Studies On Triterpenoid Saponins Of The Rhizomes Of Anemone Flaccida

Anemone flaccida Fr. Schmidt (Ranunculaceae) is a perennial herb widelydistributed throughout southern China. The rhizomes of A. flaccida, commonlyknown as “Di-Wu” in China, are used as a Chinese folk medicine for the treatment ofrheumatic, arthralgia, and cancer. Previous phytochemical studies showed thattriterpenoid saponins were the main chemical components of this plant. Recently, inChina, a saponin rich fraction of the rhizomes of A. flaccida is undergoing phase Ⅲclinical trial for the treatment of rheumatoid arthritis due to its significantanti-rheumatic, anti-inflammatory, and immunomodulatory activities.As part of our ongoing program on the bioactive saponin constituents fromChinese medicinal plants, as well as with the purpose to find out theanti-inflammatory active principle of the title plant, we carried out a systematicphytochemical investigation on this plant. As a result, twenty-one triterpenoidsaponins were isolated by using various chrmatographic techniques, and the structureswere elucidated on the basis of spectroscopic analysis and chemical methods as3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl3β-hydroxy-18α,19α-urs-20-en-28-oic acid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester(flaccidoside IV, AF-1),3-O-α-L-rhamnopyranosyl-(1→2)-β-D-quinovopyranosylolean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (flaccidoside V, AF-2),3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (flaccidoside VI, AF-3),3-O-β-D-xylopyranosyl olean-12-en-28-oic acid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (flaccidoside VII, AF-4),3-O-β-D-glucopyranosyl olean-12-en-28-oic acid28-O-β-D-glucopyranosyl ester (lucyoside H, AF-5),3-O-β-D-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl olean-12-en-28-oic acid28-O-β-D-glucopyranosyl ester (giganteasides G, AF-6),3-O-β-D-rhamnopyranosyl- (1→2)-α-L-arabinofurnosyl olean-12-en-28-oic acid28-O-β-D-glucopyranosyl ester(mateglycoside D, AF-7), olean-12-en-28-oic acid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (asteryunnanoside F, AF-8),3-O-β-D-glucuronopyranosylolean-12-en-28-oic acid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester(hemsgiganoside B, AF-9),3-O-β-D-rhamnopyranosyl-(1→2)-β-D-glucopyranosylolean-12-en-28-oic acid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester(AF-10),3-O-β-D-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl olean-12-en-28-oicacid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (anhuienoside C,AF-11),3-O-β-D-rhamnopyranosyl-(1→2)-α-L-arabinofurnosyl olean-12-en-28-oicacid28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (AF-12), olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (cussonoside B, AF-13),3-O-β-D-glucopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (nipponoside B, AF-14),3-O-β-D-glucuronopyranosylolean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (AF-15),3-O-β-D-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (anhuienosides E, AF-16),3-O-β-D-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester(flaccidoside II, AF-17),3-O-β-D-glucopyranosyl-(1→2)-β-D-xylopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (flaccidoside III, AF-18),3-O-β-D-rhamnopyranosyl-(1→2)-α-L-arabinofurnosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (hederasaponin B,AF-19),3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-gluco-pyranosyl ester (AF-20), and3-O-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl olean-12-en-28-oic acid28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (anhuienoside F, AF-21). Among them, AF-1~AF-4are four new triterpenoid saponins, and AF-6~AF-8, AF-11, AF-12, AF-20and AF-21were isolated from this plant for the firsttime.The inhibitory activity of the isolated saponins on LPS-induced NO productionwere tested in macrophage RAW264.7cell. Among them, AF-2, AF-3, AF-7, AF-11,AF-17, AF-19and AF-21can significantly inhibit the release of NO.