Saponins, the glycosides of steroids or triterpenes, are widely distributed in plants and animals. 1) They exist in relatively high quantities in many significant food and beverage plants, including oats, peanuts, soybeans, lentils, mung beans, garlic, onions, spinach, asparagus, jujube, quillaja and tea. Saponins also are generally found as active constituents in many well known oriental herbal medicines such as ginseng, notoginseng, licorice, horse chestnut, red clover, senegae, and primula.2) Many previous studies reveal that saponins show various physiological and pharmacological activities, such as anti-cancer, anti-inflammatory, cardiovascular, and cytotoxic activities.3,4) The oligosaccharides integrated into the saponins have a very important role in their bioactivity and thus the interest in this sugar unit is rapidly increasing. For example, when the ether-linked tetrasaccharide was removed from julibrosides, its cytotoxicity dramatically decreased. We recently reported Pulsatilla saponin5) In addition, a total 17 triterpenoid saponins including six new saponins were isolated from Pullsatilla koreana N. root and the structure-activity relationships of antitumoral saponins was published.6,7) Among them, Pullsatilla saponin D (1, inhibition ratio (IR): 66.9% against LLC lung carcinoma xengraft model at 6.0 mg/kg/d i.p., ED 50 3.04-13.17 mM) and oleanolic ]-a -Larabinopyranoside, at C-3 position enhances the activity. It has been postulated that the linked trisaccharide improves the bioavailability in tumor tissue in vivo. Therefore, this moiety could be utilized as a promoiety for the increment of the activity of other antitumoral compounds and their solubility in water as shown in Fig. 1. Indeed, glucose has been integrated into anticancer agents as a conjugate for the improvement of their activity since cancer cells have increased rate of glucose metabolism compared with healthy cells and over-expression of 11) This approach has been also applied to pep- A trisaccharide found in triterpenoid saponins isolated from Pullsatilla roots appears as an important promoiety for the enhancement of anticancer activity of their aglycones. Thus a facile synthetic method for a trisaccharide moiety, allyl-2,3,4-tri-O-benzoyl-a a-L-rhamnopyranosyl-(1→ →2)- [2,3,4,6-, has been firstly developed through the regio-and stereoselective glycosylations from arabinose in total 16% yield via route 2 (eight steps). In this synthetic procedure, the protection of anomeric -OH of L-arabinose with equatorially oriented allyl group unlike with the axial 4-methoxybenzyl protecting group well promoted glycosyl bond formation between a a-L-rhamnopyranosyl trichloroacetimidate and 2-OH of arabinose. As expected, the synthesized trisaccharide moiety 3 has no cytotoxicity (ED 50 : Ͼ100 m mM) against three human cancer cell lines (A-549, SK-OV-3, and SK-MEL-2), respectively.