Tyrosinase Inhibitors from the Wood of <i>Artocarpus heterophyllus</i>

From the methanolic-soluble extract of the wood of <i>Artocarpus heterophyllus</i>, four new flavones, artocarmins A–D (<b>1</b>–<b>4</b>), and three new chalcones, artocarmitins A–C (<b>5</b>–<b>7</b>), have been isolated together with 13 known compounds. Their structures were determined on the basis of the spectroscopic data. Compounds <b>1</b>–<b>4</b>, <b>6</b>, <b>7</b>, <b>9</b>–<b>16</b>, and <b>20</b> displayed significant tyrosinase inhibitory activity. The most active compound, morachalcone A (<b>12</b>) (IC₅₀, 0.013 μM), was 3000 times more active as a tyrosinase inhibitor than a positive control, kojic acid (IC₅₀, 44.6 μM)

α‑Glucosidase Inhibitory and Cytotoxic Taxane Diterpenoids from the Stem Bark of <i>Taxus wallichiana</i>

From a CH₂Cl₂ extract of the bark of <i>Taxus wallichiana</i>, six new taxoids, wallitaxanes A–F (<b>1</b>–<b>6</b>), were isolated, together with 29 known compounds. The structures of the new compounds were elucidated on the basis of spectroscopic data interpretation. Wallitaxane D (<b>4</b>) was identified as an opened oxetane-type taxoid having the first naturally occurring C­(H)-20 acetal group, while wallitaxanes E (<b>5</b>) and F (<b>6</b>) are representative of the rare <i>abeo</i>-taxoid class. The isolated compounds were evaluated for their α-glucosidase inhibitory activity and for cytotoxicity against the HeLa human cervical cancer cell line. In the present work, taxanes were found to exhibit α-glucosidase inhibitory activity for the first time, and wallitaxane A (<b>1</b>) showed the most potent effect, with an IC₅₀ value of 3.6 μM. In turn, 7-<i>epi</i>-taxol (<b>16</b>) and 7-<i>epi</i>-10-deacetyltaxol (<b>17</b>) showed IC₅₀ values of 0.05 and 0.085 nM, respectively, against HeLa cells

Constituents of the Rhizomes of <i>Boesenbergia pandurata</i> and Their Antiausterity Activities against the PANC‑1 Human Pancreatic Cancer Line

Human pancreatic cancer cell lines have a remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions represents a novel antiausterity strategy in anticancer drug discovery. In this investigation, a methanol extract of the rhizomes of <i>Boesenbergia pandurata</i> showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC₅₀ value of 6.6 μg/mL. Phytochemical investigation of this extract led to the isolation of 15 compounds, including eight new cyclohexene chalcones (<b>1</b>–<b>8</b>). The structures of the new compounds were elucidated by NMR spectroscopic data analysis. Among the isolated compounds obtained, isopanduratin A1 (<b>14</b>) and nicolaioidesin C (<b>15</b>) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 1.0 and 0.84 μM, respectively

Chemical Constituents of <i>Mangifera indica</i> and Their Antiausterity Activity against the PANC‑1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cell lines such as PANC-1 have an altered metabolism, enabiling them to tolerate and survive under extreme conditions of nutrient starvation. The search for candidates that inhibit their viability during nutrition starvation represents a novel antiausterity strategy in anticancer drug discovery. A methanol extract of the bark of <i>Mangifera indica</i> was found to inhibit the survival of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions with a PC₅₀ value of 15.5 μg/mL, without apparent toxicity, in normal nutrient-rich conditions. Chemical investigation on this bioactive extract led to the isolation of 19 compounds (<b>1</b>–<b>19</b>), including two new cycloartane-type triterpenes, mangiferolate A (<b>1</b>) and mangiferolate B (<b>2</b>). The structures of <b>1</b> and <b>2</b> were determined by NMR spectroscopic analysis. Among the isolated compounds, mangiferolate B (<b>2</b>) and isoambolic acid (<b>12</b>) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under the nutrition-deprived condition with PC₅₀ values of 11.0 and 4.8 μM, respectively