中文摘要：

目的研究碎米花杜鹃Rhododendron spiciferum叶的化学成分及其免疫活性。方法利用多种色谱技术进行化合物的分离纯化，通过各种波谱方法鉴定其化学结构，并用MTT法测定化合物对小鼠脾淋巴细胞增殖的影响。结果分离鉴定了12个已知的黄酮类化合物，分别为槲皮素-3-O-α-L-阿拉伯呋喃糖苷（1）、槲皮素-3-O-α-L-鼠李吡喃糖苷（2）、二氢槲皮素-O-α-阿拉伯吡喃糖苷（3）、落新妇苷（4）、5，7，4＇-三羟基-二氢黄酮醇--O-α-L-鼠李吡喃糖苷（5）、柚皮素（6）、（2S）-5，7，4＇-三羟基-8-甲基黄烷酮（7）、epicatechin-（2β→O→7，4β→8）-ent—epicatechin（8）、花青素A-1（9）、bis-8，8＇-catechinylmethane（10）、儿茶素（11）、表儿茶素（12）。化合物8、9、11在一定浓度范围内单独或者协同非特异性丝裂原（ConA或LPS）作用均能显著增强小鼠脾淋巴细胞增殖能力（P〈0．05，0．01或0．001）。结论碎米花杜鹃的化学成分为首次报道。相关免疫活性实验表明，化合物8、9、11具有一定的免疫增强作用。

英文摘要：

Objective To study the chemical constituents from the leaves of Rhododendron spiciferurn and their immunomodulatory activities. Methods The chemical constituents were isolated by various chromatography techniques and their structures were elucidated on the basis of spectroscopic data. The immunomodulatory activity of some compounds was examined by Balb/c mouse spleen lymphocyte proliferation through MTT. Results Twelve known flavonoids were isolated and identified as： quercetin-3-O-α-L-arabinfuranside （ 1）, quercetin-3-O-α-L-rhamnopyranoside （2）, trans-taxifolin-3-O-α-arabinopyranoside （3）, astilbin （4）, 3-O-rhamnoside engeletin （5）, naringenin （6）, （2S）-5, 7, 4＇-trihydroxy-8-methylflavanone （7）, epicatechin-（2β→O→7,4β→8）-ent-epicatechin （8）, proanthocyanidin A-1 （9）, bis-8, 8＇-catechinylmethane （10）, catechin （11）, and epicatechin （12）. The results showed that compounds 8, 9, and 11 alone or combined with ConA or LPS could significantly enhance the proliferation of spleen lymphocytes in a certain dose range. Conclusion This is the first report on the chemical constituents from R. spiciferurn. Compounds 8, 9, and 11 are found to be effect on increasing immunomodulatory activity.