12 research outputs found
Randainins AāD, Based on Unique Diterpenoid Architectures, from <i>Callicarpa randaiensis</i>
Four new compounds, randainins AāD
(<b>1</b>ā<b>4</b>), were isolated from the leaves
and twigs of <i>Callicarpa randaiensis</i>, which is an
endemic species in Taiwan. Compounds <b>1</b> and <b>2</b> are diterpenoids with an unusual <i>trans</i>-7/5 ring
system, whereas compounds <b>3</b> and <b>4</b> are diterpenoids
possessing a <i>trans</i>-5/7 ring scaffold. The structures
of the new compounds were established based on NMR and MS data analyses.
Anti-inflammatory activities and cytotoxicity were tested and evaluated
for these compounds. Compound <b>4</b> exhibited moderate inhibition
of superoxide-anion generation with an IC<sub>50</sub> value of 21.5
Ā± 2.5 Ī¼M
Iron-Catalyzed Oxidative Direct Ī±āCāH Bond Functionalization of Cyclic Ethers: Selective CāO Bond Formation in the Presence of a Labile Aldehyde Group
Iron
catalyzed oxidative coupling of salicylaldehydes with cyclic
ethers proceeded through the direct Ī±-CāH functionalization
of ethers, forming the corresponding acetals in moderate to excellent
yields. This is the first example of iron catalyzed selective CāO
bond formation in the presence of a sensitive aldehyde moiety
Copper-Catalyzed Oxidative Coupling of Formamides with Salicylaldehydes: Synthesis of Carbamates in the Presence of a Sensitive Aldehyde Group
A diverse library of novel carbamates
was synthesized utilizing
copper-catalyzed oxidative CāO coupling of formamides and salicylaldehydes.
Sensitive aldehyde groups remained intact in the presence of an oxidant
and a transition-metal salt. Salicylaldehydes bearing electron-donating,
electron-withdrawing, and halogen groups as well as 1-hydroxy-2-naphthaldehydes
provided the desired carbamates in good to excellent yields
Bioactive Diterpenes from <i>Callicarpa longissima</i>
Investigation of the leaves and twigs of <i>Callicarpa
longissima</i> resulted in the isolation of four new compounds
(<b>1</b>ā<b>4</b>), callilongisins AāD,
and five known compounds, ursolic acid, 3-oxoanticopalic acid, (<i>E</i>)-6Ī²-hydroxylabda-8Ā(17),13-dien-15-oic acid, 5-hydroxy-3,6,7,4ā²-tetramethoxyflavone,
and artemetin. Compounds <b>1</b>ā<b>3</b> are
3,4-<i>seco</i>-abietane-type diterpenoids, and compound <b>4</b> is an analogue of a labdenoic-type diterpene. The structure
of compound <b>1</b> was confirmed by X-ray crystallographic
analysis. Cytotoxicity against a human prostate cancer cell line (PC3)
and anti-inflammatory activities of the isolated compounds were evaluated
Bioactive Phenolic Components from the Twigs of Atalantia buxifolia
Five new compounds named buxifoximes
AāC (<b>1</b>ā<b>3</b>), buxifobenzoate
(<b>4</b>), and 7-<i>O</i>-(7ā²-peroxygeranyl)
coumarin (<b>5</b>), together
with 25 known compounds, were identified from the twigs of Atalantia buxifolia. Compounds <b>1</b>ā<b>3</b> are unique secondary metabolites with the aldoxime functionality.
The structures of the isolates were determined on the basis of spectroscopic
data analyses, and the structure of <b>1</b> was confirmed by
an X-ray single-crystallographic analysis. With respect to bioactivity,
antidengue virus, anti-inflammatory, and cytotoxic activities of all
purified compounds were tested and evaluated. Compound <b>1</b> showed a significant anti-inflammatory effect by inhibiting superoxide
anion generation with an IC<sub>50</sub> value of 4.8 Ā± 0.7 Ī¼M.
Among the acridone alkaloids, 5-hydroxy-<i>N</i>-methylseverifoline
(<b>23</b>) exhibited antidengue activity (IC<sub>50</sub> =
5.3 Ā± 0.4 Ī¼M), and atalaphyllinine (<b>20</b>) demonstrated
cytotoxicity (IC<sub>50</sub> = 6.5 Ā± 0.0 Ī¼M) against the
human liver cancer cell line, HepG2
Bioactive Phenolic Components from the Twigs of Atalantia buxifolia
Five new compounds named buxifoximes
AāC (<b>1</b>ā<b>3</b>), buxifobenzoate
(<b>4</b>), and 7-<i>O</i>-(7ā²-peroxygeranyl)
coumarin (<b>5</b>), together
with 25 known compounds, were identified from the twigs of Atalantia buxifolia. Compounds <b>1</b>ā<b>3</b> are unique secondary metabolites with the aldoxime functionality.
The structures of the isolates were determined on the basis of spectroscopic
data analyses, and the structure of <b>1</b> was confirmed by
an X-ray single-crystallographic analysis. With respect to bioactivity,
antidengue virus, anti-inflammatory, and cytotoxic activities of all
purified compounds were tested and evaluated. Compound <b>1</b> showed a significant anti-inflammatory effect by inhibiting superoxide
anion generation with an IC<sub>50</sub> value of 4.8 Ā± 0.7 Ī¼M.
