The genus Alstonia,which belongs to the family Apocynaceae,
comprises about 60 species and is mainly distributed in Asia
and South America [1,2]. Among them, 8 species naturally
occur in China [3]. Plants of the family Apocynaceae have been
proven to be good sources of monoterpenoid indole alkaloids
[4–8]. Monoterpenoid indole alkaloids, which originate from
the condensation of tryptophan with secologanin to give
strictosidine, have attracted the interest of many researchers
due to their complicated structures and potent biological
activities [9–15]. This type of alkaloids possesses anticancer,
antibacterial, antifertility, and anti-tussive activities [16–20].
Galanthamine is a long-acting, selective, reversible and competitive
acetylcholine esterase inhibitor that has been approved
for use in the European Union and the United States for
the treatment of Alzheimer's disease (AD). Alstonia rupestris
Kerr is usually endemic in the west part of the Guangxi