Phytochemical studies of Cryptocarya species and their bioactivities / Wan Nurul Nazneem Wan Othman
Phytochemical analysis and bioactivity studies on three species of Lauraceae, Cryptocarya densiflora Blume, Cryptocarya infectoria Miq. and Cryptocarya griffithiana Wight have been conducted. A total of twenty alkaloids were successfully isolated and purified using several chromatographic techniq...
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| Format: | Thesis |
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2017
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| Online Access: | http://studentsrepo.um.edu.my/7655/ http://studentsrepo.um.edu.my/7655/2/All.pdf http://studentsrepo.um.edu.my/7655/4/Wan_Nurul_Nazneem_Wan_Othman_%2D_Thesis.pdf |
| Summary: | Phytochemical analysis and bioactivity studies on three species of Lauraceae,
Cryptocarya densiflora Blume, Cryptocarya infectoria Miq. and Cryptocarya
griffithiana Wight have been conducted. A total of twenty alkaloids were successfully
isolated and purified using several chromatographic techniques such as column
chromatography (CC), thin layer chromatography (TLC) and preparative thin layer
chromatography (PTLC). The structural elucidations were established through several
spectroscopic methods; notably 1D NMR (1H, 13C and DEPT), 2D NMR (COSY,
NOESY, HSQC and HMBC), MS, UV, IR, as well as by comparison with those reported
in the literature. Investigation of the leaves of C. densiflora yielded fourteen alkaloids in
which four of them are new. The new alkaloids were named as prodensiflorin A 126,
prodensiflorin B 127, (-)-densiindolizidine 128 and (-)-desmethylsecoantofine-N-oxide
131, while the known alkaloids were characterized as (-)-antofine 6, (-)-isocaryachine 61,
(+)-reticuline 76, (+)-laurotetanine 86, (+)-N-methyllaurotetanine 87, (+)-nornantenine
123, dicentrinone 124, (+)-oridine 125, (-)-desmethylsecoantofine 130 and crychine 134.
Isolation works on the bark of C. infectoria has resulted six known alkaloids; (+)-Nmethylisococlaurine
14, atherosperminine 15, (+)-reticuline 76, (+)-laurotetanine 86, (+)-
N-methyllaurotetanine 87 and argentinine 135, meanwhile the leaves afforded two
compounds, argentinine 135 and liriodenine 136. Extensive chromatographic purification
on the bark of C. griffithiana has led to the isolation of six known alkaloids; 2-
hydroxyatherosperminine 13, 2-methoxyatherosperminine 72, (+)-reticuline 76, (+)-Nmethyllaurotetanine
87, (+)-nornantenine 123 and argentinine 135. DPPH inhibitory
activity of the four alkaloids from the leaves of C. densiflora was evaluated and compared
to ascorbic acid 137, as the positive control. Alkaloid (-)-desmethylsecoantofine 130
exhibited more effective free radical scavenging with an IC50 value of 62.40 ± 0.05 μg/mL
followed by (+)-N-methyllaurotetanine 87 with an IC50 value of 130.00 ± 0.07 μg/mL. |
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