<i>Monascus</i> fermented rice, also known as red yeast rice, exhibits a broad spectr... more <i>Monascus</i> fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological activities due to its chemical constituents, such as monacolins and azaphilone pigments. Here, we cultured <i>Monascus kaoliang</i> KB9 in a liquid malt medium instead of on rice as a carbon source. Eleven known compounds (<b>1</b>–<b>11</b>) containing azaphilones and their early intermediate were isolated and identified. However, this was the first time that angular tricyclic azaphilones, monasfluols A (<b>4</b>) and B (<b>7</b>), acetyl-monasfluol A (<b>5</b>) and monasfluore A (<b>6</b>), were isolated from this species. Interestingly, all isolated tricyclic azaphilones existed exclusively in enol form in CD<sub>3</sub>OD, as evidenced by NMR spectroscopy. The absolute configuration of compounds <b>4</b>–<b>7</b> was also first experimentally identified based on ECD spectroscopy combined with conformational analyses using computational techniques. The assigned stereochemistry of <i>Monascus</i> azaphilones in this work provides essential structural information that will benefit future biological and pharmaceutical investigations.
Monascus fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological ac... more Monascus fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological activities due to its chemical constituents, such as monacolins and azaphilone pigments. Here, we cultured Monascus kaoliang KB9 in a liquid malt medium instead of on rice as a carbon source. Eleven known compounds (1-11) containing azaphilones and their early intermediate were isolated and identified. However, this was the first time that angular tricyclic azaphilones, monasfluols A (4) and B (7), acetyl-monasfluol A (5) and monasfluore A (6), were isolated from this species. Interestingly, all isolated tricyclic azaphilones existed exclusively in enol form in CD3OD, as evidenced by NMR spectroscopy. The absolute configuration of compounds 4-7 was also first experimentally identified based on ECD spectroscopy combined with conformational analyses using computational techniques. The assigned stereochemistry of Monascus azaphilones in this work provides essential structural information that...
<i>Monascus</i> fermented rice, also known as red yeast rice, exhibits a broad spectr... more <i>Monascus</i> fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological activities due to its chemical constituents, such as monacolins and azaphilone pigments. Here, we cultured <i>Monascus kaoliang</i> KB9 in a liquid malt medium instead of on rice as a carbon source. Eleven known compounds (<b>1</b>–<b>11</b>) containing azaphilones and their early intermediate were isolated and identified. However, this was the first time that angular tricyclic azaphilones, monasfluols A (<b>4</b>) and B (<b>7</b>), acetyl-monasfluol A (<b>5</b>) and monasfluore A (<b>6</b>), were isolated from this species. Interestingly, all isolated tricyclic azaphilones existed exclusively in enol form in CD<sub>3</sub>OD, as evidenced by NMR spectroscopy. The absolute configuration of compounds <b>4</b>–<b>7</b> was also first experimentally identified based on ECD spectroscopy combined with conformational analyses using computational techniques. The assigned stereochemistry of <i>Monascus</i> azaphilones in this work provides essential structural information that will benefit future biological and pharmaceutical investigations.
Monascus fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological ac... more Monascus fermented rice, also known as red yeast rice, exhibits a broad spectrum of biological activities due to its chemical constituents, such as monacolins and azaphilone pigments. Here, we cultured Monascus kaoliang KB9 in a liquid malt medium instead of on rice as a carbon source. Eleven known compounds (1-11) containing azaphilones and their early intermediate were isolated and identified. However, this was the first time that angular tricyclic azaphilones, monasfluols A (4) and B (7), acetyl-monasfluol A (5) and monasfluore A (6), were isolated from this species. Interestingly, all isolated tricyclic azaphilones existed exclusively in enol form in CD3OD, as evidenced by NMR spectroscopy. The absolute configuration of compounds 4-7 was also first experimentally identified based on ECD spectroscopy combined with conformational analyses using computational techniques. The assigned stereochemistry of Monascus azaphilones in this work provides essential structural information that...
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