Planta Med 2008; 74 - PC99
DOI: 10.1055/s-0028-1084617

Variations in gingerols and chromatographic fingerprints of ginger root extracts from different preparation methods may account for bioactivity discrepancies among investigations

Z Liu 1, D Liu 1, G Chou 1, 2, S Xu 1, A Zuberi 3, J Ye 3
  • 1Louisiana State University Agricultural Center, 227 Highland Road, Baton Rouge, LA 70703, U.S.A
  • 2Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Road, Shanghai 201203, P.R. China
  • 3Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808, U.S.A

The antidiabetic activity of Ginger root is not clear [1, 2]. The attempt to interpret this discrepancy is often hindered by the lack of chemical analyses of the studied agents. In this study, ginger root samples were prepared with methods differing in ginger type (fresh or dry), solvents (water, saline water, or aqueous alcohol), extraction methods (maceration, boiling, or under pressure), and ginger sources. The resulting samples were analyzed quantitatively for several characteristic gingerols (6-, 8-, and 10-gingerols, and 6-shogaol) and qualitatively for other unknown constituents. It was found that oven-drying of fresh ginger root did not significantly degrade gingerols. Aqueous ginger root extracts had significantly lower gingerols contents than aqueous ethanol extracts. Among the aqueous ginger extracts, fresh water extracted significantly more gingerols than salt (saline) water. Room temperature water, boiling water, and pressurized water methods resulted in ginger root extracts with 0.66mg/g, 2.96mg/g, and 0.01mg/g 6-gingerol, respectively. Chromatographic fingerprints showed that 50% aqueous ethanol provided a most balanced and diverse extract consisting of significant amounts of gingerols as well as non-gingerol constituents. Different sources of ginger were drastically different in gingerols levels. The variations of gingerols and other constituents associated with different preparation methods can contribute to bioactivity discrepancies among different investigations. Therefore, quantitative and qualitative analyses of ginger root extracts are needed in all investigations to allow cross study comparisons and reproduction of the observed bioactivity.

Acknowledgements: This work is funded through the Botanical Research Center award (P50AT002776–01) from the National Center for Complementary and Alternative Medicine and the Office of Dietary Supplements, the U.S. National Institutes of Health and the LSU AgCenter Technology Transfer Fund.

References: 1. Al-Amin et al. (2006), Br J Nutr. 96:660–6. 2. Islam and Choi (2008), J Med Food 11:152–159.