Effects of Volatile Oil from the Leaves of Clausena Anisata Hook. on Smooth Muscle Contractions

Abstract

Preliminary study of the pharmacological action of volatile oil from the leaves of

Clausena anisata Hook. was carried out in various smooth muscle preparations. Cumulative

doses of the essential oil (5x10^-5 - 3.2x10^-3 % v/v) stimulated the contractile response of all

smooth muscle preparations. The highest stimulation was found in isolated rat aorta (47.03 %,

EC50 = 1.28x10^-2 %). The others were guinea-pig ileum (39.40 %, EC50 = 9.6x10^-3 %) rat

fundus (26.19 %, EC50 = 8.192x10^-1 %) guinea-pig trachea (15.78 %) and rabbit jejunum

(4.99 %). These spasmodic effects were investigated through autonomic nervous system. The

result demonstrated that atropine was not able to attentuate the stimulation effect of the

essential oil on the isolated rabbit jejunum and guinea-pig ileum while the inhibitory effects

of atropine (1x10^-7 and 1x10^-6 M) were prominently found in the contraction induced by the

essential oil on rat fundus. Relaxation effect was insignificantly shown in guinea-pig trachea

after exposure to atropine. Sympathetic mechanism of the essential oil was confirmed in rat

aorta since prazocin ( 1x10^-7 M) reduced the contractile response, produced by the essential

oil, significantly. Furthermore, inhibition of extracellular calcium ion through calcium

channel was shown in the essential oil induced smooth muscle contraction in calcium free

Krebs Henseleit solution and after verapamil exposure. All these results could be concluded

that the essential oil from the leaves of Clausena anisata possessed smooth muscle

stimulation effect partly through sympathetic and parasympathetic mechanisms.