Japanese scientists have been researching potential cancer preventing compounds in Citrus Lemon, Isodon Japonicus and Lansium Domesticum. Using nuclear magnetic resonance spectroscopy and mass spectrometry the scientists were able to isolate fifty-five chemical compounds of the peels of Citrus Lemon, aerial parts of Isodon japonicus, and leaves of Lansium domesticum. Isodon Japonicus is native to East Asia, its leaves have been known to have antibacterial, anti-inflammatory and anthelmintic properties and used as treatment for stomach cancer. Lansium domesticum is cultivated throughout South East Asia for its fruit although other parts of the plant are also used medicinally to treat malaria and dysentery.
Twenty-one new compounds and thirty-four known compounds were isolated from the three plants which included coumarins, furano-coumarins, oximes, ent-kaurane diterpenoids, and onoceranoid-type triterpenoids. Among these furano-coumarins were singled out for showing the strongest antimutagenic effects in the Ames test. Other results also suggest that oral intake of limonin and lansionic acid (both of which are found in C. limon and L. domesticum) may be beneficial against cancer-causing cells.