Dissertation summary: Study on the isolation, chemical transformation and biological activities of triterpenoids from Centella asiatica (L.) Urban (Apiaceae)

The aims of the dissertation are: Isolation and purification of the main chemical constituents of the plant Centella asiatica (L.) Urban collected from various regions in Vietnam; synthesis of new derivatives of asiatic acid and madecassic acid obtained from C. asiatica.
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Dissertation summary: Study on the isolation, chemical transformation and biological activities of triterpenoids from Centella asiatica (L.) Urban (Apiaceae) VIETNAM ACADEMY OF SCIENCE AND MINISTERY OF TECHNOLOGY EDUCATION AND GRADUATE UNIVERSITY OF SCIENCE AND TRAINING TECHNOLOGY VO THI QUYNH NHU STUDY ON THE ISOLATION, CHEMICAL TRANSFORMATION AND BIOLOGICAL ACTIVITIES OF TRITERPENOIDS FROM CENTELLA ASIATICA (L.) URBAN - (APIACEAE) Scientific Field: Organic Chemistry Classification Code: 62 44 01 14 DISSERTATION SUMMARY HA NOI - 2017 The dissertation was completed at: Institute of Chemistry Vietnam Academy of Science and Technology Scientific Supervisors: 1. Prof. Dr. Sc. Tran Van Sung Institute of Chemistry - Vietnam Academy of Science and Technology 2. Dr. Tran Van Loc Institute of Chemistry - Vietnam Academy of Science and Technology 1st Reviewer: ............................................................................................................. .............................................................................................................. .............................................................................................................. nd 2 Reviewer: ............................................................................................................ .............................................................................................................. .............................................................................................................. 3rd Reviewer: ............................................................................................................. .............................................................................................................. .............................................................................................................. The dissertation will be defended at Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay District, Ha Noi City. At ….. hour….. date….. month …..2017. The dissertation can be found in National Library of Vietnam and the library of Institute of Chemistry, Vietnam Academy of Science and Technology. I. INTRODUCTION 1. Background Nowadays, it is necessary to search for interesting active compounds and develop them to new drugs. Besides active natural products, study on synthesis of active derivatives from compounds isolated from plant sources is one of the most effective ways to search for interesting active compounds. Centella asiatica (L.) Urban (Apiaceae) is a tropical medicinal plant native to South and Southeast Asian countries including Vietnam. This plant has been reported to own a wide range of biological activities such as wound healing, anti- inflammatory, antipsoriatic, antiulcer, hepatoprotective, anticonvusant, sedative, immunostimulant, cardioprotective, antidiabetic, cytotoxic, antitumor, antiviral, antibacterial, anti-insecticidal, antifungal, and antioxidant activities. It also has been used for the treatment of lepra and venous deficiencies. The plant Centella asiatica contains several classes of natural substances, but triterpenes are its major and most important constituents, which are regarded as marker components in terms of quality control. Among the triterpenoids of C. asiatica , four compounds with the ursane triterpene skeleton, asiatic acid, madecassic acid, asiaticoside and madecassoside, play the most important role. In view of the high content of these biological active compounds in C. asiatica, many chemical modifications of their structure have been carried out in order to find more active substances with potential pharmaceutical uses. For the above reasons, we propose the dissertation: “Study on the isolation, chemical transformation and biological activities of triterpenoids from Centella asiatica (L.) Urban (Apiaceae)”. 2. Objectives of the dissertation The aims of the dissertation are: 1. Isolation and purification of the main chemical constituents of the plant Centella asiatica (L.) Urban collected from various regions in Vietnam . 2. Synthesis of new derivatives of asiatic acid and madecassic acid obtained from C. asiatica. 1 3. Determination of the biological activities of the synthesized derivatives to find new biologically active substances, and exploration of their structure - activity relationship. 3. New contributions of the dissertation  Quantitative determination of two main triterpenoids, asiatic acid and madecassic acid in three Centella asiatica samples collected in Son Tay (Hanoi), Nam Dinh province and Ho Chi Minh city was performed using column chromatography and HPLC. It was found that the content of both triterpenes in the Son Tay sample was the highest with values of 0.72% and 0.89% (of dry material) for asiatic acid and madecassic acid, respectively. This sample was chosen for extraction of these two triterpenes for chemical transformation.  The liver-protective activity of asiatic acid in the paracetamol-induced hepatotoxicity model in mice was evaluated. Asiatic acid showed a significant liver-protective activity (P4. The layout of the dissertation The dissertation consists of 136 pages and contains 124 references. The layout of the dissertation includes the following sections: Preface (1 pages), Chapter 1: Overview (32 pages ...