I= STUDIES IN THE CHEMICAL CONSTITUENTS OF ERIGERON CANADENSIS (CONYZA CANADENSIS) AND BERCHEMIA PAKISTANICA
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Title of Thesis
STUDIES IN THE CHEMICAL CONSTITUENTS OF ERIGERON CANADENSIS (CONYZA CANADENSIS) AND BERCHEMIA PAKISTANICA

Author(s)
Naveen Mukhtar
Institute/University/Department Details
International Center for Chemical Sciences University of Karachi/H.E.J Research Institute of Chemistry
Session
2004
Subject
Chemistry
Number of Pages
246
Keywords (Extracted from title, table of contents and abstract of thesis)
erigeron canadensis (conyza canadensis), berchemia pakistanica, genus conyza, sphingolipids, healing properties, medicinal plants, sphingolipids

Abstract
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 hundreds of new natural products possessing promising potentials for the treatment of serious human ailments like aids, 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 parts 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 Canadensis 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 material 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.

Known Compounds from Erigeron Canadensis β-Sitosterol 171 Stigmasterol 172 β-Sitosterol 3-O- β-D-glucopyranoside 173 Harmine 174 p-Hydroxybenzoic acid 175 3,5-Dihydroxybenzoic acid 176 3,5-Dimethoxybenzoic acid 177 3 β-Hydroxyolean-12-en-28-oic acid 178 3 β-Erythrodiol 1879

“Studies in the Chemical Constituents of Berchemia Pakistanica Browicz” Phytochemical studies on the methanolic extract of the whole plant material have resulted in the isolation and structural elucidation of four new compounds along with nine other compounds reported for the first time from this species.

Known Compounds from Berchemia Pakistanica 7.5’-Dimethoxy-3,5,2’-trihydroxyflavone 235 4’,5-Dihydroxy-3,6,7-trimethoxyflavone 236 5,6-Dihydroxy-4,7-dimethoxy-2-methylanthracene-9,10-dione 237 1,3,4-Trihydroxy-6,7,8-trimethoxy-2-methylanthracene-9,10-dione 238 β-Sitosterol 239 β-Sitosterol 3-O- β-D-glucopyranoside 240 Vavain 241 Daphnin 242 Daphnetin 8-O- β-D-glucopyranoside 243

Pharmacological screening of sphingolipids 166-170 revealed significant tyrosinase inhibiting activity of 167,moderate tyrosinase inhibiting activity in 166,169 and 170,while 168 was inactive. Pakistolides A 231 and B 232 showed significant inhibitory activities against lipoxygenase and a-glucosidase enzyme. In addition, Pakistolide B 232 also revealed strong antioxidant activity. Berchemins A 233 and B 234 showed strong glipoxygenase inhibiting activity. The latter also showed strong inhibition against a-glucosidase while former was moderately active.

From these findings it is obvious that all of the newly isolated compounds except 168 have potentials to be used in the treatment of skin diseases, human-immunodeficiency virus (HIV), tumor, bronchial asthma and inflammation.

Download Full Thesis
1973.82 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
174.26 KB
2 1 Introduction 2
506.32 KB
  1.1 General Introduction f the Genus Conyza 3
  1.2 Sphingolipids 30
  1.3 Biosynthesis of Sphingolipids 39
  1.4 Biological Activity of Sphingolipids 50
  1.5 Functions of Sphingolipids 54
  1.6 Applications of Sphingolipids 55
3 2 Results and Discussion 58
416.34 KB
  2.1 Pharmacological Screening of Conyza Canadensis 59
  2.2 Phytotoxic Bioassay 60
4 3 Experimental 109
221.59 KB
  3.1 General Experimental Conditions 110
  3.2 Plant Material 111
  3.3 Extraction, Fractionation and Isolation 112
  3.4 Determination of Biological Activities 133
  3.5 Enzyme-Inhibition Assay 134
5 4 References 136
117.83 KB
6 5 Introduction 148
176.97 KB
  5.1 General Introductionof the Genus Berchemia 149
  5.2 Biosynthesis 158
7 6 Results and Discussion 170
397.95 KB
  6.1 Pharmacological Screening of Berchemia Pakistanica 171
  6.2 Phytochemical Studies on Berchemia Pakistanica 173
8 7 Experimental 216
196.03 KB
  7.1 General Experimental Conditions 217
  7.2 Plant Material 217
  7.3 Extraction, Fractionation and Isolation 217
  7.4 Determination of Biological Activities 236
  7.5 Enzyme-Inhibition Assays 237
9 8 References
70.24 KB
  8.1 References 240
  8.2 Research Articles 246