The petrol extract of the whole plant of Adiantum lunuactum yielded a new hopane triterpenoid characterized as 6alpha-acetoxy-16beta,22-dihydroxy-3-ketoisohopane, along with the known 3beta,6alpha,16beta,22-tetrahydroxyisohopane (mollugogenol A). The structures were elucidated by spectral as well as chemical studies. (C) 2002 Elsevier Science B.V. All rights reserved.