Spasmolytic and antidiarrheal activities of Lippia thymoides (Verbenaceae) essential oil.

Lippia thymoides ('alecrim-do-mato' or 'alecrim-do-campo') is used in Brazilian folk medicine to treat various illnesses, including diarrhea. This work aimed to evaluate in vitro spasmolytic and in vivo antidiarrheal activities of the L. thymoides essential oil (OOS) and to correlate with the traditional use of this plant. In isolated guinea-pig ileum, OOS presented a concentration-dependent spasmolytic activity in preparations pre-contracted with KCl 40 mM [EC50  = 16.89 (11.56-24.66) μg/mL], and antagonized phasic contractions induced by 1 μM carbachol [IC50  = 42.71 (37.35-48.83) μg/mL] or histamine [IC50  = 32.38 (27.44-38.20) μg/mL]. In mice, OOS at 400 mg/kg reduced intestinal transit, at 200 and 400 mg/kg reduced total stool mass and at 400 mg/kg reduced intestinal fluid accumulation. It was shown that the antidiarrheal effect of OOS is related to the inhibition of smooth muscle contraction and may be due to the presence of major compound β-caryophyllene in this essential oil.