Catalpol is an iridoid glycoside that has been isolated from R. glutinosa and has diverse biological activities, including anti-apoptotic, pro-angiogenic, and radioprotective properties.¹ It protects against mitochondrial pathway-dependent apoptosis in PC12 rat adrenal pheochromocytoma cells and H9c2 rat embryonic ventricular myocardial cells when used at a concentration of 10 µM.^2,3 Catalpol pretreatment reduces apoptosis and improves viability in AHH-1 human lymphocyte cells exposed to ionizing radiation and reduces intestinal damage induced by radiation in mice when used at concentrations and doses ranging from of 25 to 100 µg/ml and 25 to 100 mg/kg, respectively.⁴ In a rat model of stroke, catalpol (5 mg/kg, i.p.) increases the expression of erythropoietin and VEGF and improves angiogenesis in the brain.⁵