Risks and benefits associated with tribulus terrestris products assessed by phytochemical and pharmacological screening

Abstract

Recommendations of products with Tribulus terrestris as anabolic enhancers are based on empirical data. Exposure, especially of athletes, is very high, being among the most widely used nutritional supplements. Consumption of products containing Tribulus terrestris extracts has increased rapidly in the past few years due to the high content of sterol saponosides, compounds with presumed anabolic properties. Because of this upward surge, their efficacy and/or their safety are more and more often questioned. Commercialized dietary supplements, are often mislabelled, adulterated, or contaminated, therefore an evaluation of benefit/risk balance should always be conducted. Our study aimed to analyse an herbal drug and a food supplement frequently encountered on the market. Total polyphenolic and total saponosides content were determined. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine mineral element content of Tribulus terrestris products. Antioxidant and antimicrobial activities were assayed. The extract obtained with the herbal drug had no antibacterial effect. The extract from the capsules, however, was active against all tested strains with higher activity against Methicillin-resistant Staphylococcus aureus and Escherichia coli (MIC = 0.78 mg/mL). Trace elements were quantified, and dose-related risks were outlined, raising awareness regarding the aluminum and nickel content in the herbal drug.