Dereplication of Bioactive Agave Saponin Fractions: The Hidden Saponins

The good phytotoxicity and selectivity against weeds versus tomato or cress make saponin-rich fractions from Agave macroacantha, A. colorata, A. parryi, and A. parrasana attractive candidates as bioherbicides. The saponin contents have only previously been reported for A. macroacantha, and as a consequence, simultaneous dereplication has been performed on saponin-rich fractions from the other plants by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. This strategy enables the identification of a total of 26 saponins, 14 of which have been described previously and 12 of which are proposed as new saponins. They include isomers and a new sugar chain with a β-d-apiofuranose unit. The method is corroborated by the isolation of eight dereplicated saponins from A. colorata.