Consumption of Hibiscus sabdariffa L. aqueous extract and its impact on systemic antioxidant potential in healthy subjects

J Sci Food Agric. 2012 Aug 15;92(10):2207-18. doi: 10.1002/jsfa.5615. Epub 2012 Feb 13.


Background: To evaluate health benefits attributed to Hibiscus sabdariffa L. a randomized, open-label, two-way crossover study was undertaken to compare the impact of an aqueous H. sabdariffa L. extract (HSE) on the systemic antioxidant potential (AOP; assayed by ferric reducing antioxidant power (FRAP)) with a reference treatment (water) in eight healthy volunteers. The biokinetic variables were the areas under the curve (AUC) of plasma FRAP, ascorbic acid and urate that are above the pre-dose concentration, and the amounts excreted into urine within 24 h (Ae(0-24) ) of antioxidants as assayed by FRAP, ascorbic acid, uric acid, malondialdehyde (biomarker for oxidative stress), and hippuric acid (metabolite and potential biomarker for total polyphenol intake).

Results: HSE caused significantly higher plasma AUC of FRAP, an increase in Ae(0-24) of FRAP, ascorbic acid and hippuric acid, whereas malondialdehyde excretion was reduced. Furthermore, the main hibiscus anthocyanins as well as one glucuronide conjugate could be quantified in the volunteers' urine (0.02% of the administered dose).

Conclusion: The aqueous HSE investigated in this study enhanced the systemic AOP and reduced the oxidative stress in humans. Furthermore, the increased urinary hippuric acid excretion after HSE consumption indicates a high biotransformation of the ingested HSE polyphenols, most likely caused by the colonic microbiota.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anthocyanins / pharmacology*
  • Anthocyanins / urine
  • Antioxidants / metabolism
  • Antioxidants / pharmacology*
  • Area Under Curve
  • Ascorbic Acid / blood
  • Biomarkers / metabolism
  • Biotransformation
  • Female
  • Glucuronides / pharmacology*
  • Glucuronides / urine
  • Health
  • Hibiscus / chemistry*
  • Hippurates / urine
  • Humans
  • Male
  • Malondialdehyde / urine
  • Oxidative Stress / drug effects*
  • Plant Extracts / pharmacology*
  • Polyphenols / pharmacology*
  • Polyphenols / urine
  • Reference Values
  • Uric Acid / blood
  • Young Adult


  • Anthocyanins
  • Antioxidants
  • Biomarkers
  • Glucuronides
  • Hippurates
  • Plant Extracts
  • Polyphenols
  • Uric Acid
  • Malondialdehyde
  • Ascorbic Acid
  • hippuric acid