Evaluation of the toxicity of guarana with in vitro bioassays

Ecotoxicol Environ Saf. 1998 Mar;39(3):164-7. doi: 10.1006/eesa.1997.1576.


A natural stimulant, Paullinia cupana, commonly called guarana, was tested for its ability to induce in vitro toxicity in Chinese hamster ovary (CHO) cells and bacterial cells (Photobacterium phosphoreum). The cytotoxic effects of aqueous guarana extracts were evaluated by three endpoint systems: neutral red (NR) uptake assay, total protein content [kenacid blue (KB)] assay, and tetrazolium (MTT) assay. The Microtox test was also used. Results indicated that the lowest concentration of guarana tested was not toxic and that the IC50 values calculated with the NR, KB, and MTT assays were lower than the highest concentration tested (40 mg/ml). There was no significant difference in cytotoxicity between the three test systems. The EC50 values obtained with the Microtox assay were consistent with these data. The present in vitro analysis suggests that the concentration of guarana is of critical importance in its cytotoxic activity and high doses could be harmful to human health.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells / drug effects
  • Caffeine / toxicity*
  • Cell Division / drug effects
  • Cricetinae
  • Drug Combinations
  • Indicators and Reagents
  • Neutral Red
  • Organic Chemicals
  • Photobacterium / drug effects*
  • Plant Extracts / toxicity
  • Proteins / analysis*
  • Seeds
  • Tetrazolium Salts
  • Theobromine / toxicity*
  • Theophylline / toxicity*


  • Drug Combinations
  • Indicators and Reagents
  • Organic Chemicals
  • Plant Extracts
  • Proteins
  • Tetrazolium Salts
  • guarana powder
  • 4-anisyltetrazolium blue
  • kenacid blue
  • Neutral Red
  • Caffeine
  • Theophylline
  • Theobromine