Nervosin (I) is the anticancer compound extracted from Rabdosia nervosa. Its crystal structure and electronic structure of anticancer-active zone have been given by means of x-ray diffractions and quantum chem. calcns. The crystal structure reveals that in the mol. there is the partly conjugated a-methylenecyclopentanone 5-membered ring, which is a anticancer-active zone owing to its strain. The results of the quantum chem. calcns. reveal that the LUMO of the anticancer-active zone is a pMO with a high energy level. Moreover, the LUMO can easily accept the electron and can easily take part in the chem. reaction. Therefore, nervosin is an electrophilic mol.

Key words: TRADITIONAL CHINESE MEDICINAL HERBS, ANTICARCINOGEN, CRYSTAL STRUCTURE, X-RAY DIFFRACTION ANALYSIS, QUANTUM CHEMISTRY, RABDOSIA, NEORABDOSIN