The objective of this project is to study the biological activities of ginger extract and its key constituents, [6]-gingerol and [6]-shogaol, and develop a ginger extract with high level of shogaols (GEHS) as a lung cancer preventive agent. Ginger, the rhizome of the plant Zingiber officinale, has been used as a herbal medicine in China, India, and Arabic countries since ancient times. Recently, ginger has received extensive attention due to its anti-oxidant, anti-inflammatory, and anti-tumor activities. The main principles in ginger are the series of pungent oleoresin constituents known as gingerols, with [6]-gingerol being the major component. Ginger also contains shogaol homologues that are formed by dehydration of corresponding gingerols during storage or thermal processing. In fresh ginger, very little shogaols can be detected. Whereas in dried ginger, the levels of shogaols can be even higher than gingerols in some preparations. Most researchers have considered gingerols as the active principles and have paid little attention to shogaols. Our recent results showed that [6]- shogaol has greater growth inhibitory activity (about 10 fold) on lung and colon cancer cell lines than [6]- gingerol. Our hypothesis is that shogaols can be the major active constituents of ginger preparations and GEHS has stronger cancer preventive effect than other ginger extracts.
The specific aims are: 1. To develop a GEHS preparation, study the bioavailability and biotransformation of [6]-shogaol and [6]-gingerol after administration of GEHS to mice, and find the optimal doses of GEHS for studies in mice. 2. To determine the inhibitory activities of GEHS and extract from fresh ginger (EFG) as well as [6]- shogaol and [6]-gingerol in a 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung carcinogenesis model in A/J mice. We believe that results from this project will provide the basic information on key active cancer preventive constituents in ginger extracts. The development of a standardized and a more active ginger extract preparation will facilitate future pre-clinical and clinical studies on the health benefit of ginger extracts.
Ginger has been cultivated for thousands of years as a spice and for medicinal purposes. Recent studies have shown that ginger has antioxidant, anti-inflammatory, and anti-tumor activities. However, it is unclear what the major active anti-tumor components in ginger are. The main principles in fresh ginger are the series of pungent oleoresin constituents known as gingerols, with [6]-gingerol being the major component. Whereas in dried ginger, shogaols, the dehydration products of gingerols during thermal processing, are predominant components. Their levels can be even higher than gingerols in some preparations. Most researchers have considered gingerols as the active principles and have paid little attention to shogaols. Our recent results showed that [6]-shogaol has greater growth inhibitory activity on lung and colon cancer cell lines than [6]-gingerol. In this project, we will develop and standardize ginger extract with high levels of shogaols (GEHS), and study the bioavailability and biotransformation of [6]-shogaol and [6]-gingerol in GEHS in comparison to that of the compound administered alone in mice. Furthermore, we will determine the inhibitory activities of GEHS and extract from fresh ginger, as well as [6]-shogaol and [6]-gingerol in a NNK-induced lung carcinogenesis model in A/J mice. NNK (4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone) is a tobacco carcinogen, and this model is highly relevant to human lung cancer formation. Results from these studies will make it possible to 1) develop an optimal preparation process of ginger extract that will be effective in the prevention of lung cancer;2) provide a scientific basis for standardization of ginger supplements aim to make chemoprevention health claims;3) determine the plasma and tissue levels of shogaols and gingerols which provide basis for understanding the chemopreventive effects;and 4) improve the quality of future clinical trials on chemopreventive effect through use of standardized extracts and the development of exposure biomarkers for the consumption of ginger products.
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