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The work embodied in the dissertation covers the isolation and characterization of chemical constituents obtained from three members of the family Lamiaceae with their possible biological studies. The isolated constituents were either new or previously reported in the literature from other sources. They were characterized via various sophisticated spectroscopic techniques available at International Center for Chemical and Biological Sciences (ICCBS), University of Karachi. The dissertation is divided into four chapters: The first chapter is a general article entitled, "Hidden Wealth of Natural Drugs" describing the use of medicinal plants as drugs for human health with specific reference to Greeks and Chinese. This chapter is divided into two sections. The first section describes the challenges for new century regarding the natural products as medicines while the second section covers the highlights of the family Lamiaceae including economic and pharmaceutical uses of common Lamiaceous plants. Keeping in mind the role of diterpenoids in drug discovery, this class of natural products is also included in the same chapter due to the fact that this family is famous for this specific class. The following three members of the family Lamiaceae were investigated for the search of new chemical constituents and their details are described in the following chapter-2, 3 and 4. The three investigated plants are: Leonurus cardiaca L. Nepeta crassifolia Boiss. & Buhse Salvia nubicola Wall. ex Sweet. The second chapter entitled, "Chemical and Biological Studies on Leonurus cardiaca L.� deals with the chemical and biological studies of titled plant. L. cardiaca was collected from Iran. As a result of this study, no new constituent was obtained. However, seven known pentacyclic triterpenes of ursane and lupine classes and a flavone were characterized spectroscopically. All the isolated triterpenes have not been reported so far from our investigated source. The isolated ursane based triterpenes were also tested for their respiratory burst and superoxide scavenging ability and the results are given in the same chapter. The medicinal features of genus Leonurus and L. cardiaca together with botanical descriptions of titled source are included in this chapter. The third chapter entitled, “Chemical Studies on Nepeta crassifolia Boiss. & Buhse� deals with the isolation and characterization of three new constituents namely crassifone (1), crassifoate (2) and crassifol (4) along with six known constituents. N. crassifolia was also collected from Iran. The biological and medicinal features of the genus Nepeta and botanical descriptions of N. crassifolia are also included in this chapter. -----------------------------------------------------------Snap--------------------------------------------------------------- The fourth and last chapter of this dissertation entitled, “Chemistry of Salvia nubicola Wall. ex Sweet.� describes the characterization of five new secondary metabolites. These include four sesquiterpenoid-Iactones of guiane class [nubiol (1), bisnubdiol (2), nubenolide acetate (3), nubenone (4)] and a ceramide [nubenamide (5)]. In addition to chemistry, the isolated constituents were also screened for antibacterial and phytotoxic properties. Structures of compounds 2-5 were elucidated by means of 20 NMR while 1 was characterized via single crystal X-ray crystallography. The biosyntheses of guaianolides and ceramides are also given in the same chapter. S. nubicola was collected from Quetta (Pakistan). This chapter also covers the important features of the genus Salvia including botanical descriptions, biological and medicinal features, chemical literature survey and various diterpenoidal skeletal found in this genus. -----------------------------------------------------------Snap--------------------------------------------------------------- During the phytochemical investigations, altogether eight new and fifteen known constituents were obtained from three members of the family Lamiaceae. Structures of all the isolated metabolites were elucidated with the aid of sophisticated 2D NMR techniques and single crystal X-ray crystallography. As a result of these investigations, two papers have been published and four are in press for publication. In the end of the dissertation, a list of publications (of S.A.I.) and relevant published papers (to-date) are included. It is to clarify here that each chapter has its separate schemes, tables, figures and compounds numbers. Highlights of biosyntheses related to the obtained constituents, chemical literature survey of corresponding source and references are also presented in each chapter independently.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: leonurus cardianca, nepeta crassifolia, salvia nubicola, lamiaceae, natural drugs, medicinal plants, diterpenoids
Subjects: Q Science > QD Chemistry
Depositing User: Muhammad Khan Khan
Date Deposited: 07 Sep 2016 03:54
Last Modified: 07 Sep 2016 03:54

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