Determination of the concentration of major active anti-emetic constituents within commercial ginger food products and dietary supplements

Introduction : Studies suggest that the bioactive compounds contained within the rhizome of ginger (Zingiber officinale) could exert a beneficial effect on the symptoms of several chronic conditions (e.g. diabetes, arthritis) and in the reduction of nausea. However, it is unknown if ginger supplements and food products contain sufficient quantities of the necessary active ingredients to achieve a therapeutic effect. This study analyzed twenty commercially available ginger products including ginger dietary supplements, ginger spices (ground dried ginger), and ginger-containing drinks and food products and determined the concentration of [6]-, [8] - and [10]- gingerol and [6] - and [10]-shogaol.
Methods : The samples were extracted prior to separation by Reversed Phase-High Performance Liquid Chromatography (RP-HPLC) and detected by ultraviolet (UV) spectrophotometry.
Results : Considerable variation between individual items within each food type was observed. Per gram, ginger supplements, particularly the standardized extracts, contained the greatest concentration of measured compounds (10.08 ± 7.92 mg, mean ± standard deviation), while the concentration of compounds within spices (9.29 ± 6.73 mg), beverages (1.77 ± 1.06 mg), confectionery (0.43 ± 0.32 mg), and teas (0.13 ± 0.00 mg) was considerably lower. When the concentration of compounds was measured per standardized serve, four ginger confectionery and beverage products contained total gingerol and shogaol concentrations that were similar to the analyzed dietary supplement.
Conclusion : Of the twenty commercially available ginger products examined, those with the highest content of active, antiemetic constituents were the standardized ginger extracts and supplements although ginger spices also showed high levels of active constituents per serve. In addition, standard deviation reveals a large variation within each product type.