Giardisis is a debilitating disease caused by gastrointestinal parasites of the genus Giardia. High-antioxidant T. ferdinandiana fruit extracts were investigated for the ability to block Giardia duodenalis growth. Methanolic and aqueous extracts had the most potent growth inhibitory activity (IC50 values of approximately 700 and 140 μg/ml, respectively). Ethyl acetate and chloroform extracts also inhibited G. duodenalis growth, albeit with lower potency. The hexane extract was completely devoid of G. duodenalis growth inhibitory activity. All extracts were nontoxic in the Artemia fransiscana bioassay. Nontargeted HPLC-quadrupole time-of-flight (QTOF) mass spectroscopy (with screening against three compound databases) putatively identified 17 compounds in all of the inhibitory extracts but not in the inactive hexane extract. The low toxicity of the Terminalia ferdinandiana fruit extracts and their potent G. duodenalis growth inhibitory bioactivity indicate their potential as medicinal agents in the treatment and prevention of this disease.

Giardia duodenalis is a protozoal, intestinal parasite that is a common aetiological agent of infectious diarrhoea in humans worldwide. Chemotherapeutic intervention presently offers a limited range of drugs and these are usually only employed after clinical diagnosis. Moreover, these drugs are ineffective against the infectious cysts, can produce unpleasant side effects, and are expensive with limited availability in developing countries. Frequent reports of drug toxicity, treatment failure and parasite drug resistance have, in some instances, also resulted in the increasing reluctance to over-prescribe synthetic anti-microbials. Alternatively, there is now mounting evidence to suggest that some of the naturally derived, medium-chain, saturated fatty acids (MCSFAs) possess anti-microbial and anti-parasitic properties. We have therefore examined the effects of four different fatty acids on G. duodenalis trophozoites in vitro. Cytotoxicity was determined using fluorescence, scanning and transmission electron microscopic techniques and standard cytotoxicity assays. Our studies have confirmed that the MCSFA, dodecanoic acid (C: 12) (common name: lauric acid), is anti-giardial, with an LD50 concentration comparable to that of metronidazole, the drug of choice in the treatment of giardiasis. Dodecanoic acid appeared to induce trophozoite death by accumulating within the parasite cytoplasm resulting in rupture of the cell membrane. This study has opened fresh avenues for development of natural drug therapy in which food supplementation may augment, or even replace, some of the standard chemotherapeutic agents presently employed in the treatment of giardiasis and possibly other infectious intestinal diseases.

Background: Giardiasis is a debilitating disease caused by gastrointestinal parasites of the genus Giardia. Tasmannia lanceolata (Tasmanian pepper berry) has a high anti-oxidant capacity and has documented therapeutic properties for a variety of pathogenic diseases. Materials and methods: Solvent extracts of T. lanceolata berry and leaf were investigated for the ability to block G. duodenalis growth. The IC 50 values of the extracts which displayed inhibitory activity were determined to quantify and compare their efficacies. Toxicity was determined using the Artemia franciscana nauplii bioassay. Active extracts were analysed by non-targeted HPLC-QTOF mass spectroscopy (with screening against 3 compound databases) for the identification and characterisation of individual components in crude plant extracts. Results: Methanolic, aqueous and ethyl acetate T. lanceolata berry and leaf extracts displayed potent G. duodenalis growth inhibitory activity. The methanolic extracts were the most potent growth inhibitors with IC 50 values of approximately 180 µg/ml and 420 µg/ml for the berry and leaf methanolic extracts respectively. The aqueous, ethyl acetate, chloroform and hexane extracts also inhibited G. duodenalis growth, albeit with lower potency. HPLC-QTOF mass spectroscopy analysis of the extracts

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One of the greatest challenges for healthcare professionals is the prevention and treatment of protozoal and helminthic parasitic infections. From our study we conclude that the prevalence of different pathogenic species of amoeba such as Entamoeba histolytica (4.2 vs. 0%) and G. lamblia (17.9 vs. 14%), (P value was equal to 1) was significantly higher among rural children compared to children from urban areas. In contrast, the prevalence of nematodes such as A. lumbricoides (21% vs. 1.1%), T. trichiura (8% vs. 0%) and A. duodenale (1%) was also significantly higher among rural children.