2.1. Phytochemical studies
2.1.1. Identification of phenolic acids by HPLC
Phenolic compounds of Pteranthus dichotomus plant sample were extracted [9], identified on
a Hewlett-Packard HPLC (Model 1100), using a hypersil C18 RP column (250 x 4.5 mm) with 5 µm
particle size and comparing their relative retention times with those of standard mixture
chromatogram. The concentration was calculated on the basis of peak area measurements, and then
converted to µg phenolic g-1 dry weight.
2.1.2. Isolation and identification of flavonoid compounds:
Extraction and purification
The air-dried powder of Pteranthus dichotomus Forssk. (1 kg) was extracted by percolation in
70 % methanol and filtered off; the marc lifted was extracted by the same way (this process repeated
four times).
The combined methanol extracts were concentrated under reduced pressure at temperature not
exceeding 40 oC till dryness (230 g), dissolved in hot water and filtered to remove chlorophyll and
lipoidal matters, concentrated till dryness and then dissolved in small amount of methanol with stirring
to remove salts; concentrated till dryness. The dried extract was dissolved in small amount of water
(500 ml) and extracted successively using diethyl ether, chloroform, ethyl acetate and n-butanol by
separating funnel. Each extract was dried over anhydrous sodium sulphate and concentrated again as
before, to give 2.2 g, 1.2 g, 8.5 g and 22 g from diethyl ether, chloroform, ethyl acetate and n-butanol
extracts respectively.