ABSTRACT
A espécie Pereskia grandifolia Haworth (Cactaceae), conhecida popularmente como ora-pro-nóbis, foi avaliada quanto às suas propriedades antioxidantes e susceptibilidade antimicrobiana. As propriedades antioxidantes foram avaliadas pelo método de inibição do radical livre 2,2-difenil-1-picrilidrazil (DPPH?). Os extratos das folhas de P. grandifolia (1000 ?g/mL) apresentaram propriedades antioxidantes entre 10 e 30% de inibição. Dentre os extratos avaliados, o diclorometânico e o acetato de etila apresentaram maior capacidade de seqüestro de radicais livres de DPPH' (25 e 30% de inibição, respectivamente). A susceptibilidade antimicrobiana foi avaliada pelo método de microdiluição. Não se observau atividade antibacteriana frente a Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623) e Pseudomonas aeruginosa (ATCC 27853), nem atividade antifúngica frente a Candida albicans (ATCC 10231).
The specie Pereskia grandifolia Haworth (Cactaceae), popularly known as ora-pro-nóbis, was evaluated for their antioxidant property and antibacterial susceptibility. The antioxidant properties were evaluated by inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The P. grandifolia leaves extracts (1000 μg/mL) shown antioxidant properties, with inhibition varying between 10 and 30% of control. Among the tested extracts, the dichloromethane and ethyl acetate extracts presented higher free radicals scavenging capability in the DPPH method (25 and 30% of inhibition, respectively). Antibacterial activity was not observed against the Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623) and Pseudomonas aeruginosa (ATCC 27853), neither antifungal activity against Candida albicans (ATCC 10231).
Subject(s)
Cactaceae , Anti-Infective Agents , AntioxidantsABSTRACT
In utero, blood shunts away from the lungs via the ductus arteriosus (DA) and the foramen ovale. After birth, the DA closes concomitant with increased oxygen tension. The present experimental series tests the hypothesis that oxygen directly increases DA smooth muscle cell (SMC) cytosolic calcium ([Ca(2+)](i)) through inactivation of a K(+) channel, membrane depolarization, and entry of extracellular calcium. To test the hypothesis, DA SMC were isolated from late-gestation fetal lambs and grown to subconfluence in primary culture in low oxygen tension (25 Torr). DA SMC were loaded with the calcium-sensitive fluorophore fura-2 under low oxygen tension conditions and studied using microfluorimetry while oxygen tension was acutely increased (120 Torr). An acute increase in oxygen tension progressively increased DA SMC [Ca(2+)](i) by 11.7 +/- 1.4% over 40 min. The effect of acute normoxia on DA SMC [Ca(2+)](i) was mimicked by pharmacological blockade of the voltage-sensitive K(+) channel. Neither removal of extracellular calcium nor voltage-operated calcium channel blockade prevented the initial increase in DA SMC [Ca(2+)](i). Manganese quenching experiments demonstrated that acute normoxia initially decreases the rate of extracellular calcium entry. Pharmacological blockade of inositol triphosphate-sensitive, but not ryanodine-sensitive, intracellular calcium stores prevented the oxygen-induced increase in [Ca(2+)](i). Endothelin increased [Ca(2+)](i) in acutely normoxic, but not hypoxic, DA SMC. Thus acute normoxia 1) increases DA SMC [Ca(2+)](i) via release of calcium from intracellular calcium stores, and subsequent entry of extracellular calcium, and 2) potentiates the effect of contractile agonists. Prolonged patency of the DA may result from disordered intracellular calcium homeostasis.
