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Structural and synthetic studies of bioactive natural products

Bioassay directed fractionation of the methyl ethyl ketone extract of Crescentia cujete resulted in the isolation of nine bioactive compounds, and detailed spectroscopic interpretation led to the assignment of their structures as (2S,3S)-3-hydroxy-5,6-dimethoxy dehydroiso-α-Iapachone [2.10], (2R)-5,6- dimethoxydehydroiso-α-Iapachone [2.11], (2R)-5-methoxy dehydroiso-alapachone [2.12], 5-hydroxy-2-(1'-hydroxyethyl)naphtho[2,3-b ]furan-4,9-dione [2.13], 2-(1 '-hydroxyethyl)naphtho[2,3-b ]furan-4,9-dione [2.14]' 2-isopropenylnaphtho[ 2,3-b ]furan-4,9-dione [2.15], 5-hydroxydehydro-iso-a-Iapachone [2.16], 3-hydroxymethylfuro[3,2-b ]naphtho[2,3-d]furan-5,10-dione [2.17], and 9- hydroxy-3-hydroxymethylfuro[3,2-b ]naphtho[2,3-d]furan-5,10-dione [2.18]. Compounds 2.10-2.12 are new, showing selective activity towards DNA repair-deficient yeast mutants. The selective DNA damaging activity of known compounds 2.13-2.16 is reported herein for the first time. Compounds 2.17 and 2.18 also show DNA damaging activity, and possess a novel fused ring system.

The bioactive sterols ergosta-5-24(28)-diene-3β,7α-diol [3.1] and 24,28- epoxyergost-5-ene-3β,7α-diol [3.2], originally isolated from <i>Pseudobersama mossambicensis</i>, have been synthesized from stigmasterol. In addition to these sterols, some of their analogs were prepared, and the bioactivity of all compounds were assessed. / Ph. D.

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/40067
Date21 October 2005
CreatorsHeltzel, Carl E.
ContributorsChemistry, Kingston, David G. I., Bell, Harold M., Castagnoli, Neal Jr., Merola, Joseph S., Taylor, Larry T.
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeDissertation, Text
Formatxii, 148 leaves, BTD, application/pdf, application/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
RelationOCLC# 30698161, LD5655.V856_1993.H459.pdf

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