Isolation and identification of a flavonoid compound and in vivo lipid-lowering properties of Imperata cylindrica

Cogon grass (Imperata cylindrica/I. cylindrica) of the Gramineae family is found abundantly in nature, and the roots of this plant possess several beneficial biological properties. The present study aimed to isolate and identify flavonoid compounds from cogon grass roots and examine their potential as hypocholesterolemic agents. The flavonoid compound was isolated using a maceration method, followed by gravity column chromatography until a pure compound was obtained. The molecular structure of the isolated compound was determined using (1)H-nuclear magnetic resonance (NMR) and (13)C-NMR spectroscopy. An in vivo lipid-lowering test used a randomized post-test only control group experimental design in rats with hypercholesterolemia. The animals were divided into four groups: K0, negative control; K1, positive control; K2, ethanol extract treated group; and K3, ethyl acetate fraction treated group, and the lipid profiles were examined at the end of the study. The isolated compound, 7,3',5'-trimethoxyflavonol, was collected in yellow powder form; was shown to be a flavonoids and was comprised of 18 carbon atoms and 16 hydrogen atoms. In vivo tests demonstrated that 15 mg/200 g body weight (BW) of an ethanol extract significantly lowered total cholesterol levels (P=0.001) but did not lower low-density lipoprotein (LDL) (P=0.109) and high-density lipoprotein (HDL) levels (P=0.003). The fraction of ethyl acetate administered at 15 mg/200 g BW was capable of lowering the total cholesterol levels significantly (P=0.002) and lowered LDL levels (P=0.006) but was unable to increase HDL levels (P=0.190). The in vivo tests showed that the ethyl acetate fraction of I. cylindrica reduced total cholesterol and LDL levels more effectively than the ethanol extract, but did not affect HDL levels in rats with hypercholesterolemia.