Virginia Claudia da Silva

Chemical constituents from leaves of Palicourea coriacea (Rubiaceae)

Abstract(E)-Methyl-4-hydroxy-3,5-dimethoxycinnamate, (E)-methyl-4-hydroxy-3-methoxycinnamate, (E)-methyl-4-hydroxycinnamate, (Z)-methyl-4-hydroxycinnamate, calycanthine, ursolic acid, 2-hydroxy-3-methylanthraquinone, 4-methoxybenzoic acid, 3,4,5-trimethoxybenzoic acid, methyl 4-hydroxybenzoate and allantoin were isolated from the leaves of Palicourea coriacea (Cham.) K. Schum. The structures were deduced by spectral data analysis and comparison with literature values.

Atividade anti-helmíntica dos flavonóides isolados das raízes de Andira anthelmia (Leguminosae)

Bioactivity-guided fractions of the methanol extract from the roots of Andira anthelmia led the isolation of the isoflavones biochanin A and genistein from the ethyl acetate fraction; biochanin A 7-O-β-D-glucopyranoside, biochanin A 7-O-α-L-rhamnopyranosyl-(1→6)β-D-glucopyranoside and biochanin A 7-O-β-D-apiofuranosyl-(1→5)-β-D-apiofuranosyl-(1→6)β-D-glucopyranoside from the n-butanol fraction and catechin from the methanol one. Their structures were elucidated on the basis of spectroscopy data. The anthelmintic activity was investigated in mice naturally infected by Aspiculuris tetraptera. The compounds administered in the animals by intragastric route in doses of 2.0 mg.kg-1, were effective in the removal of the total number of the A. tetraptera when compared with the control group.

6-acetonyl-N-methyl-dihydrodecarine, a new alkaloid from Zanthoxylum riedelianum

A new benzophenanthridine alkaloid, 6-acetonyl-N-methyl-dihydrodecarine was isolated from Zanthoxylum riedelianum roots together with lupeol, 6-acetonyldihydrochelerythrine and 6-acetonyldihydroavicine. The structures were established from the IR, MS and NMR spectral data, including 2D-NMR experiments.

Estudo fitoquímico das cascas das raízes de Zanthoxylum rigidum Humb. & Bonpl. ex Willd (Rutaceae)

Chemical investigation from root barks of Z. rigidum, resulted in the isolation of lupeol, a mixture of steroids campesterol, sitosterol, stigmasterol, sacarose, hesperidin, N-methylatanine and 6-acetonyldihydrochelerythrine. Their structures were established by spectral data analysis. No previous work has been reported on Z. rigidum species.

Combretum lanceolatum flowers extract shows antidiabetic activity through activation of AMPK by quercetin

The present study evaluated the antidiabetic activity of the Combretum lanceolatum Pohl ex Eichler, Combretaceae, flowers extract (ClEtOH) in diabetic rats. Streptozotocin-diabetic rats were divided into four groups: diabetic control, diabetic treated with 500 mg/kg of metformin and diabetic treated with 250 or 500 mg/kg of ClEtOH for 21 days. The treatment of diabetic rats with 500 mg/kg of ClEtOH promoted an increase in the weight of liver, white adipose tissues and skeletal muscles, improving body weight gain. Diabetic rats treated with 500 mg/kg of ClEtOH also presented reduction in glycemia, glycosuria and urinary urea levels, and increase in liver glycogen content. HPLC chromatogram showed that quercetin is the major compound in the extract. The phosphorylation levels of adenosine monophosphate-activated protein kinase were increased in liver slices incubated in vitro with 50 µg/mL of ClEtOH, similarly to the incubation with metformin (50 µg/mL) or quercetin (10 µg/mL). The antihyperglycemic effect of ClEtOH was similar to that of metformin and appears to be through inhibition of gluconeogenesis, since urinary urea was reduced and skeletal muscle mass was increased. These data indicate that the antidiabetic activity of the Combretum lanceolatum extract could be mediated, at least in part, through activation of adenosine monophosphateactivated protein kinase by quercetin.

[1-8-NαC]-Zanriorb A1, a Proapoptotic Orbitide from Leaves of Zanthoxylum riedelianum.

A new orbitide named [1-8-NαC]-zanriorb A1 (1) was isolated and characterized from the leaves of Zanthoxylum riedelianum using NMR and mass spectrometry. The absolute configuration of the amino acids was determined using Marfeys method on the acid hydrolysates. Compound 1 induced cell death by apoptosis in Jurkat leukemia T cells (IC50 218 nM).

