IDENTIFICATION OF CYTOCHROME P450 3A4 PRESENT IN CHO CELLS TREATED WITH A CITRUS HYBRID

Abstract

Orangelo or best known as ‘Chironja’ is a hybrid citrus fruit between orange and grapefruit. Previous investigations agree that different compounds found in citrus fruits like orange and grapefruit inhibit, completely or partially, the activity of different isoenzymes in the cytochrome P450 system. These compounds are ascorbic acid, flavonoids, limonoids, furocoumarins and other related complexes. The effect of this hybrid in the P450 system of Chinese Hamster Ovarian Cells, especially in CYP3A4 isoenzyme was studied. Extraction from the fruit was performed by squeezing three chironjas. CHO cells were treated for 48 hours with the chironja's extract. After this procedure the luminescence of each sample was determined using an appropriate luminescent compound. Intensity was measured at 450 nm using a spectrofluorometer. Results were: 0.827 pmol d‐luciferin/ pmol/min., 2.44 pmol d‐luciferin/pmol/min., and 1.26 pmol d‐luciferin/pmol/min., control, organic extract and treated cells, respectively. An increase on enzyme activity was observed. Further studies are being conducted in order to establish the effect of this extract on the isoenzyme.