is used in folk medicine for anti-inflammatory diseases such as arthritis and rheumatism. This study investigated the anti-inflammatory activity and phenolic profile of the crude hydroalcoholic extract and ethyl acetate fraction from E. brasiliensis leaves. Crude hydroalcoholic extract and the ethyl acetate fraction were analyzed by HPLC-ESI-MS/MS in comparison to standard phenolic compounds. The anti-inflammatory activity of the crude hydroalcoholic extract (1, 10 and 25 mg kg −1) and the ethyl acetate fraction (10, 25 and 50 mg kg −1) was evaluated in a swiss mouse model of acute pleurisy induced by carrageenan, being the total cell count, exudation and analysis of nitrite/nitrate the inflammation parameters. HPLC-ESI-MS/MS analysis revealed apigenin, catechin, galangin, isoquercetin, myricetin, quercetin and rutin. Crude hydroalcoholic extract and ethyl acetate fraction were effective in inhibiting cell migration in all tested doses. Crude hydroalcoholic extract was effective in inhibiting exudation only at the 10 mg kg −1 dose; ethyl acetate fraction was effective in all tested doses. Results for nitrite/nitrate levels reveals that only the ethyl acetate fraction was effective at the tested doses. This is the first report of the presence of isoquercetin, galangin and apigenin in this species. Results from the phytochemical analysis enhance the chemical knowledge of this species. In the future, together with more studies, validation of its popular use in inflammatory diseases is possible.

Natural Product Research, 2015

Preservatives used in the food industry are undergoing increasing scrutiny and reappraisal. There... more Preservatives used in the food industry are undergoing increasing scrutiny and reappraisal. There is therefore a renewed interest in the antimicrobial properties of herbs and spices. Rosemary (Rosmarinus officinalis L.) belonging to the Lamiaceae family, is a pleasant-smelling perennial herb. The antimicrobial activities of the R. officinalis oil against Leuconostoc mesenteroides (PTCC1591), Lactobacillus delbruekii (PTCC1333), Saccharomyces cerevisia (PTCC5269) and Candida krusei (PTCC 5295) were determined. The results indicate that among the tested microbes, the essential oil had a stronger inhibitory effect on the bacteria as compared to yeasts. Minimum inhibitory concentration (MIC) values for bacteria L. mesenteroides, L. delbruekii, S. cerevisia and C. krusei ranged between 0.5 and 1.5 mg/ml. The oil was analyzed by GC and GC/MS. The major components of R. officinalis oil were 1,8-cineole (23.14%), camphor (12.35%), α-pinene (9.87%), β-pinene (6.10%), borneol (5.61%), camphene (5.58%) and α-terpineol (4.30%), respectively. These results indicate the latent potency of essential oil of R. officinalis as a natural preservative in food products against L. mesenteroides, L. delbruekii, S. cerevisia and C.krusei.

Natural Product Research, 2014

This study describes the seasonal composition and the antibacterial, antioxidant and anticholines... more This study describes the seasonal composition and the antibacterial, antioxidant and anticholinesterase activity of the essential oil from Eugenia brasiliensis leaves. Analysis by using GC allowed the identification of 40 compounds. It was observed that the monoterpenes varied more (42%) than the sesquiterpenes (14%), and that the monoterpene hydrocarbons suffered the greatest variation throughout the year (64%). Major compounds were spathulenol in the spring (16.02 ± 0.44%) and summer (18.17 ± 0.41%), τ-cadinol in the autumn (12.83 ± 0.03%) and α-pinene (15.94 ± 0.58%) in the winter. Essential oils were tested for their antibacterial activity, and the best result was obtained from the autumn oil, with MIC = 500 μg mL(- 1) against Staphylococcus saprophyticus and Pseudomonas aeruginosa. Antioxidant activity was evaluated using DPPH, lipid peroxidation and iron-reducing power assays, as well as the anticholinesterase activity. Both tests showed a weak performance of the essential oils.

International Journal of Clinical Medicine, 2014

Background: Diabetes Mellitus (DM) is one of the major health problems and morbidity causes in co... more Background: Diabetes Mellitus (DM) is one of the major health problems and morbidity causes in contemporary society worldwide. Recently, it has been suggested that the addition of citrate in plasma extraction decreases glucose degradation by endogenous enzymes, which could contribute in an important manner to the diagnosis of DM. However, this strategy has not been sufficiently evaluated. The present study aimed to evaluate glucose determination in serum and in plasma obtained with different anticoagulants. Methods: We obtained 20 venous blood paired samples on consecutive days from the same individual, collected in dry tubes with separator gel and in glass tubes with sodium fluoride and EDTA-K2, either in the presence or absence of sodium citrate. Glucose was determined by an oxidase/peroxidase method using the same system by a unique analyst. Results: Serum determinations were constantly higher than in plasma (P < 0.02), and the addition of citrate increased the analytical variability. Conclusions: Our results were highly relevant statistically, and did not corroborate the addition of citrate in plasma extraction for the inhibition of glycolysis, at least using the standard anticoagulant concentrations.

Applied Biochemistry and Biotechnology, 2020

The studies on natural compounds to diabetes mellitus treatment have been increasing in recent ye... more The studies on natural compounds to diabetes mellitus treatment have been increasing in recent years. Research suggests that natural components can inhibit alpha-glucosidase activities, an important strategy in the management of blood glucose levels. In this work, for the first time in the literature, the compounds produced by Ganoderma lipsiense extracts were identified and evaluated on the inhibitory effect of these on alphaglucosidase activity. Four phenolic compounds were identified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) to crude extract from G. lipsiense grown in red rice medium (RCE) and synthetic medium (SCE), being syringic acid identified in both extracts. Gas chromatography-mass spectrometry (GC-MS) analysis showed fatty acids and their derivatives, terpene, steroid, niacin, and nitrogen compounds to SCE, while RCE was rich in fatty acids and their derivatives. Both extracts demonstrated alpha-glucosidase inhibition (RCE IC 50 = 0.269 ± 8.25 mg mL −1 ; SCE IC 50 = 0.218 ± 9.67 mg mL −1), and the purified hexane fraction of RCE (RHEX) demonstrated the highest inhibition of enzyme (81.1%). Studies on kinetic inhibition showed competitive inhibition mode to RCE, while SCE showed uncompetitive inhibition mode. Although the inhibitory effects of RCE and SCE were satisfactory, the present findings identified some unpublished compounds to G. lipsiense in the literature with important therapeutic properties.