Pallambins A and B, Unprecedented Hexacyclic 19-<i>nor</i>-Secolabdane Diterpenoids from the Chinese Liverwort <i>Pallavicinia ambigua</i>

Pallambins A (<b>1</b>) and B (<b>2</b>), two novel 19-<i>nor</i>-7,8-secolabdane diterpenoids with unprecedented tetracyclo[4.4.0^3,5.0^2,8]decane skeletons, along with a pair of structurally related isomers, pallambins C (<b>3</b>) and D (<b>4</b>), were isolated from the Chinese liverwort <i>Pallavicinia ambigua</i>. Their structures with absolute configurations were determined by means of NMR, X-ray diffraction, and CD analyses. Their preliminary cytotoxicity to human cancer cells was also tested

Pallambins A and B, Unprecedented Hexacyclic 19-<i>nor</i>-Secolabdane Diterpenoids from the Chinese Liverwort <i>Pallavicinia ambigua</i>

Pallambins A (<b>1</b>) and B (<b>2</b>), two novel 19-<i>nor</i>-7,8-secolabdane diterpenoids with unprecedented tetracyclo[4.4.0^3,5.0^2,8]decane skeletons, along with a pair of structurally related isomers, pallambins C (<b>3</b>) and D (<b>4</b>), were isolated from the Chinese liverwort <i>Pallavicinia ambigua</i>. Their structures with absolute configurations were determined by means of NMR, X-ray diffraction, and CD analyses. Their preliminary cytotoxicity to human cancer cells was also tested

Cembrane-Type Diterpenoids from the Chinese Liverworts <i>Chandonanthus hirtellus</i> and <i>C. birmensis</i>

Six new cembrane-type diterpenoids (<b>1</b>–<b>6</b>) were isolated from two species of <i>Chandonanthus</i>: Chandonanones A, B, and D–F (<b>1</b>, <b>2</b>, and <b>4</b>–<b>6</b>) were isolated from <i>C. hirtellus</i>, and chandonanones B, C, E, and F (<b>2</b>, <b>3</b>, <b>5</b>, and <b>6</b>) from <i>C. birmensis</i>. Five known diterpenoids, (8<i>E</i>)-4α-acetoxy-12α,13α-epoxycembra-1­(15),8-diene (<b>7</b>), isochandonanthone (<b>8</b>), chandonanthone (<b>9</b>), anadensin (<b>10</b>), and 2,10,14-triacetoxy-7,8,18,19-diepoxydolabell-3­(<i>E</i>)-ene (<b>11</b>), were also obtained. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). The absolute configurations of compounds <b>1</b> and <b>2</b> were unequivocally confirmed using single-crystal X-ray diffraction analysis with Cu Kα radiation. Cytotoxicity tests of the isolated diterpenoids against seven cancer cell lines (DU145, PC3, A549, PC12, NCI-H292, NCI-H1299, and A172) revealed that some of the diterpenoids had weak activity

Cembrane-Type Diterpenoids from the Chinese Liverworts <i>Chandonanthus hirtellus</i> and <i>C. birmensis</i>

Six new cembrane-type diterpenoids (<b>1</b>–<b>6</b>) were isolated from two species of <i>Chandonanthus</i>: Chandonanones A, B, and D–F (<b>1</b>, <b>2</b>, and <b>4</b>–<b>6</b>) were isolated from <i>C. hirtellus</i>, and chandonanones B, C, E, and F (<b>2</b>, <b>3</b>, <b>5</b>, and <b>6</b>) from <i>C. birmensis</i>. Five known diterpenoids, (8<i>E</i>)-4α-acetoxy-12α,13α-epoxycembra-1­(15),8-diene (<b>7</b>), isochandonanthone (<b>8</b>), chandonanthone (<b>9</b>), anadensin (<b>10</b>), and 2,10,14-triacetoxy-7,8,18,19-diepoxydolabell-3­(<i>E</i>)-ene (<b>11</b>), were also obtained. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). The absolute configurations of compounds <b>1</b> and <b>2</b> were unequivocally confirmed using single-crystal X-ray diffraction analysis with Cu Kα radiation. Cytotoxicity tests of the isolated diterpenoids against seven cancer cell lines (DU145, PC3, A549, PC12, NCI-H292, NCI-H1299, and A172) revealed that some of the diterpenoids had weak activity

Cembrane-Type Diterpenoids from the Chinese Liverworts <i>Chandonanthus hirtellus</i> and <i>C. birmensis</i>

