Are Isoursenol and γ-Amyrin Rare Triterpenes in Nature or Simply Overlooked by Usual Analytical Methods?
                                
                                    
                                        作者:Hui Shan、William K. Wilson、Dorianne A. Castillo、Seiichi P. T. Matsuda                                    
                                    
                                        DOI:10.1021/acs.orglett.5b01851
                                    
                                    
                                        日期:2015.8.21
                                    
                                    Among pentacyclic triterpenes commonly found in plants, gamma-amyrin and isoursenol are seldom reported and considered rare in nature. It was hypothesized that these triterpenes are instead routinely overlooked due to inadequate spectral characterization. gamma-Amyrin was prepared by HCOOH isomerization of alpha-amyrin, and isoursenol was isolated from products of a heterologously expressed oxidosqualene cyclase. With precise NMR and GC-MS data, a metabolomics strategy was used to identify isoursenol and gamma-amyrin in a wide range of plants.