Flavonoids were isolated by PVPP column chromatography of leaf extracts of Croton floribundus Spreng and C. urucurana Baill. and identified by NMR and co-chromatography with standards. The two species revealed highly distinct flavonoid profiles. C. urucurana, belonging to the phylogenetically basal section Cyclostigma, yielded the flavone C-glycosides vitexin and orientin, quercetin and the O-glycosides quercetin 7-O-rhamnoside, rhamnitrin and rutin, in addition to tiliroside. Instead, C. floribundus, from the more derived section Lasiogyne, yielded no C-glycosides, but a high diversity of classes of flavonols, including kaempferol, three flavonol O-methyl ethers, isoquercitrin, three tri-O-galactosides, in addition to tiliroside and an isorhamnetin-coumaroyl-O-glycoside. The present work is the first report for Croton of two rhamnosides (isolated from C. urucurana). It is also the first report for Euphorbiaceae of two tri-O-glycosides obtained from C. floribundus. The distribution of flavonoids in the two species as determined by HPLC-DAD of extracts of small leaf samples of herbarium specimens is highly similar with the profiles resulting from isolation of compounds from bulky leaf samples. Differences among specimens of the same species were restricted to relative proportions of individual constituents. The results indicate that flavonoid profiles are effective to characterize and distinguish the two species. The present results, combined with literature data, supports the condition of tiliroside as a marker of Croton and the hypothesis of an evolutionary trend in the genus toward the loss of C-glycosides and a progressive complexity of flavonoid profiles.

通过PVPP柱色谱法分离Croton floribundus Spreng和C. urucurana Baill叶提取物的类黄酮。并通过NMR和共色谱法与标准品一起鉴定。这两个物种显示出高度不同的类黄酮谱。C. urucurana属于系统发育基础环节（Cyclostigma），除紫罗兰苷外，还产生了黄酮C-苷Vitexin和Orientin ，槲皮素以及O-苷槲皮素7- O-鼠李糖苷，鼠李木苷和芦丁。取而代之的是，从更衍生的Lasiogyne节中获得的C. floribundus没有产生C-糖苷，但黄酮醇类的多样性很高，包括山ka酚，三种黄酮醇O-甲基醚，异槲皮苷，三种三-O-半乳糖苷，以及鱼苷和异鼠李素-香豆素-O-糖苷。目前的工作是巴豆中两种鼠李糖苷的首次报道（从鼠尾草中分离）。这也是关于大戟科中两种从大花梭菌获得的三-O-糖苷的报道。。通过HPLC-DAD测定的植物标本室小叶样品的提取物中两种植物中类黄酮的分布与从大叶样品中分离化合物所得到的特征高度相似。同一物种标本之间的差异仅限于各个成分的相对比例。结果表明类黄酮有效地表征和区分这两个物种。本研究结果与文献数据相结合，支持将替罗罗糖苷作为巴豆油的标志物，并支持该类向C-糖苷丢失和类黄酮谱的复杂性发展趋势的假设。