RESUMO
Solvent extracts of ginger, the rhizome of Zingiber officinale Roscoe (Zingiberaceae), have been extensively studied for their pharmacological activities in smooth muscles. However, the effects of ginger essential oil on smooth muscle contractility have not been elucidated. The aims of the study were to investigate the effects of ginger oil on rat myometrial contractility. We particularly examined the effects on phasic contractions arising either spontaneously or with PGF (2) (alpha) stimulation. Ginger oil was obtained by hydrodistillation and its constituents analyzed using gas chromatography and mass spectrometry. Rats were humanely killed by asphyxiation with CO (2), and longitudinal uterine smooth muscles were isolated. Isometric force was measured and the effects of ginger oil studied. It was found that citral was the main constituent of ginger oil (24 %). Ginger oil inhibited spontaneous contractions with an IC (50) of 50 microL/100 mL (10 - 150 microL/100 mL). The PGF (2) (alpha)-induced contractions were also significantly reduced by ginger oil. Increases in external calcium concentration completely reversed the relaxant effects of ginger oil. This was the case for both spontaneous and PGF (2) (alpha)-induced contractions. The effects of ginger oil were indistinguishable from those of pure citral. In conclusion, ginger oil is a potent inhibitor of phasic activity in rat uterus, irrespective of how it was produced. Our data suggest that the effects are largely due to citral, and could be via inhibition of L-type Ca channels.
Assuntos
Dinoprosta/farmacologia , Contração Muscular/efeitos dos fármacos , Miométrio/efeitos dos fármacos , Óleos de Plantas/farmacologia , Zingiber officinale/química , Monoterpenos Acíclicos , Animais , Feminino , Monoterpenos/farmacologia , Miométrio/fisiologia , Fármacos Neuromusculares/farmacologia , Nifedipino/farmacologia , Óleos de Plantas/química , Ratos , Ratos Endogâmicos WF , Vasodilatadores/farmacologiaRESUMO
Chitinase cDNAs from Leucaena leucocephala seedlings were cloned by PCR amplification with degenerate primers based on conserved class I chitinase sequences and cDNA library screening. Two closely related chitinase cDNAs were sequenced and inferred to encode precursor proteins of 323 (KB1) and 326 (KB2) amino acids. Expression of the KB2 chitinase from a pET32a plasmid in Origami (DE3) Escherichia coli produced high chitinase activity in the cell lysate. The recombinant thioredoxin fusion protein was purified and cleaved to yield a 32-kDa chitinase. The recombinant chitinase hydrolyzed colloidal chitin with endochitinase-type activity. It also inhibited growth of 13 of the 14 fungal strains tested.