A novel pyrrole alkaloid from the fruit peels of <i>Strychnos nux</i>-<i>blanda</i>

<p>A novel pyrrole alkaloid, strychnuxin (<b>1</b>), along with five known compounds (<b>2</b>–<b>6</b>) was isolated from the fruit peels of <i>Strychnos nux</i>-<i>blanda</i>. The structures of all the isolated compounds (<b>1</b>–<b>6</b>) were fully characterised using spectroscopic data, as well as comparison with the previous literature data. Moreover, all isolated compounds were assessed for their <i>α</i>-glucosidase and acetylcholinesterase inhibitory activities.</p

Caloinophyllin A, a new chromanone derivative from <i>Calophyllum inophyllum</i> roots

<p>A new chromanone derivative, namely caloinophyllin A (<b>1</b>), along with eight known compounds (<b>2</b>–<b>9</b>), nobiletin (<b>2</b>), pentamethylquercetin (<b>3</b>), 3,5,7,4′-tetramethoxyflavone (<b>4</b>), 5,7,4′-trimethoxyflavone (<b>5</b>), 1,5-dihydroxyxanthone (<b>6</b>), 1,8-dimethoxy-2-hydroxyxanthone (<b>7</b>), 1,6-dihydroxy-7-methoxyxanthone (<b>8</b>) and 4-methoxycaffeic acid (<b>9</b>) were isolated from the roots of <i>Calophyllum inophyllum</i>. The structures of all the isolated compounds (<b>1</b>–<b>9</b>) were fully characterised using spectroscopic data, as well as comparison with the previous literature data. In addition, the quantum chemical calculation has been used to confirm the conformation of <b>1</b>. Moreover, all isolated compounds were assessed for their <i>in vitro</i> cytotoxicity against five human cancer cell lines.</p

Two new dimethylpyranoflavanones from the roots of <i>Melodorum fruticosum</i>

Two previously unreported dimethylpyranoflavanones, pyronomelodorones A and B (1 and 2), along with five known compounds, 7-O-methyldihydrowogonin (3), 5,6,7-trimethoxyflavanone (4), 5,6-dihydroxy-7-methoxy-dihydroflavone (5), 5,7,8-trimethoxydihydroflavone (6), and pinostrobin (7), were isolated from the roots of Melodorum fruticosum. The structures of all isolates were fully characterized using spectroscopic data and comparison with the previous literature. All isolates were evaluated for their in vitro α-glucosidase inhibition and their cytotoxicity against KB, HepG2, and MCF7 cell lines. Among the isolates, compound 1 exhibited the most inhibitory activity against α-glucosidase and was superior to the positive control with an IC50 value of 1.32 μM. Compounds 1 and 2 showed weak cytotoxicity against the three human cancer cell lines, with IC50 values in the range of 53.3–79.0 μM.</p

Parmoferone A, a new depsidone from the lichen <i>Parmotrema cristiferum</i>

A new depsidone, parmoferone A (1), together with three known compounds, parmosidone K (2), albifolione (3), and 4-chloroorcinol (4) were isolated from the lichen Parmotrema cristiferum (Taylor) Hale (Parmeliaceae). The structures of isolated compounds were identified from its spectroscopic data and by comparison with the literature. Compounds 1-4 were evaluated for alpha-glucosidase inhibition. Compound 1 was determined to be a potent non-competitive inhibitor against alpha-glucosidase with an IC50 value of 18.1 μM.</p