Seven new tropane alkaloids, including
five monomeric (1–5), one dimeric
(6), and one trimeric
(7) 3α-nortropane ester, along with two known monomeric
nortropane alkaloids (8 and 9), were isolated
from the leaves and bark of Pellacalyx saccardianus. Their structures, including the absolute configuration of the enantiomeric
pair of (±)-6, were elucidated by comprehensive
spectroscopic analyses. Alkaloids 6 and 7 showed cytotoxicity toward human pancreatic cancer cell lines (AsPC-1,
BxPC3, PANC-1, and SW1990). Alkaloids 1, 4, and 9 induced a smooth muscle relaxation effect comparable
to that of atropine (Emax 106.1 ±
7.5%, 97.0 ± 5.2%, 100.9 ± 1.4%, 111.7 ± 1.7%, respectively)
on isolated rat tracheal rings.