The Evaluation of Stachys lavandulifolia Leave Extracts on Cysts of G. Lamblia , in Vitro

Background: Diarrheal disease is one of the most common problems that affected deployed military personnel during operations and maneuvers. Giardia (G.) lamblia is one of the causes of parasitic diarrhea in humans. There are very few therapeutics agents with unpleasant adverse effects available for treating giardiasis. Stachys lavandulifolia with polyphenolic structure is considered as an antimicrobial agent. In this study we evaluated the in vitro inhibitory activity of Stachys lavandulifolia leaves on cysts of G. lamblia. Methods: G. lamblia cysts were isolated by the sucrose method. Various concentrations of the watery and n-hexane extracts (2.5, 5, 10, 25, 50 mg/mL respectively) were used for giardiacidal activity in 6 different times (1, 5, and 30 minutes, as well as 1, 3, and 6 hours). Results: The watery and n-hexane extract revealed great activity when compared to the control group (P < 0.05). The watery extract at the concentration of 100 mg/mL killed 93% of cysts after 6 hours. The n-hexane extract at the concentration of 100 mg/mL killed 100% of cysts after 6 hours. Both extracts showed dose dependent antigiardial activity and the n-hexane extract was better than the watery extract. When the doses of the extracts and contact times are increased, a gradual increase in antiprotozoal activity was observed. Conclusions: Stachys lavandulifolia leaves, as a safe herbal medicine could be confirmed for anti giardial activity.