The tribe Calostemmateae of Amaryllidaceae, consisting of Calostemma and Proiphys and restricted to Australia, Malaysia and the Philippines, has sparsely investigated chemistry and biological activity. Proiphys has not previously been investigated for chemistry and none of the genera have been investigated for biological activity. We here report on alkaloids and acetylcholinesterase inhibition of Calostemma purpureum R.Br. and Proiphys amboinensis (L.) Herb. From P. amboinensis, haemanthamine and lycorine were isolated; from C. purpureum, incartine, lycorine and galanthine were identified. Haemanthamine and incartine showed no acetylcholinesterase inhibition at concentrations of 50 mg/mL, whereas the IC50 values of lycorine and galanthine were 22.3 mM (6.4 1.2 mg/mL) and 63.1 mM (20.1 1.1 mg/mL) respectively. All the isolated alkaloids have been found in other tribes and do not add significantly to our understanding of the origin and relationship of Australasian tribe Calostemmateae. Instead, the pattern of common alkaloid chemistry suggests that the defensive chemistry of Australasian Amaryllidaceae has been conserved in spite of the tribe being geographically isolated since the breakup of Gondwanaland in the late cretaceous.