Structure Elucidation and Biological Evaluation of Secondary Metabolites Isolated from Solanum Surattense and Heliotropium Dasycarpum

Abstract

Natural products or secondary metabolites are usually known as the defensive tools of the host; therefore, certain pharmacological activities are always associated to them so they become a fundamental source of new chemical diversity and an integral component of modern pharmaceutical compilation. Although synthetic drugs share major portion in pharmaceutical industry, but due to high prices of allopathic drugs and their severe side effects, medicinal herbs or their extracts are still the main focus all around the world. Pakistan is rich in indigenous sources comprising medicinal plants but unfortunately there is very less systematic study being done on exploration of these plants for their bioactive secondary metabolites. In the present study, two medicinal plants: Solanum surattense and Heliotropium dasycarpum were selected to look for their secondary metabolites. The whole dissertation comprises six chapters. Chapter 1 provides the background information and importance of Natural Products with their types. It also narrates the drug development process with description of some drugs currently in clinical trials. Information on the role of the genus Solanum on human and phytochemical survey has been discussed in chapter 2. Background information and literature survey of the second plant Heliotropium dasycarpum has been explained in chapter 3. As a part of present research, 16 compounds Solanoid A (1), Solanoid B (2), Solamargine (3), Khasainine (4), Dioscin (5), avenacoside-type saponin (6), β-Sitosterol (7), β-sitosterol-3-O-D-glucopyranoside (8), Stigmasterol (9), Carpesterol (10), Oleanolic acid (11), 5,7-dihydroxy-6,3′,4′-trimethoxyflavon, Eupatilin (12), 5,8-dihydroxy-6,7,4′-trimethoxyflavone (13), 7,4′-dihydroxy-3,5,6-trimethoxy flavone (14), Ferulic Acid (15) and 3,4-dihydroxy cinnamic acid (16) were purified from the methanolic extract of Solanum surattense, and their structural formulae were established due to 1D, 2D NMR and HREIMS techniques. This story with biological screening has been incorporated as Results and Discussion in chapter 4. In the field of natural product, dereplication strategy has brought revolution in rapidly identifying and characterizing the already known compounds from crude extracts, reducing the time required to detect new bioactive compounds and saving chemical resources. Chapter 5 explains about dereplication strategy using molecular networking based on the Mass Spectrometry, it also covers the Results & Discussion section and structural annotation of compounds identified in Heliotropium dasycarpum, from the clusters in molecular network, by the help of spectral libraries. General experimental procedures implied in the whole study are discussed in chapter 6 including chromatographic and spectroscopic techniques, dereplication strategy and generating molecular network along with the protocols for different biological assays.