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Jie Li-dissertation-Bioactive constituents of Aronia melanocarpa and Sphenostylis marginata ssp. erecta.pdf (14.6 MB)
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Abstract Header
Bioactive Constituents of
Aronia melanocarpa
and
Sphenostylis
marginata
ssp.
erecta
Author Info
Li, Jie
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1387764682
Abstract Details
Year and Degree
2014, Doctor of Philosophy, Ohio State University, Pharmacy.
Abstract
Natural products have played an important role for many decades in drug discovery to combat cancer. As part of a collaborative, multi-disciplinary approach to the discovery of new naturally occurring cancer chemopreventive or chemotherapeutic agents, two edible plants, namely,
Aronia melanocarpa
(black chokeberry) and
Sphenostylis
marginata
ssp.
erecta
(African yellow pea), showed activity in initial hydroxyl radical-scavenging and quinone reductase-induciton screening assays, and thus were selected for further phytochemical and biological investigation. Bioassay-guided fractionation of the ethyl acetate-soluble extract of
A. melanocarpa
fruits, using hydroxyl radical-scavenging and quinone reductase-induciton assays, led to the isolation of a new depside (
81
) and two known depsides (
82
and
83
), along with an additional twenty-one known compounds (
64
-
66
,
70
, and
84
-
100
). Among the known compounds obtained, eighteen compounds (
81
-
87
,
89
,
90
, and
92
-
100
) were isolated from
A. melanocarpa
for the first time. The new compound
81
and the known compounds
82
and
83
represent a novel class of depsides that has been reported only relatively recently. In the present study, the four-bond HMBC correlations of
81
-
83
were obtained to provide direct evidence for fully unambiguous NMR assignments of these three compounds. Among all the twenty-four compounds isolated, seventeen compounds showed significant hydroxyl radical-scavenging activity, with hyperin (
64
, ED
50
0.17 uM) being of the greatest potency. The new compound
81
also exhibited potent antioxidant activity (ED
50
0.44 uM) in this assay. The quinone reductase-induction assay showed that protocatechuic acid (
84
, CD 4.3 uM), neochlorogenic acid methyl ester (
96
, CD 6.7 uM), and quercetin (
99
, CD 3.1 uM) doubled quinone reductase activity at concentrations less than 10 uM. The chloroform-soluble extract of the root bark of
S.
marginata
ssp.
erecta
was also fractionated under the guidance of both hydroxyl radical-scavenging and quinone reductase-induciton assays, and resulted in the isolation of sphenostylisins A-C (
107
-
109
), three complex dimeric compounds representing two novel carbon skeletons, as well as an additional eight new compounds, sphenostylisins D-K (
110
-
117
). All these new compounds obtained were evaluated against a panel of
in vitro
bioassays. Of these isolates, eight compounds (
107
-
110
and
114
-
117
) exhibited potent hydroxyl radical-scavenging activity (ED
50
values range from 0.60 to 2.6 uM). Six compounds (
107
-
110
,
114
, and
115
) showed quinone reductase-inducing activity, with sphenostylisin C (
109
, CD 2.1 uM) being the most potent. Eight compounds (
107
-
114
) showed NF-kB p65 inhibitory activity. In particular, sphenostylisin A (
107
), representing a novel carbon skeleton, was found to be a very potent NF-kB p65 inhibitor with an IC
50
value of 6 nM. This compound (
107
) also showed cytotoxicity (IC
50
1.6 uM) against the HT-29 cell line. Based on the structural features and similarities of these eleven new compounds (
107
-
117
), a plausible biogenetic pathway and a preliminary structure-activity relationship among them were discussed in the present study. In summary, considering the high abundance and potent activities of bioactive constituents present in
A. melanocarpa
and
S.
marginata
ssp.
erecta
, these two plants can be regarded as excellent sources of lead compounds for the development of drugs to combat cancer.
Committee
A. Douglas Kinghorn (Advisor)
Pages
287 p.
Subject Headings
Pharmacy Sciences
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Li, J. (2014).
Bioactive Constituents of
Aronia melanocarpa
and
Sphenostylis
marginata
ssp.
erecta
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387764682
APA Style (7th edition)
Li, Jie.
Bioactive Constituents of
Aronia melanocarpa
and
Sphenostylis
marginata
ssp.
erecta
.
2014. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1387764682.
MLA Style (8th edition)
Li, Jie. "Bioactive Constituents of
Aronia melanocarpa
and
Sphenostylis
marginata
ssp.
erecta
." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387764682
Chicago Manual of Style (17th edition)
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Document number:
osu1387764682
Download Count:
1,165
Copyright Info
© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.