In vitro and in vivo effects of hesperidin treatment on adult worms of Schistosoma mansoni G. Allam 1,2 * and A.S.A. Abuelsaad 1,2 1 Department of Microbiology, College of Medicine, Taif University, Taif, Saudi Arabia: 2 Department of Zoology, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt (Received 15 October 2012; Accepted 22 March 2013; First Published Online 9 May 2013) Abstract Hesperidin has been reported to exert a wide range of pharmacological effects, including antifungal, antiviral, antioxidant, anti-inflammatory and anticarcino- genic activities. Herein, the schistosomicidal activity of this compound was evaluated in vitro and in vivo. Using an in vitro assay, a concentration of 200 mg/ml of hesperidin resulted in the mortality of 100% adult worms of Schistosoma (S.) mansoni within 72 h and a partial tegumental alteration in 10% of worms. However, after 144 h incubation, 50 and 100 mg/ml concentrations showed 0% and 10% mortality in adult worms, respectively, without any changes to the tegument. Sublethal doses did not influence egg output nor the development of eggs deposited by pairs of adult worms. In an in vivo study, mice infected with S. mansoni and treated with 600 mg hesperidin/kg body weight showed a respective reduction of 50, 45.2, 50 and 47.5% of males, females, worm pairs and total worm burden. In addition, a respective reduction, based on the number of eggs/g tissue, of 41.5, 63.7 and 58.6% was observed in the liver, intestine and liver/intestinal tissue combined. Furthermore, S. mansoni-specific IgG level significantly increased with hesperidin treatment, whereas IgA and IgE levels were not significantly changed. IgM levels decreased in response to cercarial antigen preparation but were not altered in response to soluble worm or soluble egg antigen. As in hesperidin-treated mice, praziquantel-treated mice showed a similar pattern of specific antibody response to S. mansoni antigens. The present study represents the first report on the effects of the schistosomicidal activity of hesperidin. Introduction Schistosomiasis, caused by trematode flatworms of the genus Schistosoma, is one of the most significant, neglected tropical diseases in the world. An estimated 779 million people are at risk for schistosomiasis, with 207 million infected in 76 countries and territories (Lammie et al., 2006; Steinmann et al., 2006). Approximately 120 million people are symptomatic and 20 millions suffer from severe and debilitating disease (Chitsulo et al., 2000; Engels et al., 2002; Finkelstein et al., 2008). The most common anti-schistosomiasis drug used in endemic areas is praziquantel, which is effective against adult worms (World Health Organization, 1993). However, praziquan- tel does not prevent re-infection, is inactive against juvenile schistosomes and only possesses a limited effect on the already developed liver and spleen lesions (Chatterjee et al., 2002; Silva et al., 2003). A treatment strategy that relies on a single drug is not satisfactory due to the high probability of emergence of drug-resistant *Fax: þ 966 2 7250528; E-mail: gm_allam@yahoo.com Current address: Department of Microbiology, College of Medicine, Taif University, Taif, Saudi Arabia. Journal of Helminthology (2014) 88, 362–370 doi:10.1017/S0022149X13000278 q Cambridge University Press 2013