Activity of Iranian Medicinal Herbs against Human Intestinal Parasites (HIP): A Systematic Review

Background and objectives: Intestinal parasitic infections are a major public health problem worldwide, especially in developing countries. It is estimated that around 3.5 billion people are infected with intestinal parasites. Human intestinal parasites (HIP) are clinically important due to broad epidemiological distribution, reinfection and drug resistance. In the last decades, bioactive compounds from herbs were used against a wide variety of microorganisms including parasites. We aimed to perform a systematic review on studies on the effects of medicinal herbs on HIPs in Iran. Methods: Relevant scientific publications until April, 2015 were extracted from five English databases (PubMed, Google Scholar, Ebsco, Science Direct and Scopus) and four Persian databases (Magiran, Irandoc, IranMedex and the Scientific Information Database). Results: A total of 18 papers and two dissertations met the inclusion criteria. Overall, 22 different plant extracts were used against Giardia lamblia, Entamoeba histolytica, Cryptosporidium and Hymenolepis nana. Based on the results, the extracts could exert time- and dose-dependent inhibitory effects against the tested HIPs. Five plants types including Allium, Chenopodium botrys, Carum copticum, F. asafoetida and Artemisia annua were able to completely inhibit the tested parasites, while Thymus vulgaris and A. paradoxum showed the lowest inhibitory effect (7%). Conclusions: Given the findings, it is recommended to conduct in vivo studies on medicinal herbs with favorable in vitro effects against HIPs.