Dual impact of Pulicaria undulata extracts on colonic motility and Blastocystis structure: two factors linked to inflammatory bowel syndrome

Abstract Background Irritable bowel syndrome (IBS) is considered one of the most common diseases that affect the gastrointestinal tract. Several studies have shown that microbiota change and microorganisms like Blastocystis significantly contribute to IBS pathogenesis. Blastocystis resistance to commonly used antiparasitic drugs has emerged as an important subject for ongoing research. Introducing a new antiparasitic agent presents significant potential for improved management. Pulicaria undulata (P. undulata ) extracts showed potential antiparasitic activity in previous research. Other reports clarified a possible gastrointestinal protective effect. However, no available studies have explored its potential activity against Blastocystis species (spp.) and its effect on colonic contractility. Objectives This study was designed to investigate the impact of flower and leaf methanolic extracts of P. undulata on colon motility, which is directly related to IBS, and to assess their in vitro efficacy against Blastocystis subtypes isolated from symptomatic patients. Materials and methods P. undulata was extracted and metabolites were analyzed. Isolated subtypes of Blastocystis spp. from collected samples were identified. Extracts effect on colonic motility and contractility was assessed in vitro using isolated colonic segments. In addition, cultured Blastocystis spp. was challenged with different concentrations of flower and leaf extracts as well as nitazoxanide. Structural, morphological, and ultrastructural alterations were evaluated using light and scanning electron microscopes. Results The amplitude of colonic contractility decreased in response to P. undulata methanolic extracts, reflecting its possible spasmolytic effect on colonic motility, which was more noticeable with leaf than flower methanolic extracts. In vitro effect on ultrastructure of Blastocystis was seen with an obvious impact of both extracts on the shape and size of the parasite, which was mostly time and dose dependent. As for the molecular study, the most commonly isolated Blastocystis subtype was subtype 1. GC–MS analysis of silylated P. undulata flower and leaf methanolic extracts identified 46 metabolites. Flowers’ methanolic extract exhibited greatly higher flavonoid concentration than leaves. Conclusion The findings of this study emphasize probable therapeutic effects of P. undulata plant methanolic extracts in improving IBS symptoms by decreasing colonic motility while opening avenues for future research to consider P. undulata as a safe natural treatment of the implicated co-infection of Blastocystis .