Highly Rigid Labdane-Type Diterpenoids from a Chinese Liverwort and Light-Driven Structure Diversification

Two unprecedented labdane-type diterpenoids haplomintrins A (<b>1</b>) and B (<b>2</b>) with six rings system were isolated from a Chinese liverwort <i>Haplomitrium mnioides</i>. Light-driven reaction of homologous haplomitrenonolides C (<b>6</b>), A (<b>4</b>), and D (<b>3</b>) afforded haplomintrins A–C (<b>1</b>, <b>2</b>, and <b>7</b>), respectively, while <b>4</b> was converted to more complex congeners haplomintrins D–G (<b>8</b>–<b>11</b>) through intramolecular cyclization. Formation of <b>1</b> and <b>2</b> from compounds <b>6</b> and <b>4</b>, respectively, helps us to postulate that a photochemical reaction is involved in the biosynthetic pathway. These structure features can be used as molecular markers of <i>H. mnioides</i>, and their allelopathic effects are also preliminarily tested

Bibenzyl-Based Meroterpenoid Enantiomers from the Chinese Liverwort <i>Radula sumatrana</i>

Six new pairs of bibenzyl-based meroterpenoid enantiomers, (±)-rasumatranin A–D (<b>1</b>–<b>4</b>) and (±)-radulanin M and N (<b>5</b> and <b>6</b>), and six known compounds were isolated from the adnascent Chinese liverwort, <i>Radula sumatrana.</i> Their structures were elucidated based on spectroscopic data and chiral phase HPLC-ECD analyses. The structures of <b>1</b> and <b>7</b> were also confirmed by single-crystal X-ray diffraction analysis. Cytotoxicity tests of the isolated compounds showed that 6-hydroxy-3-methyl-8-phenylethylbenzo­[<i>b</i>]­oxepin-5-one (<b>8</b>) showed activity against the human cancer cell lines MCF-7, PC-3, and SMMC-7721, with IC₅₀ values of 3.86, 6.60, and 3.58 μM, respectively, and induced MCF-7 cell death through a mitochondria-mediated apoptosis pathway

Scapairrins A–Q, Labdane-Type Diterpenoids from the Chinese Liverwort <i>Scapania irrigua</i> and Their Cytotoxic Activity

Seventeen new labdane-type diterpenoids, scapairrins A–Q (<b>1</b>–<b>17</b>), including six pairs of diastereoisomers, and three known analogues (<b>18</b>–<b>20</b>) were isolated from the Chinese liverwort <i>Scapania irrigua</i>. The structures of <b>1</b>–<b>17</b> were determined based on a combination of the analysis of their MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Cytotoxicity testing showed that compounds <b>7</b>–<b>10</b> exhibited inhibitory activities against a small panel of human cancer cell lines

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Ophiosphaerellins A–I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

Ophiosphaerellins A–I (<b>1</b>–<b>9</b>), the first example of bicyclo[4.1.0]­heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A–B (<b>10</b>–<b>11</b>) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects

Marsupellins A–F, <i>ent</i>-Longipinane-Type Sesquiterpenoids from the Chinese Liverwort <i>Marsupella alpine</i> with Acetylcholinesterase Inhibitory Activity

Acetylcholinesterase (AChE) inhibitory activity-guided fractionation of the Chinese liverwort <i>Marsupella alpine</i> afforded six new [marsupellins A–F (<b>1</b>–<b>6</b>)] and three known (<b>7</b>–<b>9</b>) <i>ent</i>-longipinane-type sesquiterpenoids. The structures were determined from MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds <b>1</b>–<b>9</b> exhibited moderate to weak AChE inhibitory activity

Ophiosphaerellins A–I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

Ophiosphaerellins A–I (<b>1</b>–<b>9</b>), the first example of bicyclo[4.1.0]­heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A–B (<b>10</b>–<b>11</b>) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects