目的：探讨紫草素最佳提取工艺条件。方法选取紫草1 kg，采用正交实验方法，选用乙醇、石蜡作为复合溶媒，用回流的方法提取萘醌色素类物质......

A new approach for asymmetric synthesis of alkannin and shikonin is presented. The chiral centers of the targets were in......