Paulo Roberto da Silva Ribeiro

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Amburana cearensis (Fr. Allem) AC Smith is a native Caatinga species commonly found in the semiarid region of North East of Brazil, which possesses resistance to temperature and drought stress and is widely used in the folk medicine. This study aimed at a better understanding of seed imbibition and germination as well as to evaluate the effect of water(More)
BACKGROUND Schinus terebinthifolius is widely used in traditional medicine by Brazilian quilombola and indigenous communities for treatment of several diseases. Extracts from different tissues are being used to produce creams to treat cervicitis and cervicovaginitis. However, most studies are limited to the assessment of the essential oils and extracts(More)
Cocrystals represent a class of crystalline solids consisting of two or more molecular species usually held together by non-covalent bonds. Pharmaceutical cocrystals can alter the physicochemical properties of the active pharmaceutical ingredient to improve solubility, dissolution rate, particle properties and stability. This work presents a process(More)
A flow-injection spectrophotometric procedure is proposed for methyldopa determination in pharmaceutical preparations. The determination is based on formation of a yellow product (measured at 410nm) after complexation of methyldopa with molybdate. Under optimal conditions, Beer's law is obeyed in a concentration range of 50-200mgl(-1) methyldopa. Typical(More)
Phytochemical investigation on Clusia burlemarxii (Clusiaceae) led to isolation and identification of nine compounds. Were isolated from leaves 3-O-α-L- rhamnopyranosylquercetin, 3-O-α-L-rhamnopyranosylkaempferol, 4-hydroxy-5,5-dimethyldihydrofuran-2-one, 2Z-δ-tocotrienoloic acid and friedelin and were isolated from trunk betulinic acid, protocatechuic(More)
Captopril, chemically know as 1-[(2S)-3mercapto-2-methylpropionyl]-L-proline, (CPT) is used therapeutically as an antihypertensive agent [11, 15], which is also prescribed for the treatment of congestive hart failure [6]. Several types of analytical procedures have been proposed for the analysis of captopril in pharmaceuticals formulations. These procedures(More)
Cocrystals are defined as crystalline structures composed of two or more compounds that are solid at room temperature held together by noncovalent bonds. Their main advantages are the increase of solubility, bioavailability, permeability, stability, and at the same time retaining active pharmaceutical ingredient bioactivity. The cocrystallization between(More)
Jatropha curcas is an oilseed crop renowned for its tolerance to a diverse range of environmental stresses. In Brazil, this species is grown in semiarid regions where crop establishment requires a better understanding of the mechanisms underlying appropriate seed, seedling and plant behaviour under water restriction conditions. In this context, the(More)
A study was performed to evaluate the environmental contamination in the Turvo Limpo River basin which receives effluent discharges from domestic (residential and commercial) activities. The watercourses examined were the São Bartolomeu Stream, Turvo Sujo River, and Turvo Limpo River, located in the Minas Gerais State, Brazil. Water samples were collected(More)
The production of propolis by honeybees results from a selective collection of exudates from various plant species and present many potentialities in the pharmaceutical industry. The objective of this study was to investigate the chemical profile of Brazilian propolis, as well as their in vitro antioxidant and antibacterial activities. Gas(More)