4 research outputs found
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>) (IC<sub>50</sub>, 0.013 μM), was 3000 times more active as
a tyrosinase inhibitor than a positive control, kojic acid (IC<sub>50</sub>, 44.6 μM)
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 PC<sub>50</sub> 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
PC<sub>50</sub> 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 PC<sub>50</sub> 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 PC<sub>50</sub> values of 11.0 and 4.8 μM, respectively
α‑Glucosidase Inhibitory and Cytotoxic Taxane Diterpenoids from the Stem Bark of <i>Taxus wallichiana</i>
From a CH<sub>2</sub>Cl<sub>2</sub> 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 CÂ(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 IC<sub>50</sub> 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
IC<sub>50</sub> values of 0.05 and 0.085 nM, respectively, against
HeLa cells