Title page for ETD etd-06202001-151127

Type of Document Dissertation
Author Berger, John Michael
URN etd-06202001-151127
Title Isolation, Characterization, and Synthesis of Bioactive Natural Products from Rainforest Flora
Degree PhD
Department Chemistry
Advisory Committee
Advisor Name Title
Kingston, David G. I. Committee Chair
Castagnoli, Neal jr. Committee Member
Deck, Paul A. Committee Member
Gandour, Richard D. Committee Member
Tanko, James M. Committee Member
  • Diterpenes
  • Saponins
  • Antineoplastics
  • Anticancer
  • Benzoquinones
Date of Defense 2001-06-04
Availability unrestricted
As part of our ongoing investigations for anticancer drugs from rainforestflora, five plant extracts were determined to contain interesting bioactivity. These extracts were subjected to various separation techniques, affording a number of bioactive compounds that were then characterized by spectral and degradative methods. A methanol extract of Cestrum latifolium Lam. yielded the known compound parissaponin Pb. Hydrolysis afforded its aglycone, the known spirostanol diosgenin. GCMS analysis characterized the derivatized, hydrolyzed sugars.

Previous investigations of Albizia subdimidiata provided two saponins including the new compound albiziatrioside A. The sugar moieties of these two compounds required further characterization. They were characterized by spectral analysis of the partially hydrolyzed products and by GCMS analysis of the hydrolyzed sugars. Pittoviridoside, a saponin from Pittosporum viridiflorum, was isolated in a previous investigation. Further investigation was required to characterize the stereochemical environment of the sugar moiety. The stereochemistries of the pentose sugars were determined by conversion into thiazolidine acetates of known stereochemistries and analysis with standards by GCMS.

Two new diterpenes were isolated from Hymenaea courbaril, which in an earlier investigation provided a new diterpene. The absolute configurations of these diterpenes were assigned on the basis of anisotropic NMR studies, X-ray crystallography, circular dichroism analysis and previously reported literature. A previous investigation of Miconia lepidota isolated two benzoquinones, primin and its n-heptyl analog. Fifteen analogs were synthesized for structure-activity relationship determination. It was found that benzoquinones with moderate-length alkyl side chains displayed the strongest activity in our yeast and cancer cell lines.

  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  Thesis.pdf 1.86 Mb 00:08:37 00:04:26 00:03:52 00:01:56 00:00:09

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.