7 research outputs found
Myrifabine, the First Dimeric <i>Myrioneuron</i> Alkaloid from <i>Myrioneuron faberi</i>
One <i>Myrioneuron</i> alkaloid, myrifabine (<b>1</b>), the first
example of a dimer with 12 chiral centers embraced in a decacyclic
novel skeleton, was isolated from <i>Myrioneuron
faberi</i>. Its structure was elucidated by spectroscopic
data and single-crystal X-ray diffraction. The antimicrobial and cytotoxic
activities of <b>1</b> were evaluated in vitro
Myrifabine, the First Dimeric <i>Myrioneuron</i> Alkaloid from <i>Myrioneuron faberi</i>
One <i>Myrioneuron</i> alkaloid, myrifabine (<b>1</b>), the first
example of a dimer with 12 chiral centers embraced in a decacyclic
novel skeleton, was isolated from <i>Myrioneuron
faberi</i>. Its structure was elucidated by spectroscopic
data and single-crystal X-ray diffraction. The antimicrobial and cytotoxic
activities of <b>1</b> were evaluated in vitro
Two Unusual Polycyclic Polyprenylated Acylphloroglucinols, Including a Pair of Enantiomers from <i>Garcinia multiflora</i>
Two
polycyclic polyprenylated acylphloroglucinols, garcimulins
A and B ((±)-<b>1</b> and <b>2</b>), including a
pair of enantiomers with the unique caged tetracycloÂ[5.4.1.1<sup>1,5</sup>.0<sup>9,13</sup>]Âtridecane skeleton were isolated from <i>Garcinia
multiflora</i>. Their structures and absolute configurations
were determined by extensive analysis of spectroscopic data and electronic
circular dichroism (ECD) calculations. Compounds <b>1</b> and <b>2</b> exhibited cytotoxic activities against five human cancer
cell lines in vitro (IC<sub>50</sub> 3.42–13.23 μM).
The acidification of lysosomes in HeLa cell was obviously affected
by compound <b>2</b>
Aphanamixoid A, a Potent Defensive Limonoid, with a New Carbon Skeleton from <i>Aphanamixis polystachya</i>
Aphanamixoid A (<b>1</b>), a limonoid with a new carbon skeleton, along with its biogenetically related limonoid aphanamixoid B (<b>2</b>), was isolated from the leaves and twigs of <i>Aphanamixis polystachya</i>. Their structures with the absolute stereochemistry were determined by spectroscopic analysis, X-ray crystallography and computational methods. The significant antifeedant activity of <b>1</b> against the generalist plant-feeding insect <i>Helicoverpa armigera</i> (EC<sub>50</sub> = 0.015 μmol/cm<sup>2</sup>) suggested it may be a potent defensive component of <i>A. polystachya.</i
Alkaloids with Different Carbon Units from <i>Myrioneuron faberi</i>
Three new <i>Myrioneuron</i> alkaloids, myrifamines A–C
(<b>1</b>–<b>3</b>), with unique skeletons were
isolated from <i>Myrioneuron faberi.</i> The absolute configuration
of <b>1</b> was confirmed by single-crystal X-ray diffraction
analysis, and the stereochemistry of the other two alkaloids was determined
using a combination of ROESY experiments and calculated and experimental
electronic circular dichroism spectra. Myrifamine C (<b>3</b>) is the first example of a symmetric dimer among the <i>Myrioneuron</i> alkaloids. Known alkaloids myrionamide (<b>4</b>) and schoberine
(<b>5</b>) were also isolated, and experimental NMR and X-ray
diffraction data suggest their structural revision. Compound <b>2</b> showed significant inhibitory activity toward the hepatitis
C virus in vitro, with a therapeutic index (CC<sub>50</sub>/EC<sub>50</sub>) greater than 108.7
Trigohowilols A–G, Degraded Diterpenoids from the Stems of <i>Trigonostemon howii</i>
Two new degraded diterpenoids, trigohowilols A (<b>1</b>)
and B (<b>2</b>), four new heterodimers, trigohowilols C–F
(<b>3</b>–<b>6</b>), one new homodimer, trigohowilol
G (<b>7</b>), and three known degraded diterpenoids (<b>8</b>–<b>10</b>) were isolated from the methanol extract
of the stems of <i>Trigonostemon howii</i>. Compounds <b>1</b>–<b>7</b> were evaluated for their cytotoxic
activity against five human tumor cell lines by an MTT assay, and
trigohowilols E (<b>5</b>) and F (<b>6</b>) exhibited
inhibitory activity with IC<sub>50</sub> values ranging from 2.33
to 12.57 μM. Moreover, compounds <b>1</b>–<b>6</b> showed weak antimicrobial activities (MIC values: 6.25–25
μg/mL) against <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, MRSA 92<sup>#</sup>, and MRSA 98<sup>#</sup> using a 2-fold dilution method
Peganumine A, a β‑Carboline Dimer with a New Octacyclic Scaffold from <i>Peganum harmala</i>
Peganumine A (<b>1</b>), a
new dimeric β-carboline
alkaloid characterized by a unique 3,9-diazaÂtetraÂcycloÂ[6.5.2.0<sup>1,9</sup>.0<sup>3,8</sup>]Âpentadec-2-one scaffold, was isolated
from the seeds of <i>Peganum harmala</i>. The structure
including the absolute configuration was determined by spectroscopic
data, X-ray crystallography, ECD calculation, and CD exciton chirality
approaches. Compound <b>1</b> showed moderate cytotoxic activity
against MCF-7, PC-3, and HepG2 cells and selective effects on HL-60
cells with an IC<sub>50</sub> value of 5.8 μM