Randainins A–D, Based on Unique Diterpenoid Architectures, from <i>Callicarpa randaiensis</i>

Four new compounds, randainins A–D (<b>1</b>–<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 IC₅₀ value of 21.5 ± 2.5 μM

Iron-Catalyzed Oxidative Direct α‑C–H Bond Functionalization of Cyclic Ethers: Selective C–O Bond Formation in the Presence of a Labile Aldehyde Group

Iron catalyzed oxidative coupling of salicylaldehydes with cyclic ethers proceeded through the direct α-C–H functionalization of ethers, forming the corresponding acetals in moderate to excellent yields. This is the first example of iron catalyzed selective C–O 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 C–O 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>–<b>4</b>), callilongisins A–D, and five known compounds, ursolic acid, 3-oxoanticopalic acid, (<i>E</i>)-6β-hydroxylabda-8­(17),13-dien-15-oic acid, 5-hydroxy-3,6,7,4′-tetramethoxyflavone, and artemetin. Compounds <b>1</b>–<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 A–C (<b>1</b>–<b>3</b>), buxifobenzoate (<b>4</b>), and 7-<i>O</i>-(7′-peroxygeranyl) coumarin (<b>5</b>), together with 25 known compounds, were identified from the twigs of Atalantia buxifolia. Compounds <b>1</b>–<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 IC₅₀ value of 4.8 ± 0.7 μM. Among the acridone alkaloids, 5-hydroxy-<i>N</i>-methylseverifoline (<b>23</b>) exhibited antidengue activity (IC₅₀ = 5.3 ± 0.4 μM), and atalaphyllinine (<b>20</b>) demonstrated cytotoxicity (IC₅₀ = 6.5 ± 0.0 μM) against the human liver cancer cell line, HepG2

Bioactive Phenolic Components from the Twigs of Atalantia buxifolia

Five new compounds named buxifoximes A–C (<b>1</b>–<b>3</b>), buxifobenzoate (<b>4</b>), and 7-<i>O</i>-(7′-peroxygeranyl) coumarin (<b>5</b>), together with 25 known compounds, were identified from the twigs of Atalantia buxifolia. Compounds <b>1</b>–<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 IC₅₀ value of 4.8 ± 0.7 μM. Among the acridone alkaloids, 5-hydroxy-<i>N</i>-methylseverifoline (<b>23</b>) exhibited antidengue activity (IC₅₀ = 5.3 ± 0.4 μM), and atalaphyllinine (<b>20</b>) demonstrated cytotoxicity (IC₅₀ = 6.5 ± 0.0 μM) 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 A–F (<b>1</b>–<b>6</b>), along with 20 known compounds. Compounds <b>1</b> and <b>2</b>, mexicanolide-type limonoids, were assigned with an α,β-unsaturated δ-lactone moiety (ring D) and a CC bond between C-8 and C-30. Compounds <b>3</b>–<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>–<b>10</b> were found to show inhibitory activity in the range 3.5 to 12.5 μM. Among these, the new limonoid <b>2</b> exhibited significant antiviral activity (EC₅₀ = 7.2 ± 1.33 μM) with a selectivity index (CC₅₀/EC₅₀) 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 [5α-iodozoanthenamine (<b>1</b>) and 11β-chloro-11-deoxykuroshine A (<b>2</b>)], along with four new zoanthamines [18-<i>epi-</i>kuroshine A (<b>3</b>), 7α-hydroxykuroshine E (<b>4</b>), 5α-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. malaccensis</i> seeds has led to the isolation of four new phorbol esters (<b>1</b>–<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 IC₅₀ values of 2.7, 0.8, and 2.1 μM, 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 (IC₅₀ > 10 μM)

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>–<b>3</b>) and two new polyacetylenes (<b>4</b> and <b>5</b>), together with seven known compounds (<b>6</b>–<b>12</b>). The structures of <b>1</b>–<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 Mosher’s 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