Effect of Piper betle on Giardia intestinalis infection in vivo.

Piper betle has been used as a medicinal plant in traditional medical systems throughout South and South East Asia. Experimental studies have revealed its wide and diverse biological and pharmacological effects. In this study, antigiardial activity of Piper betle was tested using experimental infections of Giardia intestinalis, the most common cause of protozoal diarrhoea worldwide, in Mongolian gerbils. Plants were extracted in water, methanol and methanol:tetrahydrofuran. Gerbils were treated for ten days intragastrically twice a day, with the dose of 40 mg of the extract per 100 g of body weight. Drug metronidazole was used as a negative control. Gerbils' faeces were taken every day and examined by flotation method, the number of shed cysts were counted using a haemocytometer. After gerbils' sacrifice and dissection, their duodena were then processed for examination using histological sectioning and scanning electron microscopy. The antigiardial activity was evaluated by the course of cyst shedding throughout the entire experiment. A significant decline in cyst shedding, evaluated by linear regression was found in gerbils treated with the aqueous extract. Our results indicate that the aqueous extract of P. betle shows giardicidal effects.