The art of healing has its origin in the antiquity of human civilization. Even in prehistoric times, the man was fully able to distinguish those plants, which had healing properties from those having toxicities. Great reservoirs of knowledge on medicinal plants have been provided by Chinese, Sumerian, Babilonian, Egyptian, Greek, and Muslim civilizations. In the indo-Pakistan subcontinent records of the indigenous system of medicine known as Ayurveda, go back to 700 B.C., and its systematization is attributed to charaka and susruta, who have cited about seven hundred medicinal plants.
In Indo-Pakistan subcontinent, there has been a fairly organized effort for pharmacological studies in the physiologically active plant constituents. Various centers have been established in both India and Pakistan for systematic studies on medicinal plants. The most recent and sophisticated amongst these is H.E.J research Institute of Chemistry, University of Karachi, where bioassay directed isolation studies of active plant constituents are routinely carried out. These studies have already resulted in hundred of new natural products possessing promising potentials for the treatment of serious human ailments like aids, cancer tumor, diabetes, hypertension, etc.
The present thesis describes the bioassay directed isolation studies of bioactive natural products from two medicinal plants namely Erigeron Canadensis (syn. Conyza Canadensis) and Berchemia Pakistanica. Both of these occur in southern part of Pakistan and are used by local physicians for the treatment of a variety of ailments. The thesis is , therefore, presented in two parts namely.
Part-A Studies in the chemical constituents of erigeron Canadensis (syn. Conyza linn)
Part-B Studies in the chemical constituents of berchemia Pakistanica browicz
“Studies in the chemical constituents of erigeron Canadensis (syn. Conyza Canadensis linn.)”
Phytochemical studies on the methanolic extract of the whole plant materials have resulted in the isolation and structural elucidation of five new sphingolipids along with nine other compounds reported for the first time from this species.