The phytochemical investigation of the hexane and methanol extracts from the bark of Duguetia pycnastera Sandwith (Annonaceae) afforded seven known compounds, two asarone-derived phenylpropanoids and five isoquinoline-derived alkaloids. The asarones, γ-asarone (1-allyl-2,4,5-trimethoxybenzene) and 2,4,5-trimethoxy-styrene were isolated of the hexane extract while the aporphine alkaloids, O-methylmoschatoline, lysicamine, nornuciferidine, and guatterine N-oxide, and the benzyltetrahydroisoquinoline alkaloid, (S)-reticuline were isolated of the alkaloid fraction of the methanol extract. This is the first report of these compounds in D. pycnastera. γ-Asarone is being reported for the first time in the Annonaceae. Nornuciferidine is described for the second time in the Annonaceae while guatterine N-oxide is the third register. The structures of the isolated compounds were established by extensive analyses using 1D and 2D NMR spectroscopy in combination with MS. The cytotoxic activity of the isolated compounds (except for nornuciferidine) was evaluated against cancer and non-cancerous cell lines, in which lysicamine was the most active compound, mainly against HL-60, HepG2, and K562 with IC50 values of 24.40, 28.86 and 38.75 µmol L-1, respectively.

The phytochemical investigation of the alkaloid-rich fraction obtained from the leaves of Guatteria pogonopus Mart. (Annonaceae) allowed the isolation and identification for the first time in this species of: (+)-nornuciferine (1), a mixture of 1 and (+)-anonaine (2), (+)-isocorydine (3), (+)-nuciferine (4), (+)-roemerine (5), (-)-tetrahydropseudocolumbamine (6), a mixture of 6, liriodenine (9) and lysicamine (10), a mixture of 1,2,9-trimethoxy-10-hydroxyaporphine (7) and bulbocapnine (8), 9, 10, and (+)-N-methyllindicarpine (11). Compounds 6, 7, 8, and 11 have not been previously reported in the family Annonaceae. Furthermore, the formerly synthetic 1,2,9-trimethoxyaporfin-10-ol (7) is described for the first time as a natural aporphine alkaloid herein. The chemical structures were established by 1D and 2D NMR as well as in comparison with data previously reported in the literature. The cytotoxic activity of the alkaloids was evaluated against tumor (B16-F10, HepG2, HL-60, and K562) and non-tumor (PBMC) cell lines. Alkaloid 1 presented significant activity against HepG2 cell lines with IC50 of 9.60 µmol L-1 while the mixture of 6, 9 and 10 displayed strong cytotoxic activity against HL-60 and K562 cell lines with IC50 values of 3.41 an 8.50 µmol L-1, respectively.