Flavonoids Feasibility Study

3. Phytochemical Screening and Preliminary Screening for Flavonoids

3.1 Alkaloidal analysis (Preliminary Test)

About 20 grams of the sample from the extract were placed in the evaporating dish. It was evaporated over steam bath until syrupy consistency is formed. 5 mL of 2M HCl was added, heated and stirred for about 5 minutes in a water bath and allowed it to cool. 0.5 grams of NaCl was added, stirred and filtered. The residue was washed with 2M HCl until the volume of the filtrate became 6mL. 1mL of the filtrate was tested with 2-3 drops of Mayer’s reagent, Wagner’s reagent and Draggendorrf’s reagent. The relative amount of precipitation was observed: (+ Slight turbidity), (++ Definite turbidity), (+++ Heavy turbidity).

3.2 Alkaloidal Analysis

The alkaline solution was extracted 3 times with 10mL of chloroform. The lower chloroform extract was combined and the upper aqueous layer for quaternary bases was reserved. The chloroform extract was evaporated to dryness in a fume hood over a steam bath. 5mL of 2M HCl was added and the solution was filtered and divided into 3 portions. 1 portion was tested with Mayer’s reagent, Wagner’s reagent and Draggendorrf’s reagent. Result was observed. Positive results indicate the presence of primary, secondary and tertiary

The residue was defatted with the use of 6mL hexane and water (2:1 v/v). It was observed by shaking the mixture; the upper hexane layer was pipetted out, then treatment was repeated with hexane until most of the colored pigments has been removed. All hexane extracts was disposed. The defatted aqueous layer was heated over a water bath to remove the residual hexane and cooled at room temperature. The solution was divided into three portions for Keller-killiani test, Liebermann-Burchard test and Salkowiski’s test. Positive result: A reddish-brown color, which may turn blue or purple, indicates the presence of