• Korean Journal of Pharmacognosy
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• v.1 no.1
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• pp.3-17
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• 1970

Diterpenoids contain only 20 carbon atoms, and the plants that have been examined for diterpenoids are less numerous. However, a greater variety of the possible cyclization and oxidation patterns has been observed in the diterpenoids. Thus the list of known structures is large. The diterpenoids have often been found in two antipodal forms. Our present state of knowledge does not allow us to draw any conclusions from the distributions of these configurations.

• Korean Journal of Pharmacognosy
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• v.1 no.2
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• pp.1-10
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• 1970

The cyclization of geranylgeranyl pyrophosphate followed by ionization, proton elimination or cation center migration produces dicyclic, tricyclic and tetracyclic diterpenoids. The role of some of diterpenoids in animals is well known but their precise functions in plants remain to be explained.

• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.513-519
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• 2012

Although the immense efforts have been made for cancer prevention, early diagnosis, and treatment, cancer morbidity and mortality has not been decreased during last forty years. Especially, lung cancer is top-ranked in cancer-associated human death. Therefore, effective strategy is strongly required for the management of lung cancer. In the present study, we found that novel daphnane diterpenoids, yuanhualine (YL), yuanhuahine (YH) and yuanhuagine (YG) isolated from the flower of Daphne genkwa (Thymelaeaceae), exhibited potent anti-proliferative activities against human lung A549 cells with the $IC_{50}$ values of 7.0, 15.2 and 24.7 nM, respectively. Flow cytometric analysis revealed that the daphnane diterpenoids induced cell-cycle arrest in the G0/G1 as well as G2/M phase in A549 cells. The cell-cycle arrests were well correlated with the expression of checkpoint proteins including the up-regulation of cyclin-dependent kinase inhibitor p21 and p53 and down-regulation of cyclin A, cyclin B1, cyclin E, cyclin dependent kinase 4, cdc2, phosphorylation of Rb and cMyc expression. In the analysis of signal transduction molecules, the daphnane diterpenoids suppressed the activation of Akt, STAT3 and Src in human lung cancer cells. The daphnane diterpenoids also exerted the potent anti-proliferative activity against anticancer-drug resistant cancer cells including gemcitabine-resistant A549, gefitinib-, erlotinib-resistant H292 cells. Synergistic effects in the growth inhibition were also observed when yuanhualine was combined with gemcitabine, gefitinib or erlotinib in A549 cells. Taken together, these findings suggest that the novel daphnane diterpenoids might provide lead candidates for the development of therapeutic agents for human lung cancers.

• Natural Product Sciences
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• v.4 no.2
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• pp.68-71
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• 1998

Three grayanane diterpenoids (1-3) were isolated from Pieris formosa. 1 was identified as a new natural product and 2 and 3 as known grayanoside C and grayanotoxin XVIII on the basis of spectral analysis.

• Korean Journal of Plant Resources
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• v.4 no.2
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• pp.35-38
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• 1991

Two new diterpene compounds have been isolate from the roots of Eragrostis ferruginea (Thunb.) Beauv. and their structures were elucidated as isopimara-9(11), 15-0ien-l9-ol-3-one and cassa-13(14), 15-diene-3, 12-dione by various spectroscopic me-thods. We have also isolated a known diterpene diol isopimara-9(11). 15-diene-3$\beta$, 19-dio1.

• Natural Product Sciences
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• v.9 no.4
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• pp.220-222
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• 2003

Two new abietane diterpenes with rearranged skeleton; aegyptinol and aegyptinone C; have been isolated and identified for the first time from the anti-microbial petroleum ether extract of the roots of Salvia aegyptiaca L. Their chemical structures have been elucidated by interpretation of the detailed 1D-and 2D-NMR spectra, as well as other spectroscopic tools. In addition, full assignment of $^{13}C-NMR$ of aegyptinone B was also conducted for the first time.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2000.04a
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• pp.10-14
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• 2000

The cycloooxygenase enzymes catalyze the oxidative conversion of arachidonic acid into prostag1andin H$_2$Which mediates both benificial and pathological effects. The COX-1 is constitutively expressed in most tissues and in blood platelets wherease the expression of COX-2 isoform is induced in response to inflmmatory stimuli such as cyctokynes. Thus the identification of a novel COX-2 selective inhibitor should offer excellent antiinflammatory activity with minimal side effects such as gastrointestinal toxicity. Recently, a group of structurally unique and biologically active pimarane diterpenoids has been isolated from indigenous Korean medicinal plants. These new diterpenoids turned out to be potential analgesic and antiinflammatory agent due to their potent inhibitory activities of prostaglandin synthesis. We have also found that the inhibition of PGE$_2$synthesis is attributed to the potent COX inhibition by pimarane diterpenoid in arachidonic acid cascade. In conjunction with development of new analgesic and nonsteroidal antiinflammatory agent, a series of works on these diterpenoids have been extensively carried out in our laboratories. These efforts involve the structure-activity relationship of pimaradienoic acid, molecular modelings and COX inibitory activities as well as actiinflammatory effects of its structural analogues. In addition, the total syntheses of the new natural pimarane diterpenoids, their stereoisomers and other structural variants were intensively investigated.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.92-97
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• 1992

Microbial transformation of (-)kaur-l6-en-19-oic acid and (-)pimara-9(1l), 15-dien-19-oic acid from A. koreanum was investigated. Throughout the screening of the capability of metabolizing these bioactive diterpenoids, two microorganisms have chosen among various fungi and streptomycetes tested. Scale-up fermentation with Fusarium oxysporum KCTC 6051 produced two metabolites related to the precursor diterpenoids. The two metabolites were isolated by column chromatography and identified by chemical and spectroscopic methods as $2\beta$, $16\alpha$-dihydroxy kauran-19-oic acid and $16\alpha$-hydroxy kauran-19-oic acid. However any microorganisms capable to transform (-) pimara-9(11), 15-dien-19-oic acid was not screened in this condition.

• Natural Product Sciences
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• v.4 no.3
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• pp.143-147
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• 1998

Examination of the chemical constituents of the dried leaves of Isodon eriocalyx (Dunn.) Hara led to the isolation of four new diterpenoids, named maoecrystal Q-T (1-4). Their structures were elucidated as $16(R)-methoxymethyl-6{\beta},\;7{\beta}-dihydroxy-7{\alpha},20-epoxy-ent-kaur-2,3-ethenylene-1$, 15-dione(1), $1{\beta},18-diacetoxy-6{\beta},7{\beta}-dihydroxy-7{\alpha},20-epoxy-ent-kaur-16-en-15-one\;(2),\;6{\beta},\;7{\beta}-dihydroxy-15{\beta}-acetoxy-7{\alpha},20-epoxy-ent-kaur-16-en-1-one$ (3) and $7{\beta}-hydroxy-6{\beta},15{\beta}-diacetoxy-1{\alpha},11{\beta}-acetonide-7{\alpha},20-epoxy-ent-kaur-16-ene$ (4), respectively, on the basis of spectroscopic methods. Meanwhile, five known diterpeonids eriocalyxin B (5), maoecrystal B-D (6-8) and trichokaurin (9) were also obtained.

• Korean Journal of Pharmacognosy
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• v.5 no.1
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• pp.17-29
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• 1974