Evaluation of in vivo sub-chronic and heavy metal toxicity of under-exploited seaweeds for food application

Abstract

Seaweeds are known to be rich source of micronutrients and bioactive compounds. The main objective of this study was to find the toxicological evaluation and heavy metal accumulation of five under-exploited edible seaweeds in animal model followed by dosage determination for regular consumption as a food by humans and food application. Some under-exploited seaweeds like Acanthophora spicifera, Gracilaria edulis, Padina gymnospora, Ulva fasciata and Enteromorphoa flexuosa were selected forthis study. The ED50 study was conducted in Wistar strain rats for 90 days with single dose administration of seaweed extract of 2000 mg/kg/BW. At the end of 90th day rats were euthanized, serum of the rats examined for biochemical, haematological, liver enzymes, and vital organs were dissected out for heavy metal analysis and urine samples collected intermediary to analyse electrolyte minerals. Result showed that no-observed adverse effect level (NOEL) on five seaweeds, did not cause any death and no significant variation in biochemical and haematological parameters, the values were found within standard values. Locomotor activity suggests normal action, organ necropsy showed no histopathology lesions, regular cell alignment in the tissue cross section. Heavy metals like arsenic, lead were found in trace amount and no mercury accumulation found in kidney, liver and brain of rats. Therefore, these five seaweeds were safe for human consumption and also for food product developement. Keywords: Seaweed, Sub-chronic toxicity, Acanthophora spicifera, Gracilaria edulis, Padina gymnospora, Ulva fasciata, Enteromorphoa flexuosa