Eugenia sonderiana O. Berg leaves: Phytochemical characterization, evaluation of in vitro and in vivo antidiabetic effects, and structure-activity correlation.

Several medicinal plants have drawn the attention of researchers by its phytochemical composition regarding their potential for treating chronic complications of diabetes mellitus. In this context, plants of the Myrtaceae family popularly used in Brazil for the treatment of diabetes mellitus, including Eugenia sonderiana, have shown beneficial effects due to the presence of phenolic compounds and saponins in their chemical constitution. Thus, the present work aimed to perform the phytochemical characterization of the hydroethanolic extract of E. sonderiana leaves using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS), along with in vitro and in vivo studies of antidiabetic activity. The chemical characterization revealed the presence of phenolic compounds, flavonoids, neolignans, tannins, and saponins. In addition, the extract exhibited minimum inhibitory concentrations of alpha-amylase and alpha-glycosidase higher than the acarbose in the in vitro tests. Also, the in vivo tests revealed a slight increase in body mass in diabetic rats, as well as a significant decrease in water and feed consumption provided by the extract. Regarding serum biochemical parameters, the extract showed significant activity in decreasing the levels of glucose, hepatic enzymes, and triglycerides, in addition to maintaining HDL cholesterol levels within normal ranges, protecting the cell membranes against oxidative damage. Thus, the extract of E. sonderiana leaves was considered promising pharmaceutical ingredient in the production of a phytotherapy medication.

Brazilian Bromeliaceae species: isolation of arylpropanoid acid derivatives and antiradical potential / Espécies de Bromeliaceae Brasileiras: isolamento de derivados arilpropanoídicos e potencial antiradicalar

A total of twenty different extracts from six Brazilian Bromeliaceae species was screened for antioxidant activity by assessment of their capacity to scavenge the DPPH radical. In a general way, the polar rhizome extracts from Bromeliaceae representatives showed better antioxidant results than the extracts from leaves and fruits of the same species. The best results were found for the rhizome extracts of Vriesea procera (Mart. ex Schult.f.) Wittm. and Neoregelia cruenta (Graham) L.B. Sm. Crude methanol extract of Ananas bracteatus (Lindl.) Schult. & Schult. f. leaf had a significant antiradical activity among the leaves extracts assessed its purification afforded four metabolites: 2-O-feruloyl glyceride, 2-O-p-coumaroyl glyceride, 5,7,4'-trihydroxy-3,3',5'-trimethoxyflavone and 3-O-β-D-glucopyranosyl sitosterol.

Um total de vinte extratos de seis espécies de Bromeliaceae brasileiras foram avaliadas quanto a atividade antioxidante, usando-se o método colorimétrico de redução do radical DPPH. De maneira geral, os extratos polares dos rizomas das espécies de Bromeliaceae testadas revelaram melhor perfil antioxidante do que os extratos das folhas e dos frutos das mesmas espécies. Os melhores resultados foram encontrados para os rizomas de Vriesea procera (Mart. ex Schult.f.) Wittm. e Neoregelia cruenta (Graham) L.B. Sm. O extrato bruto metanólico das folhas de Ananas bracteatus (Lindl.) Schult. & Schult. f. apresentou uma atividade significativa, em relação aos extratos de folhas testados, e o processo de purificação desse extrato resultou na identificação de quatro metabólitos: ferulato de 2-glicerila, p-cumarato de 2-glicerila, 5,7,4'-triidroxi-3,3',5'-trimetoxiflavona e 3-O-β-D-glicopiranosil sitosterol.

Comparative studies of the effects of Tabebuia avellanedae bark extract and beta-lapachone on the hematopoietic response of tumour-bearing mice.

The effects of Tabebuia avellanedae (TACE), traditionally prescribed in the treatment of cancer, and the naphtoquinone beta-lapachone (beta-lap) on the growth and differentiation of granulocyte and macrophage progenitor cells (CFU-GM) were studied in Ehrlich ascites tumour-bearing mice. Myelosuppression concomitant with increases in spleen CFU-GM and in serum colony-stimulating activity (CSA) were observed in these animals. Treatment with TACE (30-500 mg/kg) and beta-lap (1-5mg/kg) reversed these effects in a dose-dependent manner. The optimal biologically active doses of 120 mg/kg TACE and 1mg/kg beta-lap prolonged life span of tumour-bearing mice, both producing the same rate of extension in the duration of survival. Toxic manifestations were produced by the higher doses of beta-lap in normal and tumour-bearing mice. In spite of similarities between treatments, TACE concentrations used to treat the animals presented no traces of beta-lap, as measured by TLC and HPLC analyses. Our findings suggest that the antitumour effect of TACE and beta-lap, acting synergistically with other factors, such as specific cytokines, may result from enhanced macrophage activation against tumour cells. In addition, it is clear from our results that hematopoietic disorders produced by tumours are an important pathological condition that must be considered in drug development.

Alpha-amylase inhibitors from Brazilian seaweeds and their hypoglycemic potential.

The acetone crude extract of Lobophora variegata did not show any alpha-amylase inhibition activity. On the contrary, acetone crude extract of both Spatoglossum schroederi and Caulerpa racemosa inhibited the enzyme activity, with an ED(50) of 0.58 and 0.09 mg/ml.