The 2011 ASHS Annual Conference

Citrus fruits are a rich source of furocoumarins and polymethoxyflavones (PMF’s) which have demonstrated several biological activities. Considering the need for both animal and human clinical trials, large scale separation and purification of these compounds is essential.  In the present study, a simultaneous separation of furocoumarins and PMF’s from citrus grapefruit byproducts was developed. Cold pressed citrus peel oil was subjected to silica column chromatography to separate the oil and waxes. The remaining defatted constituent was collected by eluting with acetone. The enriched extract was subjected to separation on a silica gel column flash chromatography using a step gradient of hexane and acetone solvents. The flow rate was maintained at 60 mL/min for a run time of 45 min. Separation of peaks were monitored at 210 and 340 nm and the separated peaks were collected in fractions. These fractions were analyzed by HPLC, pooled and concentrated resulting in isolation of two furocoumarins (bergamottin- 1.53 g; 0.8 % yield and bergapten- 59 mg; 0.03 % yield) in gram level quantity and three PMF’s (tangeretin- 41 mg; 0.02 % yield, heptamethoxyflavone- 64 mg; 0.03 % yield  and nobiletin- 31 mg; 0.02 % yield) in milligrams quantity. The purity and identity of the isolated compounds was confirmed by spectral analysis using HPLC and NMR. The flash chromatography method was tested to be repeatable with low % RSD yield of the separated compounds. Utilization of simultaneous isolation method for isolation of value added products from citrus grapefruit byproducts could be beneficial to the citrus processing industry. To the best of our knowledge this is the first report on separation of furocoumarins and PMF’s from grapefruit byproducts using flash chromatography.

The present research report is based on work supported by the “Designing Foods for Health” through USDA CSREES Grant # 2010-34402-20875.