Development and Validation of a Novel Assay to Quantify D-Limonene in Human Adipose Biopsies

Abstract

d-Limonene is a lipid-soluble bioactive food component found in citrus peel. It has demonstrated strong chemopreventive effects in rodent mammary, gastric, skin, liver, and lung cancers and is correlated with a significantly reduced risk for human squamous cell skin carcinoma. Because d-limonene is fat-soluble, it may have enhanced chemopreventive activity in fatty tissues such as breast. No previous methodology to quantify d-limonene in the adipose had been developed which significantly limited d-limonene tissue distribution research. For this research, an assay to extract d-limonene from adipose tissue and quantify with GC/MS was developed and validated. Linear calibration curves were established over the range of 0.0-2,526 ng d-limonene. Extraction recovery was 80%. Satisfactory within day precision (RSD 6.75 to 9.56%) and accuracy (% difference of 2-4%) were achieved. This sensitive, accurate, and precise assay to quantify d-limonene in adipose can be used for future human or animal fatty tissue deposition studies.