Inhibitory effects of ginger oil on spontaneous and PGF2alpha-induced contraction of rat myometrium.
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.
Buddhakala
Nopparat
N
Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand.
Talubmook
Chusri
C
Sriyotha
Poonsook
P
Wray
Susan
S
Kupittayanant
Sajeera
S
D000080462:Acyclic Monoterpenes; D000818:Animals; D015237:Dinoprost / Q000494:pharmacology*; D005260:Female; D020939:Zingiber officinale / Q000737:chemistry*; D039821:Monoterpenes / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D009465:Neuromuscular Agents / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D011920:Rats, Inbred WF; D014665:Vasodilator Agents / Q000494:pharmacology
D000080462:Acyclic Monoterpenes; D039821:Monoterpenes; D009465:Neuromuscular Agents; D010938:Plant Oils; D014665:Vasodilator Agents; D015237:Dinoprost; D009543:Nifedipine; C007076:citral