Scientists from the Agricultural Research Service of the US Department of Agriculture and US Davis report that the citrus extract may also decrease select liver enzymes that can be elevated in certain chronic diseases, such as metabolic syndrome, diabetes, and CVD.
The data is published in the Journal of Functional Foods and form the basis for a patent application by USDA, said Darshan Kelley, PhD, lead author on the new paper. The patent covers uses for limonin glucoside.
RCT data
Previous studies in both humans and animals have shown that mixtures of limonoid glucosides can exert various health benefits, but the new study investigated the potential metabolic effects of purified citrus limonin glucoside (the structure is shown to the right).
Ten overweight/obese men and women were recruited to participate in the cross-over study and given orange flavored drinks formulated with or without 500 mg/day of limonin glucoside for 56 days. This dose of limonin glucoside is equivalent to that obtained from six 8oz glasses of orange juice. After this period, the participants switched to the other drink for a further 56 days.
The study is the first pilot study to use purified limonin glucoside in humans in a placebo-controlled study where each subject served as his/her own control, said the researchers.
Results showed that limonin glucoside did not affect levels of blood lipids, lipoproteins or their particle sizes, glucose, or insulin. However, biomarkers of inflammation MMP-9 and TNF-alpha decreased significantly by 38.7% and 10.7%, respectively
In addition, levels of specific liver enzymes, including gamma-glutamyl transferase, alanine aminotransferase, and alkaline phosphatase decreased by 33.8%, 13.1%, and 10.1%, respectively. “Since liver enzymes are elevated in metabolic syndrome, NAFLD, diabetes, CVD, and chronic kidney disease and liver cancer, LG may be useful in the prevention and/or treatment of those diseases,” they wrote.
Dr Kelley and his co-workers noted that no specific adverse effects were observed, which supported the safety of the ingredient.
“This study demonstrates for the first time that supplementing the diets of overweight and obese human subjects with purified limonin glucoside significantly decreased circulating concentrations of liver proteins,” they wrote. “Because elevation in the activity of these proteins even within the so called normal ranges is associated with increased risk for a number of chronic inflammatory diseases, including MS, NAFLD, T2DM, CVD, chronic kidney disease, and cancer, limonin glucoside consumption may prevent and reverse these chronic diseases.”
Source: Journal of Functional Foods
Volume 12, January 2015, Pages 271–281, doi: 10.1016/j.jff.2014.11.026
“Citrus limonin glucoside supplementation decreased biomarkers of liver disease and inflammation in overweight human adults”
Authors: D.S. Kelley, Y.C. Adkins, S.J. Zunino, et al.