Identification of the Chemical Constituents in Ginger (Zingiber officinale) Responsible for Thermogenesis

Abstract

To compare the thermogenic properties of crude drugs derived from ginger, the activities to peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) of methanol extracts of “Shokyo” (dried rhizome of Z. officinale var. rubens), “Kankyo” (steamed and dried rhizome of Z. officinale var. rubens), “Red ginger” (Indonesian dried rhizome of Z. officinale var. rubrum) and “White ginger” (Indonesian dried rhizome of Z. officinale var. amarum), were examined. The extracts of the four specimens were analyzed by liquid chromatography mass spectrometry (LC-MS). The results showed that “Shokyo” and “White ginger” strongly stimulated PGC-1α and that the amount of [10]-shogaol (6) in these was higher than in “Kankyo” and “Red ginger”. Gingerol-related compounds were isolated or prepared in order to identify the compounds responsible for stimulating PGC-1α. As a result, [10]-gingerol (3), [10]-shogaol (6), [10]-gingerdiols (11, 12) and [10]-gingerdiols 3,5-diacetate (17, 18) were identified as the active constituents, while the main constituents, [6]-gingerol (1) and [6]-shogaol (4), did not show any significant PGC-1α activity. These results suggest that gingerol-related compounds with long alkyl side chains contribute to the thermogenic properties of ginger.