Abstracts

Safety & Toxicity

Safety & Toxicity

Studied the acute effects of "Guarana", when compared to caffeine and placebo, (double blind study) on cognition, anxiety and sleep in 30 normal volunteers. Although results were negative it cannot be concluded that "Guarana" is harmless. Other studies shall be undertaken, administering "Guarana" on a long term basis, as popularly proclaimed.

Acute effects of the Paulinia cupana, "Guarana" on the cognition of normal volunteers. Galduroz-JC; Carlini-E-de-A. Rev-Paul-Med. 1994 Jul-Sep; 112(3): 607-11.

Mutagenic Effects

Genotoxic and mutagenic effects

Aqueous extracts of guarana, a species that belongs to the Sapindacae family, were analyzed for the presence of genotoxic activities in bacterial cells. The extracts of guarana were genotoxic as assessed by lysogenic induction in Escherichia coli and they were also able to induce mutagenesis in Salmonella typhimurium. Addition of S9 microsomal fraction, catalase, superoxide dismutase or thiourea counteracted the genotoxic activity of guarana, suggesting that oxygen reactive species play an essential role in the genotoxicity of aqueous guarana extracts. The genotoxic activity in the extracts was related to the presence of a molecular complex formed by caffeine and a flavonoid (catechin or epicatechin) in the presence of potassium.

Genotoxic and mutagenic effects of guarana (Paullinia cupana) in prokaryotic organisms. da Fonseca, C.A. et al. Mutat. Res. 1994,321(3):165-73.

Hyperglycemia

Hyperglycemia

According to this study, guarana (GW) may improve glycemic control by increasing blood glucose levels and glycogen utilization between meals. The effect of water Guarana extract, was measured in normal, exercised, and epinephrine-induced glycogenolytic mice. The guarana extract raised the blood glucose level and lowered the liver glycogen contents an hour after mice ingested maltose. GW also prevented exercise-induced hypoglycemia, but did affect blood glucose levels in epinephrine-induced glycogenolytic mice.

Miura T, Tatara M, Nakamura K, Suzuki I: Effect of guarana on exercise in normal and epinephrine-induced glycogenolytic mice, Biol Pharm Bull 1998 Jun; 21(6): 646-8

Toxicity/Antioxidant Activity

Toxicity/Antioxidant activity

According to this study, high doses of guarana do not cause toxicological symptoms. Its toxicity was examined in rats and mice subjected to acute and chronic administrations. The study found that guarana was very effective at low concentrations since it inhibited the process of lipid peroxidation. High doses of guarana did not reduce motor activity or alter the histopathological characteristics of bodily organs. In low doses, guarana may be an effective antioxidant against lipid peroxidation.

Mattei R, Dias RF, Espinola EB, Carlini EA, Barros SB: Guarana (Paullinia cupana): toxic behavioral effects in laboratory animals and antioxidants activity in vitro, J Ethnopharmacol 1998 Mar; 60(2): 111-6

Toxicity & Guarana

Toxicity

According to in vitro analysis, the concentration of guarana may affect cytotoxic activity.
Guarana was administered to Chinese hamster ovary (CHO) cells and bacterial cells (Photobacterium phosphoreum). The outcome indicated that the lowest concentration of guarana was nontoxic. However, the study notes that high doses of guarana may be harmful to human health.

Santa Maria A, Lopez A, Diaz MM, Munoz-Mingarro D, Pozuelo JM: Evaluation of the toxicity of guarana with in vitro bioassays, Ecotoxicol Environ Saf 1998 Mar; 39(3): 164-7