Alkaloids from Croton echinocarpus Baill.: Anti-HIV potential

•Several species have been used in traditional medicine in Brazil.•Croton L. is a genus of Euphorbiaceae with approximately 1300 species.•Hydroalcoholic extract of Croton echinocarpus afforded two alkaloids.•Corydine and Norisoboldine were efficient on inhibiting RT activity.•Norisoboldine showed IC50 of 153.7 μg mL- 1 against RT-HIV1.

Croton belongs to the Euphorbiaceae genus, one of the major Angiosperms families, and is widely distributed throughout the world, especially in the tropics. In this study, the hydroalcoholic extract (70% EtOH) of Croton echinocarpus leaves afforded two alkaloids: corydine and norisoboldine, and their structures were established by spectroscopic data interpretation (UV, IR, NMR and LREIMS). Both alkaloids displayed significant in vitro anti-HIV potential, inhibiting 40% of the HIV-1 reverse transcriptase enzyme activity at a concentration of 100 μg mL- 1 of norisoboldine and 450 μg mL- 1 of corydine. Corydine showed IC50 of 356.8 μg mL- 1, while norisoboldine was more efficient on inhibiting the RT activity, showing IC50 of 153.7 μg mL- 1.