The inhibitory extracts also contained a relative abundance of the gallotannin components gallic acid (Fig. 4b) and chebulic acid (Fig. 4q). Gallotannins have been reported to inhibit the growth of a broad spectrum of microbial species through a variety of mechanisms including binding cell surface molecules including lipotoichoic acid and proline-rich cell surface proteins and by inhibiting glucosyltransferase enzymes. Whilst we were unable to find similar studies reporting inhibitory effects of tannins on Giardia spp. growth, a number of studies have reported high tannin contents in a variety of plants used in traditional medicine to treat giardiasis. Furthermore,tannins extracted from other plant species inhibit the growth of other protozoa including Schistosoma mansoni.