Linked Life Data

12715086

Source:http://linkedlifedata.com/resource/pubmed/id/12715086

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2003-4-25
pubmed:abstractText
Many pharmacological effects have been ascribed to extracts of Psidium guajava L. (guava) leaves. However, in spite of its widespread use in Brazilian folk medicine and a reasonable number of scientific reports about it, we could not find any study dealing with its action on the mammalian myocardium. In the present study, by measuring isometric force, we observed that the crude extract of P. guajava (water-alcohol extract obtained by macerating dry leaves) depresses the guinea pig atrial contractility in a concentration-dependent fashion (N = 8 hearts, 15 trials). The compound with cardiac activity was concentrated by extraction in a Soxhlet apparatus using 17 M glacial acetic acid after removing the less polar fractions (hexane, chloroform, acetone, ethanol and methanol), suggesting that this compound is a highly polar substance. In the isolated guinea pig left atrium the acetic acid fraction (10-800 mg/l) of P. guajava 1) reversibly decreased myocardial force in a concentration-dependent fashion (EC50 = 0.07g/l, N = 5 hearts, 9 trials, P<0.05), 2) increased the atrial relaxation time measured at 20% of the force amplitude up to 35% (91 +/- 15 to 123 +/- 30 ms, N = 3 hearts, 6 trials, P<0.05), 3) abolished the positive staircase effect (Bowditch phenomenon) in a concentration-dependent fashion suggesting a decrease of the cellular inward calcium current (N = 4 hearts, 8 trials, P<0.05), and 4) its inotropic effect was abolished by cholinergic receptor blockade with 1.5 mM atropine sulfate, indicating a cholinergic involvement in the mechanism of action of the extract (N = 7 hearts, 15 trials, P<0.05). The acetic acid extract was 20 times more potent than crude extract (EC50 = 1.4 g/l). The results showed that extracts from P. guajava leaves depress myocardial inotropism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0100-879X
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
661-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Inotropic effects of extracts of Psidium guajava L. (guava) leaves on the guinea pig atrium.
pubmed:affiliation
Laboratório de Biofísica dos Tecidos Excitáveis, Departamento de Fisiologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil. egarcia@ufs.br
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't