Glutathione S-transferase (GST) assay-guided fractionation of parsley leaf oil from the edible plant Petroselinum sativum Hoffm. (Umbelliferae) led to the isolation of
myristicin.
Myristicin showed high activity as an inducer of the detoxifying
enzyme GST in the liver and small intestinal mucosa of female A/J mice. Reduction of
myristicin yielded
dihydromyristicin that retained the GST-inducing activity.
Myristicin and
dihydromyristicin were tested for their capacity to inhibit
benzo[a]pyrene (B[a]P)-induced
tumor formation in female A/J mice. A 65% inhibition of the
tumor multiplicity in the lung was observed as the result of treatment of
myristicin.
Dihydromyristicin produced small or insignificant reduction of lung
tumor formation. In the forestomach,
myristicin showed a 31% inhibition of
tumor formation; while
dihydromyristicin exhibited a 27% inhibition. Comparison of the structures and activities indicated that the saturation of the isolated double bond in
myristicin resulted in a significant decrease in the inhibitory activity against B[a]P-induced
tumorigenesis. The present results showed that
myristicin, an active inducer of GST activity, is an effective inhibitor of B[a]P-induced
tumorigenesis in mice. Stimulation of GST activity by
myristicin could be a major mechanism for its inhibition of B[a]P or other
carcinogens that may be detoxified in the same manner. As a culinary herb parsley is regularly consumed by humans. Parsley leaf oil is also used extensively for garnishing and seasoning. The results of this study indicate that as a major volatile aroma constituent of parsley
myristicin may be an effective
cancer chemopreventive agent.