Dracorhodin, the main component in sanguis draconis, is a flavylium compound belonging to the anthocyanin family. Dracorhodin can induce vasodilatation[1].
References
[1] Zhang Y, et al. Effects of Sanguis Draconis on Perforator Flap Survival in Rats. Molecules. 2016 Sep 26;21(10). DOI:10.3390/molecules21101262