Study On The Chemical Constituents Of The Seeds Of O.fragrans And The Whole Plants Of P.alkekengi Var.francheti

The search for lead compounds with important biological activities from natural origins remains one of the most important approaches in modern drug discovery, and traditional medicinal plants or folk herbs have proved to be very important sources. In this thesis, chemical studies on the seeds of Omanthus fragrans and the whole plants of Physalis alkekengi var. francheti were conducted by using various chromatographic techniques for the isolation of their chemical constituents and spectroscopic methods for the structural elucidation. The chromatographic techniques used include chromatography of D101 macroporous resin, MCI gel column, normal phase silica gel column, C18 reversed-phased silica gel column, and Sephadex LH-20 column. The methods applied in the structural elucidation include nuclear magnetic resonance (NMR), mass spectroscopy (MS), infrared spectroscopy (IR), ultraviolet spectroscopy (UV), and specific optical rotation. As a result, fourteen compounds have been isolated from the two plants, and two of them are new compounds. The biological evaluations of these natural products are in progress.Part 1: Study on the chemical constituents of the seeds of Omanthus fragrans.The flowers, fruits and roots of O. fragrans, a species of the Oleaceae family, have been widely used in the TCM or folklore medicine to treat liver and stomach pains. Chemical study on the seeds of O. fragrans collected at the campus of Guangxi Normal University has led to the isolation of six known compounds. The structures of these compounds were identified to be oleanolic acid (1),β-sitosterol (2), stigmasterol (3),β-Sitosterol-3-glucoside (4), (8E)-Nüzhenide (5), and secoiridoid glucoside GL3 (6) by comparison of their 1H-NMR, 13C-NMR, MS (ESI-MS, EI-MS) data with those reported in the literature, or by comparison of their Rf values and melting points with the authentic compounds. Of all these compounds, oleanolic acid (1) was shown to possess the anti-hepatitis activity as reported in the literature; (8E)-Nüzhenide (5), and secoiridoid glucoside GL3 (6) are iridoids with, respectively, two glycoside and three glycoside moieties. The two iridoids are the most abundant compounds in the plant and were shown to be the main constituents of the seeds of O. fragrans. All these compounds except oleanolic acid (1) were isolated from this plant for the first time.Part 2: Study on the chemical constituents of the whole plants of Physalis alkekengi var. francheti P. alkekengi var. francheti is a genus belonging to the Solanaceae family. The roots, whole plants, or sepal have been used to treat the throat pain and cough. Chemical study on the whole plants of P. alkekengi var. francheti colleted in Guangxi Zhuang Autonomous Region has led to the isolation of two new steroids and six known compounds. The structures of the two new steroids, physalin W (7) and withalkekengin (13), were elucidated by extensive analysis of their 1D (1H and 13C-NMR) and 2D-NMR (HSQC, HMBC, and NOESY) spectra as well as their ESI-MS, LREI-MS, HREI-MS, IR, UV, and optical rotation. One of the two new compounds, physalin W (7), was among the withanolide steroids that possessed the most advanced biogenetic oxidation level, while another new compound, withalkekengin (13), is a withanolide that has a chlorine atom which is rarely found in the compounds isolated from the Solanaceae family. The structures of the known compounds were identified to be physagulin B (8), withangulatin A (9), physlin I (10), withaminimin (11), physagulin J (12) and 3β, 24ξ-dihydroxy-ergosta-5, 25-dienolide (14) with those reported in the literature. All compounds are withanolides except 3β, 24ξ-dihydroxy-ergosta-5, 25-dienolide (14). All these compounds were isolated from this plant for the first time.To summarize, the chemical constituent studies of the seeds of O. fragrans and the whole plants of P. alkekengi var. francheti have afforded a series of secondary metabolites, which would form a basis for the exploitation and utilization of O. fragrans and P. alkekengi var. francheti...