Effect of 3-Dihydrocadambine isolated from wild Cinchona (Anthocephalus chinensis) leaves on blood pressure and heart rate in tree shrew (Tupaia glis)

Abstract

The effect of 3 ∝ -dihydrocadambine, indole glycosidic alkaloid (ALK), isolated from Anthocephalus chinensis leaves on blood pressure and heart rate was investigated in tree shrews. This ALK at various doses were dissolved in 10% polyethylene glycol (PEG) in normal saline for intravenous injection (IV) which was found that 6.4 mg/kg B.W. was the optimal effective dose; in case of intraventricular injection (VENT), 0.4 to 3.2 mg/kg B.W. were dissolved in 20% PEG in artificial cerebrospinal fluid (aCSF). It was found that after ALK injection, systemic arterial pressure and heart rate were decreased significantly when compared to those control by both routes of administration (p < 0.05). However, there was a difference in the pattern of hemodynamic change between the two routes of administration. The IV injection decreased systemic blood pressure immediately (about 40 sec after injection) while by VENT, 20 min delayed decreasing effect was occurred. It was also found that placebo injection of 20% PEG in aCSF itself into the lateral ventricle evoked significant systemic change. When it was compared to the VENT doses of ALK, there was no statistically significant changes between them (p > 0.05). We also observed hypotensive effect of this agent during fastigial pressor response which was induced by fastigial nucleus stimulation, hemodynamic changes of these groups were similar to the basal blood pressure groups, when the same doses were compared. From this study, it may be postulated that this agent, 3 ∝ - dihydrocadambine, has an hypotensive effect which predominant peripheral action.