Studies On The Active Constituents Of Cortex Albizziae

Cortex Albizziae, the stem bark of the leguminous plant Albizzia julibrissin Durazz., was specified in Chinese Pharmacopoeia as a traditional Chinese medicine used to relieve melancholia and uneasiness, invigorate the circulation of blood and subside a swelling. It was reported that a series of lignan glycosides isolated from the plant would be responsible for the pharmacological activities as a tonic. The investigation was, therefore, carried out in aim of discovering leading compounds or structures.80% EtOH extract of Cortex Albizziae was partitioned between CHCl3, EtOAc and n-BuOH respectively with water to give four fractions. The n-BuOH fraction was then subjected to a high porous polymer HP-20 column, giving three fractions: AJ-B-1, AJ-B-2 and AJ-B-3. Almost all the triterpenoid glycosides, the major components in the polar extract of Cortex Albizziae, were in AJ-B-2, while most of lignan glycosides were richened in AJ-B-1. Therefore, the lignan and triterpenoid glycosides were separated successfully with HP-20 column chromatography. Furthermore, an effective isolation route of AJ-B-1 was determined as follows: silica gel column chromatography (c.c.) βC18 c.c. - Sephadex LH-20 gel c.c. or preparative TLC, along with seven compounds were obtained. In addition, CHCl3 fraction was isolated to give six compounds. In summary, thirteen compounds have been obtained and identified by means of chemical and spectral methods (ESI-MS/MS,EI-MS,NMR,IR), as follows: (-)-syringaresinol-4,4'-bis-O-βD-glucopyranoside(Ⅰ), icariside E5(Ⅱ), 5,5'-dimethoxy-7-oxolariciresinol-4'-O-βD-apiofuranosyl-(l→2)-βD-glucopyranoside(Ⅲ), vomifoliol-3'-O-βD-apiofur anosyl-(l-6)-p-D-glucopyranoside(Ⅳ), 3,4,5-trimethoxyphenol-l-O-βD-apiofurano syl-(l-2)-βD-glucopyranoside(Ⅴ), glaberide I 4-O-βD-apiofuranosyl-(l-2)-βD-glucopyranoside(Ⅵ), Julibrine A(Ⅶ), l-octacosanol(Ⅷ), lup-20(29)- en-3-one (Ⅸ), lupeol(Ⅹ), a-spinasterol(Ⅺ), a-spinasterone(Ⅻ) and βsitosterol(XIII). Among them, Ⅶ is a new compound, Ⅷ,Ⅸ and Ⅹ were obtained from Cortex Albizziae for the first time.As ACPI came forth in 1990's, LC-MS developed into a grown-up analysis means and was applied widely in the field of pharmaceutical chemistry. Methodology was explored in this thesis for the application of LC-MS and MS/MS on phytochemicalisolation and identification. It was proved that ESI-MS/MS was a ideal rapid-analysis method, especially for glycosides, by giving relative molecular weights and some important fragments, to characterize known and unknown compounds, and finally help to identify the structures.The anti-inflammatory activities of the obtained fractions were evaluated by the inflammation model of Kunming male rat ears induced by croton oil. The results showed that n-BuOH fraction was as effective as, or better than the positive contrast Leigongteng Glycosides. AJ-B-1 showed significant anti-inflammatory activity and exhibited a dose-dependent relationship in a dose of 5 to 20 mg-kg-1. The activities of compounds obtained were not tested for the lack of sufficient sample amount.