Figure 1. Backbone structures of the Ganoderma triterpenoids used in this study.

Backbone A contains two double bonds (Δ⁷,⁸, Δ⁹,¹¹) in the tetracyclic ring and a branch with carboxylic group. Backbone B has one double bond (Δ⁸,⁹) and a branch with carboxylic group. Backbone C has the same double bond (Δ⁷,⁸, Δ⁹,¹¹) in the tetracyclic ring as backbone A but has no carboxylic group on the branch.