Abstract:Two antitumor active diterpenoids, yunnancoronarin C and yunnancoronarin A, were isolated from the rhyzome of Hedychium yunnanense Gagnep. The former is a new compound, whose structure was deter- mined by spectra and chemical methods. Yunnancoronarin C could also be obtained from photosensitized oxidation of yunnancoronarin A as a minor product.