Novel anti-amoebic properties of agarophytes Gracilaria changii and Gracilaria salicornia extracts

Acanthamoeba is a ubiquitous and parasitic protozoan capable of causing serious human infections, resulting in blindness and even death. Seaweeds are abundant and widely known for their antimicrobial properties. This study aims to unveil the anti-amoebic potential of two Malaysian red seaweeds, Gracilaria changii and Gracilaria salicornia on Acanthamoeba castellanii. Water, methanol and ethyl acetate extracts of G. changii and G. salicornia were tested against A. castellanii. Liquid chromatography-mass spectrometry (LC-MS) analysis was carried out to identify the compounds responsible for the anti-amoebic effect. Methanol extract of G. salicornia showed a significant growth inhibition of 22 % in A. castellanii trophozoites. Cytotoxicity of these extracts were shown to be minimal in human keratinocyte cells through cell viability assay. Data from LC-MS revealed fourteen compounds with reported biological activities. These findings suggest the use of G. changii and G. salicornia as potential sources of anti-amoebic compounds.