Study On Steroidal Saponins From The Rhizome Of Paris Polyphylla Smith Var. Yunnanesis

The rhizoma Paridis (Chonglou) is the dry rhizome of the Paris polyphylla Smith var. yunnanensis or Paris polyphylla Smith var. chinesis of the Liliaceae family. It has played an important role in traditional medicine development for tumors, bleeding, immunity adjustment, analgesia and so on. Steroidal saponins are the chief active ingredients in it. Furthermore, it has been reported that the activities of steroidal saponins are associated with the structures of the aglycons and sugar units. So, it's necessary to separate and identify more single compounds for the screening to study the structure-activity relationships to set foundation for the development of the new medicines with higher efficacy and lower toxicity.In this paper, our systematic phytochemical investigation of the steroidal saponins from Paris polyphylla Smith var. yunnanensis led to the isolation of 6 new steroidal saponins (Compounds 1, 2, 8, 12a, 12b and 15), together with 18 known steroidal saponins, wherein 2 steroidal saponins (Compounds 20 and 23) were firstly isolated from the genus Paris, and 3 steroidal saponins (Compounds 3, 7 and 16) were firstly isolated from Paris polyphylla Smith var. yunnanensis, by repeated column chromatography on macroporous resin (SP 825), silica gel, octadecylsilanized silica gel (ODS) and preparative HPLC. On the basis of chemical evidences and spectral analysis, structures of the 24 compounds were elucidated as follows:26-O-β-D-glucopyranosyl-(25R)-5-en-furost-3β, 17α, 22α, 26-tetraol-3-O-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Paris-yunnanoside A, 1), 26-O-β-D-glucopyranosyl-(25R)-Δ^{5(6), 17(20)}-dien-16, 22-dione-furost-3β, 26-diol-3-O-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Parisyunnanoside F, 2), 26-O-β-D-glucopyranosyl-(25R)-5-en-furost-3β, 17α, 22α, 26-tetraol-3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyrano-syl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Th, 3), 26-O-β-D-glucopyranosyl-(25R)-5-en-furost-3β, 22α, 26-triol-3-O-α-L-rhamnopyranosyl-(1→4) -α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Dichotomin, 4), 26-O-β-D-glucopyranosyl-(25R)-5-en-furost-3β, 22α, 26-triol-3-O-α-Z-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Parisaponin I, 5), 26-O-β-D-glucopyranosyl-(25R)-5-en-furost-3β, 22α, 26-triol-3-O-β-D-glucopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Protogracillin, 6), 26-O-β-D-glucopyranosyl-(25R)-Δ^{5(6) 20(22)}-dien-furost-3β, 26-diol-3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamn-opyranosyl-(1→2)]-β-D-glucopyranoside (Pseudoproto-Pb, 7), 26-O-β-D-glucopy-ranosyl-(25R)-Δ^5(6),20(22)-dien-furost-3β, 26-diol-3-O-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyra-noside (Parisyunnanoside B, 8), (25R)-5-en-spirost-3β, 17α-diol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (Tb, 9), (25R)-5-en-spirost-3β, 17α-diol-3-O-a-L-arabinofuranosyl-(1→4)-[α-L-rhamnopy-ranosyl-(1→2)]-β-D-glucopyra-noside (Chonglouoside H, 10), (25R)-5-en-spirost-3β, 17α-diol-3-O-β-D-glucopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-gluco-pyranoside (11), (25R)-spirost-5-en-3β, 7β-diol-3-O-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Parisyunnanoside D, 12a), (25R)-spirost-5-en-3β, 7α-diol-3-O-α-L-arabinofuranosyl-(1→4)-[α-Z-rhamnopyrano-syl-(1→2)]-β-D-glucopyranoside (Parisyunnanoside E, 12b), (25R)-5-en-spirost-3β, 17α-diol-3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rham-nopyranosyl-(1→2)]-β-D-glucopyranoside (Tg, 13), (25R)-Δ⁷⁽⁸⁾-en-spirost-3β, 5α, 6α-triol-3-O-β-D-glucopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucop-yranoside (Parisvientnaside A, 14), (25R)-spirost-5-en-3β, 12α-diol-3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)- [α-L-rhamnopyranosyl-(1→2) ]-β-D-glucopyranoside (Parisyunnanoside C, 15), (25R)-5-en-spirost-3β, 17α-diol-3-O-α-L-arabinofuranosyl-(1→4)-β-D-glucopyranoside (16), (25R)-5-en-spirost-3-O-α-L-arabinofuranosyl-(1→4)-β-D-glucopyranoside (17), (25R)-5-en-spirost-3β, 17α-diol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (Prosapogenin A of Dioscin, 18), (25R)-5-en-spirost-3-O-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopy-ranosyl-(1→2)]-β-D-glucopyranoside (Pa, 19), (25R)-5-en-spirost-3-O-α-L-rhamno-pyranosyl-(1→5)-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranos-yl-(1→2)] -β-D-glucopyranoside (Reclinatoside, 20), (25R)-spirost-5-en-3-O-α-Z-rhamnopyranosyl- (1→4)-α-L-rhamnopyranosyl-(1→4)- [α-L-rhamnopyranosyl-(1→2)] -β-D-glucopyran-oside (Pb, 21), (25R)-5-en-spirost-3-O-β-D-glucopyranosyl-(1→3)-[α-L-rhamno-pyranosyl-(1→2)]-β-D-glucopyranoside (Gracillin, 22), and (25R)-5-en-spirost-3-O-β-D-glucopyranosyl-(1→5)-α-L-arabinofuranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (Loureiroside, 23), respectively.The isolated compounds were evaluated for their cytotoxic activities against HL-60 human promyelocytic leukemia cells and their platelet aggregation activities. The result of the cytotoxic activitiy screening indicated that most of the spirostanol saponins showed the cytotoxic activitiy, wherein Pb showed the strongest activity with an IC₅₀ at 0.13μg/mL, while furostanol saponins were inactive. On the basis of cytotoxic activity assay, we primarily approached the structure-activity relation and found that the spirostanol framework of the aglycon and the terminalα-L-rhamnopyranosyl with a 1→2 C-bond linkage to sugar chain of saponins at C-3 position are necessary for steroidal saponins with high cytotoxic activities. Furthermore, the hydroxyl groups on the aglycon showed inhibitory action on the cytotoxic acivity. The findings all above set foundation for the molecular design and development of the antitumor new medicines.