We have, previously, reported on the HPLC elution behavior of the Th, Pa, U, Np, and Am metallofullerenes and the UV/vis/NIR absorption spectra of the Th@C84 and U@C82 species. In this paper, the followings are reported: (1) Pu metallofullerenes were produced and their HPLC elution behavior was investigated using a radiotracer technique. The HPLC chromatogram of this metallofullerene was found to be almost the same as that of the Np and Am metallofullerenes. (2) The oxidation states of Th@C84 and U@C82 produced in macroscopic quantities were examined by XANES (X-ray absorption near edge structure) measurements. The oxidation state of the U atom in the C82 fullerene cage was estimated to be 3+ with the formal charge of the ionic molecule being U3+@C823-.