PharmacyMedicinal ChemistryPharmacologyCancer PharmacologyDrug DiscoveryStructure-activity RelationshipsMedicinal PlantsNatural Product Drug DiscoveryPlant Natural Product BiosynthesisCancer Cell Line Models
Bioactivity-guided fractionation led to the isolation of a new steroidal saponin, orbiculatoside B, together with a pair of furostanol saponins, protobioside and methyl protobioside, from the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata. The new Compound was identified to be isonarthogenin 3 - O - alpha - L - rhamnopyranosyl (1-->2) - [alpha - L - rhamnopyranosyl - (1 --> 4)] - beta - D - glucopyranoside by various NMR techniques in combination with chemical methods. The three saponins showed strong activity against Pyricularia oryzae, and were cytotoxic to cancer cell line K562, HCT-15, A549, and A2780a in vitro.