Roselle extract was not mutagenic for Salmonella
typhimurium strain TA100 with or without S9 mix
up to 25.0 mg/plate. However, in strain TA98, the
extract induced 86 and 107 His+ per 25.0 mg in the
presence and absence of the metabolic activation
system. Antibacterial activity was observed at
50 mg/plate in both strains with and without S9
mix (Table 1).