Chemical Constituents of Propolis from Vietnamese <i>Trigona minor</i> and Their Antiausterity Activity against the PANC‑1 Human Pancreatic Cancer Cell Line

The ethanol extract of propolis from the Vietnamese stingless bee <i>Trigona minor</i> possessed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells in nutrient-deprived medium, with a PC₅₀ value of 14.0 μg/mL. Chemical investigation of this extract led to the isolation of 15 cycloartane-type triterpenoids, including five new compounds (<b>1</b>–<b>5</b>), and a lanostane-type triterpenoid. The structures of the new compounds were elucidated on the basis of NMR spectroscopic analysis. Among the isolated compounds, 23-hydroxyisomangiferolic acid B (<b>5</b>) and 27-hydroxyisomangiferolic acid (<b>13</b>) exhibited the most potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 4.3 and 3.7 μM, respectively

A new bischromanone from the stems of <i>Semecarpus caudata</i>

<p>From an CHCl₃-soluble fraction of the stems of <i>Semecarpus caudata</i>, one new bischromanone named semecarpanone (<b>1</b>), together with 5 known flavonoids (<b>2</b>–<b>6</b>) were isolated. Their structures were elucidated based on interpretation of spectroscopic data. The stereo-configuration of <b>1</b> was identified based on the calculated and experimental coupling constants. Compounds <b>4</b>–<b>6</b> showed potent tyrosinase inhibitory activity with the IC₅₀ values ranging from 15.0 to 76.3 μM.</p

Artocarmins G–M, Prenylated 4‑Chromenones from the Stems of <i>Artocarpus rigida</i> and Their Tyrosinase Inhibitory Activities

Phytochemical analysis of an EtOAc extract of the stems of <i>Artocarpus rigida</i> led to the identification of seven new prenylated 4-chromenones, artocarmins G–M (<b>1</b>–<b>7</b>), and nine known compounds (<b>8</b>–<b>17</b>). Their structures were identified based on physical data analysis. In the tyrosinase inhibitory activity test, norartocarpetin (<b>8</b>) displayed the strongest effect, with an IC₅₀ value of 0.023 μM

Lignans from the Roots of <i>Taxus wallichiana</i> and Their α‑Glucosidase Inhibitory Activities

From an EtOAc-soluble extract of the roots of <i>Taxus wallichiana</i>, six new (<b>1</b>–<b>6</b>) and 11 known lignans were isolated. The structures of the new compounds were elucidated based on interpretation of spectroscopic data. (+)-7′-<i>epi</i>-Tsugacetal (<b>1</b>) is a rare aryltetralin-type lignan having a <i>cis</i>-orientation of H-7′ and H-8′. Compounds <b>3</b>–<b>6</b> were identified as the first naturally occurring tetrahydrofuranoid lignans having a <i>cis</i>-orientation of H-7 and H-8. All tested compounds were found to possess α-glucosidase inhibitory activity, with formosanol (<b>9</b>) showing the most potent effect with an IC₅₀ value of 35.3 μM