Subchronic toxicity (90 days) of StemEnhance™ in Wistar rats

Levent Dirikolu¹, Thushara Chakkath¹, Susan Ball-Kell², Christy Elamma², David J Schaeffer^1
1Department of Comparative Biosciences, ²Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA

Abstract: This study evaluated the subchronic toxicity of StemEnhance™, an extract of the blue-green alga Aphanizomenon flos-aquae that is used as a health supplement. Groups of 12 rats of each sex were given either 5% glycerin in water (control) or 200 mg/kg of StemEnhance prepared in 5% glycerin in water for 90 days by oral gavage. The administration of StemEnhance had no effect on behavior, food and water intake, growth, or survival. Values at the end of dosing and observation periods did not reveal differences between treated and control groups for hematology and clinical chemistry. There were no significant differences in the gross and histopathology of the reproductive organs in either males or females. Sperm motility parameters were similar for control and treated males. Our results show that StemEnhance at doses ~7 times the maximum label-recommended daily dose did not produce adverse effects in Wistar rats after subchronic treatment.

Keywords: algal toxicology, blue-green algae, cyanobacteria, Aphanizomenon flos-aquae