Volume 37 will provide details on the major chemical constituents of medicinal plants and their mechanism of action as the anticancer compounds. This special issue, in addition to the previous volume (volume 36 of The Enzyme series was on Natural Products and Cancer Signaling Targets: Isoprenoids, Polyphenols and Flavonoids), will highlight the significant advance made in the field in elucidating mechanisms of anticancer effect of the major phytochemicals.