Angiogenic effect of motherwort (Leonurus japonicus) alkaloids and toxicity of motherwort essential oil on zebrafish embryos

There is growing evidence that motherwort (Leonurus japonicus Houtt.), and Chinese patent medicines derived from motherwort, alleviate postpartum uterine subinvolution, as well as the effects on myocardial and cerebral ischemic injuries. We hypothesized that these beneficial effects of motherwort may be related to angiogenesis. To test this hypothesis, we investigated the angiogenic effects of motherwort total alkaloids and essential oil, as well as their respective primary components, on zebrafish embryos. Motherwort total alkaloids significantly increased angiogenesis in transgenic Tg (flk1: EGFP) zebrafish embryos treated with sunitinib, as did stachydrine, the most abundant alkaloid produced by motherwort. Unexpectedly, motherwort essential oil was toxic to zebrafish embryos. Our results indicated, for the first time, that motherwort alkaloids were potent angiogenic agents, while even low concentrations of motherwort essential oil were toxic. As angiogenesis is a critical aspect of postpartum recovery, our results provide evidence for traditional application of motherwort water decoction and its Chinese patent medicines (e.g. motherwort injection) to promote postpartum recovery.