in vivo cardiovascular effects of L leonurus diterpenoids

This study assessed the effect of five diterpenoid compounds (dubiin, saponified dubiin, DC8, DC9 and marrubiin) isolated from Leonotis leonurus (Lamiaceae) on blood pressure and heart rate in the anaesthetized normotensive Wistar rat model. L. Leonurus is a medicinal plant indigenous to southern Africa, used in traditional medicines for the treatment of various diseases including cardiovascular diseases, with extracts of the plant leaves reported to produce varying cardiovascular effects in vitro and in vivo. Our hypothesis was that the cardiovascular effects reported with extracts of the plant were due to these diterpenoid compounds previously isolated from the plant. Changes to blood pressure and heart rate with the IV administration of these compounds were recorded in anaesthetized male Wistar rats via a cannulated femoral artery connected to a BP transducer, BP amplifier and a PowerLab. The data presented shows replicate (6) values for blood pressure and heart rate after 3 minutes of infusion of the test compound. Mean and SEM are presented at the bottom of each dose column as well as results of ANOVA testing for significant differences to the control (saline) and positive control (dobutamine 60 ug/kg). Dubiin, DC 8, DC 9 and saponified dubiin produced dose-dependent increases in blood pressure and heart rate, while marrubiin produced dose dependent decreases in blood pressure, with non-significant changes to heart rate