Analysis of food supplements containing garlic (Allium sativum L.) dry extract using high-performance liquid chromatography (HPLC) method

Aim: to qualitatively and quantitatively evaluate food supplements containing garlic (Allium sativum L.) dry extract sold in Lithuanian and Polish pharmacies using high HPLC method. Objectives: to identify organic sulfur compounds in the contents of food supplements using HPLC. To evaluate quantity of identified compounds using HPLC and compare determined quantities of identified compounds in different food supplements. To compare determined quantities of organic sulfur compounds with quantities declared by manufacturer on the labels. Object and method: 7 food supplements containing garlic dry extract sold in Lithuanian and Polish pharmacies from different European manufacturers. The samples were prepared in two ways: by inhibiting and activating enzyme alliinase. Qualitative and quantitative analysis of organic sulfur compounds was performed using HPLC method. As eluent A was used the mixture of sodium dihydrogen phosphate dehydrate, 1-heptanesulfonic acid sodium salt monohydrate and as eluent B - the mixture of acetonitrile, sodium dihydrogen phosphate dehydrate and 1-heptanesulfonic acid sodium salt monohydrate. The column was thermostated at 38 ºC, the flow rate of 0,4 ml/min was used. Detection was performed at 208 nm wavelength UV-light. Results and conclusions: After inhibiting the enzyme alliinase, (-)-L-Alliin, SAC, GLUAlCs, GLUPeCs, GLUPheAla were identified. After activating alliinase, allicin (diallyl thiosulfinate) was identified as well. The results show that only 2 supplements out of 7 comply with the requirements of chromatographic profiles. Determined amounts of allicin and alliin do not comply with the data provided on a label of food supplement-3 and 6. Determined amount of GLUAlCs complies with 95,24% (by inhibiting alliinase) and 97% (by activating alliinase) amount provided on the label of food supplement-3