Structural Elucidation of Alkaloids from Aerial Parts of Rivea hypocrateriformis and Their Antihemolytic and Cytotoxic Activity

Two new alkaloids, designated as hypocretine 1 and 2, have been extracted from the aerial parts of Rivea hypocrateriformis, and their structures were established as 1-(4-(((1R,5S,6R)-(4-acetyl-2,6-dibutylphenoxy)-8-methyl-8-azabicyclo[3.2.1]octan-6-yl)oxy)-2,6-dibutylphenyl)ethan-1-one and 1-(4-((3-(4-acetyl-2-butyl-6-(4-hydroxybutyl)phenoxy)-8-methyl-8-azabicyclo[3.2.1]octan-6-yl)oxy)-2-butyl-6-(4-hydroxybutyl)phenyl)ethan-1-one. These alkaloids were further characterized by mass and NMR spectral data analysis. Further studies were conducted to evaluate their antihemolytic and cytotoxic activity. The extracted compounds exhibited potent antihemolytic activity against cow erythrocytes. The results of the MTT assay for cytotoxicity revealed the antiproliferative activity of compounds 1and 2 against MCF-7 breast cancer cell line.