Effects of various extracts of Garcinia atroviridis in normotensive and spontaneously hypertensive rats

Author

SATIRAH ZAINALABIDIN, JALIFAH LATIP, ENGKU NORBAYA ENGKU MUDA & PADEN MORAT

Proceeding

The 21st Annual Seminar of the Malaysian Natural Product Society.(Herbal Medicine:Natural Products S ciety), Palm Garden, Putrajaya Malaysia.

Date

22/11/2005

Keyword

Garcinia atroviridis, acute hypotensiv, normotensive, SHR, mean arterial pressure

Abstract

Garcinia atroviridis (Guttiferae), known as asam gelugur, is believed among the local Malaysians to lower high blood pressure. A pilot study has showed that chronic treatment using ethyl acetate (EtOAc) and ethanol crude extracts of G. atroviridis decreased the blood pressure (BP) of normotensive rats. This study is to elucidate the acute treatment effect of fractions from EtOAc extract on BP and heart rate (HR) in normotensive and spontaneously hypertensive rats (SHR). The EtOAc crude extract was fractionated through vacuum liquid chromatography (VLC) and the collected fractions were analyzed with thin layer chromatography (TLC) and nuclear magnetic resonance (NMR). Twenty combined fractions (namely F2-F21) were tested (0.001-1 mg/kg BW) to normotensive rats. The results showed that 12 combined fractions gave significant hypotensive effect. The fractions, which gave potent hypotensive effect, were re-tested in SHR. It was found that three fractions, namely F9, F14 and F15, gave significant hypotensive effect in SHR whereby the drop in BP were 17.86±2.72%, 20.79±11.30% and 17.99±2.78%, respectively. However, there was no significant changes in HR for these three fractions. Fraction F8 which gave the highest hypotensive effect on normotensive rat was further purified. It showed hypotensive effect in normotensive rat at much lower dose, i.e. 1 µg/kg BW.  A compound was isolated from F8 and identified as 2-etoxycarbonylmethyl-3-etoxycarbonyl-2-hydroxy-3-propanolide.  This study may justify the use of extract from G. atroviridis fruit as an antihypertensive and could be one of the new promising natural-product-based therapeutic agents for hypertensive patients.