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 tetracyclo­[5.4.1.1^1,5.0^9,13]­tridecane 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 (IC₅₀ 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> (EC₅₀ = 0.015 μmol/cm²) 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 (CC₅₀/EC₅₀) 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 IC₅₀ 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^#, and MRSA 98^# 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-diaza­tetra­cyclo­[6.5.2.0^1,9.0^3,8]­pentadec-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 IC₅₀ value of 5.8 μM