Anthraquinone in Indonesian infusion tea: analysis by HPLC–UV and risk assessment

Abstract

Background: Detection of anthraquinone in tea samples marketed in Europe is raising a concern due to the possible carcinogenicity of this compound. The European Union has set a very low maximum residue level (MRL) for anthraquinone residue in tea (0.02 mg/kg). The available method analyses for anthraquinone are mostly by gas chromatography (GC) coupled by mass spectrophotometer (MS) which are relatively more expensive instruments and not always available to moderately equipped laboratories. This study was aimed to analyze anthraquinone in infusion tea of Indonesian commercial tea using liquid chromatography–ultraviolet detector (HPLC–UV) and then assessed the risk associated with consuming infusion tea with anthraquinone residue. The analysis was conducted by low-volume liquid–liquid extraction followed by quantification by HPLC–UV, while the risk assessment was analyzed by calculating the risk quotient (HQ) and carcinogenic risk (R) based on the highest anthraquinone level detected in the sample. Results: The low-volume liquid–liquid extraction followed by HPLC quantification was able to analyze anthraquinone in infusion tea with linearity of 0.9990 at 8.33 to 83.33 μg/L; precision of 2.25%; and recovery of 96.19 to 102.98%. The anthraquinone levels in infusion tea of Indonesian commercial tea varied from not detected to 0.44 μg/L. The calculated HQ is lower than 1 (0.033), implying that consuming Indonesian infusion tea with the detected anthraquinone residue is unlikely to cause non-carcinogenic effect. The R is 2.63 × 10−6, but no parametric values have been regulated for anthraquinone; thus, its carcinogenic effect cannot be further assessed. Conclusion: Low-volume liquid–liquid extraction followed by quantification by HPLC–UV was able to analyze anthraquinone in infusion tea of Indonesian commercial tea samples. Risk assessment showed no prove of adverse effect related to consuming infusion tea as high as the highest concentration detected in infusion tea samples. However, risk associated at higher concentration and/or long-term consumption may not be neglected.[Figure not available: see fulltext.].