Galtonosides A-E: Antiproliferative and Antiplasmodial Cholestane Glycosides from Galtonia regalis

Donna Huber on March 31, 2020

Photograph of a yellow Galtonia regalis flower next to two chemical structures of cholestane glycosides with labeled R groups, showing IC50 values for PF/Dd2 cell assays.

Photograph of a yellow Galtonia regalis flower next to two chemical structures of cholestane glycosides with labeled R groups, showing IC50 values for PF/Dd2 cell assays.

An extract of Galtonia regalis from the Natural Products Discovery Institute showed moderate antiplasmodial activity, with an IC50 value less than 1.25 μg/mL. The two known cholestane glycosides 1 and 2 and the five new cholestane glycosides galtonosides A–E (3–7) were isolated after bioassay-directed fractionation. The structures of the new compounds were determined by interpretation of their NMR and mass spectra. Among these compounds, galtonoside B (4) displayed the most potent antiplasmodial activity, with an IC50 value of 0.214 μM against the drug-resistant Dd2 strain of Plasmodium falciparum.

Yongle Du, Brooke A. Martin, Ana Lisa Valenciano, Jason A. Clement, Michael Goetz, Maria B. Cassera, David G. I. Kingston. J Nat Prod. 2020 Mar 31. doi: 10.1021/acs.jnatprod.9b01064.

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