Sesquterpenes of genus Petasites

The constituents of Petasites japonicus subsp. giganteus KITAM. (Japanese name: Akita-buki), and the other genus Petasites are reviewed in this paper. Consequently, the structure of new bitter sesquiterpenoids in which the isolations of bakkenolides from the bud of Akita-buki, (local name Bakke), and the mechanism of biosynthesis from an eremophilane skeleton to the novel carbon skeleton (bakkane) as well as total synthesis of bakkenolide-A (B-A) were described. Furthermore, the distribution of bakkenolides from the plants and their bioactive properties are also reviewed.