Six new cembrane-type diterpenoids (<b>1</b>–<b>6</b>) were isolated from two species of <i>Chandonanthus</i>: Chandonanones A, B, and D–F (<b>1</b>, <b>2</b>, and <b>4</b>–<b>6</b>) were isolated from <i>C. hirtellus</i>, and chandonanones B, C, E, and F (<b>2</b>, <b>3</b>, <b>5</b>, and <b>6</b>) from <i>C. birmensis</i>. Five known diterpenoids, (8<i>E</i>)-4α-acetoxy-12α,13α-epoxycembra-1­(15),8-diene (<b>7</b>), isochandonanthone (<b>8</b>), chandonanthone (<b>9</b>), anadensin (<b>10</b>), and 2,10,14-triacetoxy-7,8,18,19-diepoxydolabell-3­(<i>E</i>)-ene (<b>11</b>), were also obtained. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). The absolute configurations of compounds <b>1</b> and <b>2</b> were unequivocally confirmed using single-crystal X-ray diffraction analysis with Cu Kα radiation. Cytotoxicity tests of the isolated diterpenoids against seven cancer cell lines (DU145, PC3, A549, PC12, NCI-H292, NCI-H1299, and A172) revealed that some of the diterpenoids had weak activity

Diterpenoids from the Chinese Liverwort Heteroscyphus tener and Their Antiproliferative Effects

Four new <i>ent</i>-labdane diterpenoids, heteroscyphins A–D (<b>1</b>–<b>4</b>), and four known diterpenoids (<b>5</b>–<b>8</b>) were isolated from the Chinese liverwort Heteroscyphus tener (Steph.) Schiffn. The absolute configuration of compound <b>1</b> was defined by single-crystal X-ray diffraction using Cu Kα radiation. Cytotoxicity tests revealed that compounds <b>3</b> and <b>5</b> exhibited modest activity against seven cancer cell lines. Compound <b>5</b> showed inhibitory effects on prostate cancer (PCa) cell proliferation but with less inhibition on non-neoplastic prostate epithelial cells. Compound <b>5</b> markedly caused cell growth arrest at the G0/G1 phase and induced cellular apoptosis through ROS-mediated DNA damage in PCa cells

Two new cadinane-type sesquiterpenes from the Chinese liverwort <i>Frullania serrata</i>

<div><p>Two new cadinane-type sesquiterpenes, frullanic acid (<b>1</b>) and frullanic acid methyl ester (<b>2</b>), together with four known bibenzyls, brittonin B (<b>3</b>), 3,3′-dimethoxy-4,5-methylenedioxybibenzyl (<b>4</b>), 3,4,5,3′,4′-penlamethoxybibenzyl (<b>5</b>) and ( ± )-3-(4′-methoxybenzyl)-5,6-dimethoxyphtbalide (<b>6</b>), were isolated from the Chinese liverwort <i>Frullania serrata</i>. The structures of the new metabolites were elucidated by analysing the spectroscopic data (1D NMR, 2D NMR, HR-ESI-MS and IR). The absolute configurations of compounds <b>1</b> and <b>2</b> were determined by comparing the experimental and calculated electronic circular dichroism spectra predicted by using time-dependent density functional theory as well as the CD exciton chirality method.</p></div

Notolutesins A–J, Dolabrane-Type Diterpenoids from the Chinese Liverwort <i>Notoscyphus lutescens</i>

Ten new dolabrane-type diterpenoids, notolutesins A–J (<b>1</b>–<b>10</b>), were isolated from the Chinese liverwort <i>Notoscyphus lutescens</i>, along with four known compounds. The structures of the new compounds were established on the basis of extensive spectroscopic data, and that of <b>1</b> was confirmed by single-crystal X-ray crystallography. The absolute configuration of <b>1</b> was determined by comparing its experimental and calculated electronic circular dichroism spectra. All of the isolates were evaluated for their cytotoxicity against a small panel of human cancer cell lines, and compound <b>1</b> exhibited an IC₅₀ value of 6.2 μM against the PC3 human prostate cancer cell line

Notolutesins A–J, Dolabrane-Type Diterpenoids from the Chinese Liverwort <i>Notoscyphus lutescens</i>

Ten new dolabrane-type diterpenoids, notolutesins A–J (<b>1</b>–<b>10</b>), were isolated from the Chinese liverwort <i>Notoscyphus lutescens</i>, along with four known compounds. The structures of the new compounds were established on the basis of extensive spectroscopic data, and that of <b>1</b> was confirmed by single-crystal X-ray crystallography. The absolute configuration of <b>1</b> was determined by comparing its experimental and calculated electronic circular dichroism spectra. All of the isolates were evaluated for their cytotoxicity against a small panel of human cancer cell lines, and compound <b>1</b> exhibited an IC₅₀ value of 6.2 μM against the PC3 human prostate cancer cell line