Development of a method for the quantification of D-glucaric acid in different varieties of grapefruits by high-performance liquid chromatography and mass spectra

Grapefruits were found to contain D-glucaric acid, which has anticancer properties. In the present investigation, a method has been developed for the quantification of D-glucaric acid in grapefruit by high-performance liquid chromatography (HPLC) using a simple isocratic mobile phase with detection at 210 nm. Grapefruit samples were homogenized, centrifuged and filtered through a 0.45 microm membrane and injected into a HPLC system. The developed method was used for the quantification of D-glucaric acid in nine widely used grapefruit varieties. Furthermore, the identity of D-glucaric acid was confirmed by mass spectra. Seasonal variation of D-glucaric acid within the individual varieties were also measured in fruits harvested during November, February and May. The overall trend of D-glucaric acid level was increased from early to late season fruits. The developed method has a sensitivity of D-glucaric acid as low as 0.05 microg with an accuracy and precision >95%. This method was found to be simple, fast, accurate and reproducible. Moreover, the identity of D-glucaric acid was confirmed by mass spectra. Additionally, the labor intensity and cost of sample preparation were greatly reduced as compared to reported methods. This is the first report on quantification of D-glucaric acid in different varieties of grapefruits from three harvesting sessions.

Urinary D-glucaric acid, a marker substance for microsomal enzyme induction. Methodological aspects, responses to alcohol and findings in workers exposed to toluene

D-glucaric acid, an end product of glucuronic acid metabolism, has been used as a marker substance for microsomal enzyme induction. In this study a convenient microtitre-plate based method for the quantification of urinary D-glucaric acid has been developed and validated. Mean urinary D-glucaric acid excretion in 20 health humans as measured by this method was 3.2 mumol glucaric acid mmol-1 creatinine, 95% confidence interval 3.0-3.4. Moderate alcohol consumption in 18 healthy volunteers did not significantly augment the urinary D-glucaric acid excretion. Occupational exposition to toluene in a printing plant was investigated. In spite of considerable intra- and inter-individual variability, a significant difference between exposed (3.5, 3.1-3.9) and non-exposed (2.6, 2.2-3.0) workers was observed, p < 0.025. We conclude that the measurement of D-glucaric acid can be utilized for biological screening of enzyme induction on a group basis.

Potential use of D-glucaric acid derivatives in cancer prevention

There is now growing evidence from animal models for the possible control of different stages of the carcinogenic process by the beta-glucuronidase inhibitor D-glucaro-1,4-lactone and its precursors such as D-glucaric acid salts, D-glucarates. D-Glucaric acid is a natural, non-toxic compound produced in small amounts by mammals, including humans. It was recently found in some vegetables and fruits. D-Glucaro-1,4-lactone and D-glucarate exhibit potent antiproliferative properties in vivo. Some human subpopulations could have reduced risk of cancer development by ingesting food rich in D-glucaric acid or self-medication with D-glucarates alone or in combination with other chemopreventive agents.