title: Stability and structure studies on alisol a 24-acetate.
abstract: Alisol A 24-acetate is one of the main active triterpenoid compounds isolated from Rhizoma Alismatis, which is a famous Traditional Chinese Medicine, and has been determined for the quality control of this crude drug. In this study, alisol A 24-acetate was found to be unstable in solvents and its stability in different solvents was investigated in detail. The results showed that alisol A 24-acetate and 23-acetate inter-transformed in solvents and the transformation rate was more rapid in protic solvents than in aprotic solvents. Moreover, both alisol A 24-acetate and 23-acetate were deacetylated to yield alisol A when kept in methanol for a long time. This is the first report on the structural transformation between alisol A 24-acetate, alisol A 23-acetate and alisol A. In addition, the single crystal X-ray structure of alisol A 24-acetate and the NMR data of alisol A 23-acetate were also reported for the first time.
authors.affiliation: Department of Natural Medicines and the State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, People's Republic of China.
authors.forename: Bolat
authors.initials: B
authors.lastname: Makabel
authors.forename: Yuying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Yanjing
authors.initials: Y
authors.lastname: Bai
authors.forename: Qingying
authors.initials: Q
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Wu
authors.forename: Yang
authors.initials: Y
authors.lastname: Lv
mesh_terms: D034901:Alismataceae / Q000737:chemistry; D002783:Cholestenones / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry; D027343:Rhizome / Q000737:chemistry; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D002783:Cholestenones; D014315:Triterpenes; C457233:alisol A 24-acetate