Joshua D. Lambert, Ph.D.

Research Interests:

The research focus of my laboratory is on the potential obesity and fatty liver disease preventive effects, as well as, the bioavailability and potential hepatotoxicity of dietary phytochemicals. Our primary focus currently is on the tea catechin, (-)-epigallocatechin-3-gallate (EGCG).

The emerging epidemic of obesity, and related complications including fatty liver disease, makes the development of preventive strategies a key public health concern. My laboratory is currently studying the effectiveness of EGCG, and other dietary phytochemicals, as obesity preventive agents with the goal of understanding the underlying mechanisms of action and maximizing preventive activity using mouse models.

Although dietary phytochemicals, including EGCG, have a long history of safe use as part of the diet, there is emerging evidence that high doses of some of these compounds, given in concentrated dose forms (capsules, tablets, etc.) may cause liver toxicity in humans. Research in my laboratory is focused on understanding the dose-response relationships and mechanisms of action underlying these potential toxicities in mice. We are studying the role of biotransformation and bioavailability in determining toxic potential of important dietary phytochemicals, and assessing the potential for phytochemical-drug interactions that could lead to adverse effects.

My laboratory is also interested in the potential lung cancer preventive activities of dietary phytochemicals either as single agents or in combination with pharmaceutical compounds. The focus is on establishing efficacy in cell culture and mouse models of lung cancer and studying the underlying mechanisms of action.

Selected Publications:

Bose M, Lambert JD, Ju J, Reuhl KR, Shapses SA, Yang CS. (2008) The major green tea polyphenol, (-)-epigallocatechin-3-gallate, inhibits obesity, metabolic syndrome, and fatty liver disease in high-fat fed mice. J Nutr. In press.

Lambert JD, Sang S, Yang CS. (2008) N-Acetylcysteine enhances the lung cancer inhibitory effect of epigallocatechin-3-gallate and forms a new adduct. Free Rad Biol Med. 44: 1069 - 74.

Lambert JD, Sang S, Yang CS. (2007) Possible controversy over dietary polyphenols: benefits vs risks. Chem. Res. Toxicol. 20: 583 - 5.

Hao X, Bose M, Lambert JD, Ju J, Lu G, Lee MJ, Park S, Husain A, Wang S, Sun Y, Yang CS. (2007) Inhibition of tumorigenesis in ApcMin/+ mice by green tea polyphenols (Polyphenon E) and individual catechins. Nutr. Cancer. 59: 62 - 9.

Lambert JD, Sang S, Yang CS. (2007) Biotransformation of green tea polyphenols and the biological activities of those metabolites. Mol. Pharmaceutics. 6: 819 - 825.

Bose M, Hao X, Ju J, Husain A, Park S, Lambert JD, Yang CS. (2007) Inhibition of tumorigenesis in ApcMin/+ mice by a combination of (-)-epigallocatechin-3-gallate and fish oil. J. Ag. Food Chem. 55: 7695 - 7700.

Lambert JD, Kwon SJ, Hong, J, Yang CS. (2007) Salivary hydrogen peroxide produced by holding or chewing green tea in the oral cavity. Free Radical Res. 41: 850 - 53.

Lambert JD, Sang S, Lu AYH, and Yang CS. (2007) Metabolism of dietary polyphenols and possible interactions with drugs. Current Drug Metabol. 8: 499 - 507.