1 research outputs found
Diarylheptanoids from Rhizomes of Alpinia officinarum Inhibit Aggregation of α‑Synuclein
Two
new diarylheptanoids, alpinin A (<b>1</b>) and alpinin
B (<b>2</b>), together with 18 known diarylheptanoids (<b>3</b>–<b>20</b>), were isolated from the rhizomes
of Alpinia officinarum. Their structures
were elucidated by comprehensive spectroscopic analysis, including
high-resolution mass spectrometry, infrared spectroscopy, and one-
and two-dimensional nuclear magnetic resonance spectroscopy. Structurally,
alpinin A is a new member of the small family of oxa-bridged diarylheptanoids
and contains the characteristic 2,6-<i>cis</i>-configured
tetrahydropyran motif (C<sub>1</sub>–C<sub>5</sub> oxa bridge).
The absolute configuration of alpinin A was confirmed by asymmetric
total synthesis of the enantiomer (<i>ent</i>-<b>1</b>), corroborating the assignment of the molecular structure. The absolute
configuration of alpinin B was determined on the basis of the analysis
of the circular dichroism exciton chirality spectrum. We evaluated
the inhibitory activity of all isolated diarylheptanoids against α-synuclein
aggregation at 10 μM. Alpinins A and B significantly inhibited
α-synuclein aggregation by 66 and 67%, respectively