目的：研究合欢皮的化学成分及活性。方法：用现代色谱法分离合欢皮皂苷，用化学和现代波谱法，主要是二维核磁共振技术鉴定结构。结果及结论：分离并鉴定了一个新三萜皂苷，结构为３Ｏ［βＤ吡喃木糖基（１→２）αＬ吡喃阿拉伯糖基（１→６）βＤ吡喃葡糖基］２１Ｏ｛（６Ｓ）２反式２羟甲基６甲基６ＯβＤ吡喃木糖基２，７辛二烯酰基｝金合欢酸２８ＯβＤ吡喃葡糖基（１→３）［αＬ呋喃阿拉伯糖基（１→４）］αＬ吡喃鼠李糖基（１→２）βＤ吡喃葡糖基酯，命名为合欢皂苷Ｊ２０（ＪｕｌｉｂｒｏｓｉｄｅＪ２０）。 Objective: To study the chemical composition and activity of Albizia julibrissin. METHODS: Separation of Albizia saponin was performed by modern chromatography. Structures were identified by chemical and modern spectroscopy, mainly by two-dimensional nuclear magnetic resonance techniques. RESULTS AND CONCLUSION: A new triterpene saponin was isolated and identified and its structure was 3-O-β-D-xylopyranosyl (1→2)-α-L-pyrantosyl-(1→ 6) β-D-glucopyranosyl 21O{(6S)2trans2hydroxymethyl6methyl6OβDpyranoyl Glycosyl-2,7-octadienoyl}-anisole 28OβD-glucopyranosyl(1→3)αLarabinofuranosyl(1→4) ] α   L 吡 吡 吡 吡 鼠 鼠 鼠 鼠 鼠 ( (      glucopyranyl ester, named as Jupiter saponin J20 (JulibrosideJ20).