Cytotoxic Fusicoccane-Type Diterpenoids from <i>Streptomyces violascens</i> Isolated from <i>Ailuropoda melanoleuca</i> Feces

Six new fusicoccane-type diterpenoids (<b>2</b>–<b>7</b>) were isolated from the fermentation broth of <i>Streptomyces violascens</i>, which was isolated from <i>Ailuropoda melanoleuca</i> (giant panda) feces. The structures of these new compounds were elucidated by a detailed spectroscopic data and X-ray crystallographic analysis. Compounds <b>5</b>–<b>7</b> demonstrated cytotoxicity against five human cancer cell lines, with IC₅₀ values ranging from 3.5 ± 0.7 to 14.1 ± 0.8 μM. Cell adhesion, migration, and invasion assays showed that <b>6</b> inhibited the migration and invasion of human hepatocellular carcinoma SMMC7721 cells in a dose-dependent manner. Through further investigation, it was revealed that <b>6</b> inhibited the enzymatic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), in addition to down-regulating the expressions of MMP-2 and MMP-9 at both the protein and mRNA levels to influence the migration and invasion of cancer cells

Cytotoxic Fusicoccane-Type Diterpenoids from <i>Streptomyces violascens</i> Isolated from <i>Ailuropoda melanoleuca</i> Feces

Six new fusicoccane-type diterpenoids (<b>2</b>–<b>7</b>) were isolated from the fermentation broth of <i>Streptomyces violascens</i>, which was isolated from <i>Ailuropoda melanoleuca</i> (giant panda) feces. The structures of these new compounds were elucidated by a detailed spectroscopic data and X-ray crystallographic analysis. Compounds <b>5</b>–<b>7</b> demonstrated cytotoxicity against five human cancer cell lines, with IC₅₀ values ranging from 3.5 ± 0.7 to 14.1 ± 0.8 μM. Cell adhesion, migration, and invasion assays showed that <b>6</b> inhibited the migration and invasion of human hepatocellular carcinoma SMMC7721 cells in a dose-dependent manner. Through further investigation, it was revealed that <b>6</b> inhibited the enzymatic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), in addition to down-regulating the expressions of MMP-2 and MMP-9 at both the protein and mRNA levels to influence the migration and invasion of cancer cells