The analysis of supplements containing turmeric (Curcuma longa L.) extract using high performance liquid chromatography (HPLC) method

The object and methods of the research: object of the research – food supplements containing turmeric (Curcuma longa L.) extract. The qualitative and quantitative analysis was performed by HPLC method. The mobile phase consisted of eluents: eluent A (0,05 % tri-fluoracetic acid in water) and eluent B (100 % acetonitrile). Column temperature was 25 ºC, the flow rate was 1 mL/min. Curcumin was analyzed using PDA detector at a wavelength of 420 nm. The aim of the research: to perform qualitative and quantitative analysis of curcuminoids found in supplements (bought in Lithuania and Poland) which contain turmeric (Curcuma longa L.) extract using HPLC method. The objectives of the research: to apply and validate the HPLC methodic for qualitative and quantitative analysis of bioactive substances found in turmeric extract; to determine the qualitative and quantitative composition of curcuminoids in chosen food supplements using HPLC method; to compare the composition of bioactive substances in food supplements containing turmeric extract and commonly used turmeric spice; to compare the quantity of curcumin determined during the analysis with the quantity specified on the label of the supplements. The results and conclusions of the research: during qualitative analysis two bioactive substances – curcumin and demethoxycurcumin – were identified. During quantitative analysis the quantity of those substances was determined. In two of the food supplements (MP_2, MP_4) the quantity of curcumin is higher than in the spice of turmeric (P). 11 449,700 ± 0,02 µg/g of curcumin were determined in P, 17 955,350 ± 0,01 µg/g in MP_2 and 160 423,500 ± 0,02 µg/g in MP_4. Two of the supplements had specified amount of curcumin written on the label, after analysis both of them matched that quantity. On the label of MP_3 2 mg of curcumin were written and 2,3 mg were determined during analysis, on the label of MP_4 – 175 mg, after analysis – 309 mg. The quantity of curcumin in MP_4 that we determined was almost two times higher than the one written on the label. This result might suggest that the producers of the supplement used the extract of curcumin instead of the extract of turmeric