title: Differential effectiveness of berry polyphenols as anti-giardial agents.
abstract: Following previous work on the anti-giardial effect of blueberry polyphenols, a range of polyphenol-rich extracts from berries and other fruits was screened for their ability to kill Giardia duodenalis, an intestinal parasite of humans. Polyphenol-rich extracts were prepared from berries using solid-phase extraction and applied to trophozoites of Giardia duodenalis grown in vitro. All berry extracts caused inhibition at 166 μg gallic acid equivalents (GAE)/ml phenol content but extracts from strawberry, arctic bramble, blackberry and cloudberry were as effective as the currently used drug, metronidazole, causing complete trophozoite mortality in vitro. Cloudberry extracts were found to be the most effective causing effectively complete trophozoite mortality at 66 μg GAE/ml. The polyphenol composition of the more effective berry extracts suggested that the presence of ellagitannins could be an important factor. However, the potency of cloudberry could be related to high ellagitannin content but also to the presence of substantial amounts of unconjugated p-coumaric acid and benzoic acid. These in vitro effects occur at concentrations easily achievable in the gut after berry ingestion and we discuss the likelihood that berry extracts could be effective anti-giardial agents in vivo.
authors.affiliation: Dietetics, Nutrition and Biological Sciences, Queen Margaret University, Clerwood Terrace, Edinburgh EH12 8TS, UK.
authors.forename: J-P
authors.initials: JP
authors.lastname: Anthony
authors.forename: L
authors.initials: L
authors.lastname: Fyfe
authors.forename: D
authors.initials: D
authors.lastname: Stewart
authors.forename: G J
authors.initials: GJ
authors.lastname: McDougall
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D019817:Benzoic Acid / Q000494:pharmacology; D029798:Blueberry Plants / Q000737:chemistry; D002452:Cell Count; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D003373:Coumaric Acids / Q000494:pharmacology; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D031985:Fragaria / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D016829:Giardia lamblia / Q000187:drug effects* / Q000254:growth & development; D005873:Giardiasis / Q000188:drug therapy* / Q000469:parasitology; D047348:Hydrolyzable Tannins / Q000494:pharmacology; D013058:Mass Spectrometry; D008795:Metronidazole / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011422:Propionates; D013045:Species Specificity; D053058:Trophozoites / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000890:Anti-Infective Agents; D003373:Coumaric Acids; D005419:Flavonoids; D047348:Hydrolyzable Tannins; D010936:Plant Extracts; D059808:Polyphenols; D011422:Propionates; D008795:Metronidazole; D019817:Benzoic Acid; C495469:p-coumaric acid