Urea-assisted fabrication of Fe 3 O 4 @ZnO@Au composites for the catalytic photodegradation of Rhodamine-B

AbstractA new chemical approach for the fabrication of Fe3O4 embedded ZnO magnetic semicondutctor composite is reported. The method consists in increasing the pH of the synthesis solution by the thermal decomposition of urea instead of using common alkaline agents, such as NaOH and NH4OH. The material (Fe3O4@ZnO) was used as a platform for the fabrication of highly dispersed gold nanoparticles (~5 nm). The catalytic efficiency of the material, Fe3O4@ZnO@Au, was tested in the photodegradation of Rhodamine-B solutions, and prominent catalytic efficiency, stability, and recycling were achieved. A single portion of the catalyst could be used up to five times without significant loss of activity and its photodegradation efficiency was considered high even after the 12th cycle (56%). Catalyst separation after each batch could be easily achieved because of the intrinsic magnetic property of the material. Leaching monitoring of free Zn species during the fabrication of the catalyst suggests that the use of urea decreased substantially the formation of non-magnetic-semiconducting species and provided a higher mass yield of the magnetic composite compared to an analogous protocol using NaOH. The catalyst was also characterized by detailed structural and chemical analyses, such as transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and vibration sample magnetometer (VSM).

Chemical constituents and antileukemic activity of Eugenia dysenterica

Abstract The study about Eugenia dysenterica led to the isolation of 3-acetyl-urs-12-en-28-oic (1), 3-acetyl-olean-12-en-28-oic acid (2) and isoquercetin (3) from the stem barks, and of 3-O-β-glucopyranosyl-β-sitosterol (4), methyl 3-hydroxy-4-methoxybenzoate (5), methyl 4-hydroxyphenyl propionate (6), E-methyl-4-hydroxycinnamate (7), quercetin-3-O-(6ꞌꞌ-O-galloyl)-β-d-glucopyranoside (8) and quercetin-3-O-β-d-galactopyranoside (9) from the leaves. The structures 1–9 were set through the analysis of their NMR spectroscopic data. Compounds 2, 3 and 5–8 were reported for the first time in the Eugenia genus. Compound 8 reduced cell viability and presented IC50 values 40.3 and 36.7 μM, for the CCRF-CEM and the Kasumi-1 cells, respectively.

A new dammarane saponin and other triterpenoids from Siolmatra brasiliensis and evaluation of the antidiabetic activity of its extract

Abstract Context Siolmatra brasiliensis (Cogn.) Baill (Cucurbitaceae) is a climbing plant widely used for the treatment of diabetes mellitus symptoms. Objective This work evaluates the antidiabetic activity of an extract of S. brasiliensis in streptozotocin-diabetic rats and promotes the phytochemical investigation to isolate the major compounds of the same extract. Materials and methods Male Wistar rats were divided into normal (N) and diabetic rats (DC) treated with water; diabetic rats treated with 3U insulin (DI) or with 250 (DSb250) or 500 mg/kg (DSb500) of hydroalcoholic extract of the stalks of S. brasiliensis, via oral gavage, for 21 days. Physiological and biochemical parameters classically altered in diabetes were monitored. The triterpenoids were isolated from the ethyl acetate fraction under silica gel column chromatography and Sephadex-LH20 methods and their structures were determined by NMR, HR-ESI-MS and DC analysis. Results When compared with DC, DSb250 rats showed a reduction in the hyperglycemia (DC: 26.46 ± 0.69 versus DSb250: 19.67 ± 1.06 mmol/L) and glycosuria (DC: 43.02 ± 3.19 versus DSb250: 28.46 ± 2.14 mmol/24 h) and increase in hepatic glycogen (DC: 14.44 ± 1.26 versus DSb250: 22.08 ± 4.26 mg/g). Three known cucurbitacins were isolated from a hydroalcoholic extract of S. brasiliensis, i.e., cayaponosides A1, B4, D, and a new dammarane saponin 3-O-β-d-gentiobiosyl-26-O-β-d-glucopyranosyl-20-hydroxydammar-24-ene. The structures of these compounds were elucidated by spectral data analysis of the natural products and their acetyl derivatives. Discussion and conclusion The known cucurbitacins and/or the new identified saponin may be related with the antidiabetic activity of S. brasiliensis.

Estudo Químico das Folhas de Acosmium Dasycarpum (Vogel) Yakovlev

Acosmium dasycarpum e uma planta exclusiva do cerrado. Conhecida como perobinha do campo. Apesar de amplamente utilizada pela populacao para o tratamento de uma serie de enfermidades, pouco se conhece sob o ponto de vista quimico. Neste trabalho apresentamos o isolamento da catequina, lupeol, isomeros (E)-4-hidroxicinamato de metila (A) e (Z)-4-hidroxicinamato de metila (B), bornesitol e 3-O-B-D-glicopiranosilsitosterol, sendo que a excecao do lupeol, os demais compostos isolados sao ineditos nesta especie.