Among the acridone alkaloids, 5-hydroxy-<i>N</i>-methylseverifoline
(<b>23</b>) exhibited antidengue activity (IC<sub>50</sub> =
5.3 Ā± 0.4 Ī¼M), and atalaphyllinine (<b>20</b>) demonstrated
cytotoxicity (IC<sub>50</sub> = 6.5 Ā± 0.0 Ī¼M) against the
human liver cancer cell line, HepG2
Limonoids from the Seeds of <i>Swietenia macrophylla</i> with Inhibitory Activity against Dengue Virus 2
Fractionation of an ethanol-soluble
extract of the seeds of <i>Swietenia macrophylla</i> yielded
six new limonoids, swielimonoids
AāF (<b>1</b>ā<b>6</b>), along with 20 known
compounds. Compounds <b>1</b> and <b>2</b>, mexicanolide-type
limonoids, were assigned with an Ī±,Ī²-unsaturated Ī“-lactone
moiety (ring D) and a Cī»C bond between C-8 and C-30. Compounds <b>3</b>ā<b>6</b> could be categorized as highly oxygenated
phragmalin-type limonoids. The structures of these new compounds were
elucidated through the interpretation of spectroscopic data. The antidengue
virus 2 activities of the isolated components from <i>S. macrophylla</i> were investigated, and of 12 compounds subjected to bioassay, compounds <b>2</b> and <b>7</b>ā<b>10</b> were found to
show inhibitory activity in the range 3.5 to 12.5 Ī¼M. Among
these, the new limonoid <b>2</b> exhibited significant antiviral
activity (EC<sub>50</sub> = 7.2 Ā± 1.33 Ī¼M) with a selectivity
index (CC<sub>50</sub>/EC<sub>50</sub>) value of >27.7
Zoanthamine-Type Alkaloids from the Zoanthid <i>Zoanthus kuroshio</i> Collected in Taiwan and Their Effects on Inflammation
<i>Zoanthus kuroshio</i> is a colorful zoanthid with a fluorescent pink oral disc and brown
tentacles, which dominates certain parts of the Taiwanese and Japanese
coasts. This sea anemone is a rich source of biologically active alkaloids.
In the current investigation, two novel halogenated zoanthamines [5Ī±-iodozoanthenamine
(<b>1</b>) and 11Ī²-chloro-11-deoxykuroshine A (<b>2</b>)], along with four new zoanthamines [18-<i>epi-</i>kuroshine
A (<b>3</b>), 7Ī±-hydroxykuroshine E (<b>4</b>),
5Ī±-methoxykuroshine E (<b>5</b>), and 18-<i>epi</i>-kuroshine E (<b>6</b>)], and six known compounds were isolated
from <i>Z. kuroshio</i>. Compounds <b>1</b> and <b>2</b> are the first examples of halogenated zoanthamine-type alkaloids
isolated from nature. Compounds <b>3</b> and <b>6</b> are
the first zoanthamine stereoisomers with a <i>cis</i>-junction
of the A/B rings. All isolated compounds were evaluated for their
anti-inflammatory activities by measuring their effects on superoxide
anion generation and elastase release by human neutrophils in response
to fMLP
Inflammation Modulatory Phorbol Esters from the Seeds of <i>Aquilaria malaccensis</i>
The tree <i>Aquilaria malaccensis</i> is a valuable source
of agarwood, which is used in herbal medicinal preparations. Phytochemical
research on <i>A.Ā malaccensis</i> seeds has led to
the isolation of four new phorbol esters (<b>1</b>ā<b>4</b>), two known phorbol esters (<b>5</b>, isolated from
Nature for the first time, and <b>6</b>), and two known glycerides
(<b>7</b> and <b>8</b>). The structures of these isolates
were elucidated by means of spectroscopic data interpretation. The
inflammation-modulatory activities of the isolates on elastase release
and superoxide anion generation in human neutrophils were evaluated.
Interestingly, phorbol esters <b>1</b>, <b>5</b>, and <b>6</b> showed potent inhibitory activity on elastase release in
human neutrophils, with IC<sub>50</sub> values of 2.7, 0.8, and 2.1
Ī¼M, respectively. All isolated phorbol esters exerted enhancing
activity on superoxide anion generation. The results indicated that
phorbol esters may play a bilateral modulatory role in the processes
of inflammation. In addition, the compounds were evaluated for their
cytotoxic properties against HepG2 (hepatoma), MDA-MB-231 (breast),
and A549 (lung) cancer cells, but all compounds were inactive for
all cell lines used (IC<sub>50</sub> > 10 Ī¼M)
Bioactive Constituents of <i>Cirsium japonicum</i> var. <i>australe</i>
<i>Cirsium japonicum</i> var. <i>australe</i>, used as a folk medicine in Taiwan,
has been employed traditionally
in the treatment of diabetes and inflammatory symptoms. Bioactivity-guided
fractionation of its ethanolic extract, utilizing centrifugal partition
chromatography monitored by DPPH-TLC analysis, led to the isolation
of three new acetylenic phenylacrylic acid esters (<b>1</b>ā<b>3</b>) and two new polyacetylenes (<b>4</b> and <b>5</b>), together with seven known compounds (<b>6</b>ā<b>12</b>). The structures of <b>1</b>ā<b>5</b> were elucidated by spectroscopic methods including 1D and 2D NMR
techniques. The absolute configurations of <b>4</b> and <b>7</b> were determined utilizing Mosherās method and ECD/CD
experiments. The DPPH scavenging activity of the constituents isolated
from the <i>C. japonicum</i> var. <i>australe</i> ethanolic extract was evaluated. The potential antidiabetic activity
of some of the isolates was evaluated using in vitro cellular glucose
uptake and oil red staining assays