Rheediinosides A and B, two antiproliferative and antioxidant triterpene saponins from Entada rheedii

Two triterpenoid saponins have been isolated from the seed kernels of Entada rheedii. Their structures have been established using 1D- and 2D-NMR and mass spectrometry as 3-O-b-D-xylopyranosyl- (1 -3)-O-a-L-arabinopyranosyl-(1 -6)-2-acetylamino-2-deoxy-b-D-glucopyranosylentagenic acid 28- O-b-apiofuranosyl-(1-3)-b-D-xylopyranosyl-(1 -2)-b-D-glucopyranoside (Rheediinoside A, 1) and 3-O-b-D-glucopyranosyl-(1 -3)-O-[b-D-xylopyranosyl-(1-3)-a-L-arabinopyranosyl-(1 -6)]-2-acetylamino- 2-deoxy-b-D-glucopyranosylentagenic acid 28-O-b-apiofuranosyl-(1-3)-b-D-xylopyranosyl- (1-2)-b-D-glucopyranoside (Rheediinoside B, 2). Compounds 1 and 2 were tested for their antiproliferative activity against T98G, A431, PC3 and B16-F1 cell lines, and further for their antioxidant properties. Moderate cytotoxic potency and antioxidant properties were found for these compounds whereas Rheediinoside B was in all assays more active than Rheediinoside A.