The effects of saturated fatty acids on Giardia duodenalis trophozoites in vitro

Abstract

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.

In Vitro Effects of Thiazolides on Giardia lamblia WB Clone C6 Cultured Axenically and in Coculture with Caco2 Cells

“…Parasites exhibited a tendency to swell, as described earlier (26), and in contrast to NTZ-treated parasites, trophozoites did not exhibit these alterations on the ventral disk membrane, but significant lesions were visible on the dorsal surface, most notably at 24 h of MTZ treatment. Similar alterations have been described previously on trophozoites treated with saturated fatty acids (23). Studies on the ultrastructural effects of these drugs towards cysts have revealed that NTZ and MTZ exhibit different effects, and they also differentially affect cyst viability (3).…”

Safety and efficacy of sodium caprate in promoting oral drug absorption: from in vitro to the clinic

“…In addition to antimicrobial activity, C 10 has been shown to reduce adhesion of S. typhimurium to isolated ileal mucosa of rats [207]. Capric acid has antiviral activity against a number of enveloped viruses [209], antifungal activity [211] as well as anti-protozoal activity against the common intestinal parasite, Giardia duodenalis [212]. In cultured monolayers of human airway epithelial cells, pre-treatment with C 10 increased the translocation of adenovirus (AdlacZ and Ad-CFTR) vectors [148].…”

An examination of the antibacterial, antifungal, anti-Giardial and anticancer properties of Kigelia africana fruit extracts

“…[54] Recent studies have highlighted the potential of plant medicines and have demonstrated that some plant components are very effective inhibitors of Giardia duodenalis growth with similar potency to the gold standard drug metranidazole. [53] Our studies demonstrates that K. africana fruit also possesses anti-Giardial activity. Whilst, further studies are required to identify the active component(s), previous studies have identified vermonoside as being inhibitory against amoebic protozoans.…”

“…Giardial infection (giardiasis) is a re-emerging disease which afflicts large numbers of individuals worldwide, with higher incidence in countries with poorer socio-economic conditions, inadequate sanitary conditions, untreated water supplies and poor diet. [53] Whilst generally not fatal, giardiasis results in debilitating symptoms including bloating, diarrhoea, excess gas, loss of appetite, loose and watery stool, stomach cramps and haematuria. Currently, there are only a narrow range of drugs effective against giardiasis, including quinalones and imidazole derivatives.…”

“…None of these drugs is ideal as they produce unpleasant side effects including nausea, vertigo, vomiting, diarrhoea and hallucinations. [53,54] Furthermore, increasing reports of the failure of current treatments to address this disease indicates a developing drug resistance of several Giardia species. [54] Recent studies have highlighted the potential of plant medicines and have demonstrated that some plant components are very effective inhibitors of Giardia duodenalis growth with similar potency to the gold standard drug metranidazole.…”