Flavinoid test

Respected Sir,
Please try with the following method by Eom et al., 2007.
Eom, S.H., Cheng, W.J., Hyoung, J.P. Kim, E.H., Chung, M.I., Kim, M.J., Yu, C.Y. and Cho, D.H. 2007. Far infrared ray irradiation stimulates antioxidant activity in Vitis flexuosa Thunb. Berries. Kor. J. Med. Crop Sci. 15: 319.323.

Estimation of Flavonoids
The total flavonoids content was determined according to Eom et al. (2007). An aliquot of 0.5 ml of sample (1 mg/ml) was mixed with 0.1 ml of 10% aluminium chloride and 0.1 ml of potassium acetate (1 M). In this mixture, 4.3 ml of 80% methanol was added to make 5 ml volume. This mixture was vortexed and the absorbance was measured spectrophotometrically at 415 nm.

Good Luck

Three methods were used to detect the presence of flavonoids in the plant sample. Five ml of dilute ammonia solution were added to a portion of the aqueous filtrate of each plant extract followed by addition of concentrated H2SO4. A yellow coloration observed in each extract indicated the presence of flavonoids. The yellow coloration disappeared on standing. Few drops of 1% aluminium solution were added to a portion of each filtrate. A yellow coloration was observed indicating the presence of flavonoids.
A portion of the powdered plant sample was in each case heated with 10 ml of ethyl acetate over a steam bath for 3 min. The mixture was filtered and 4 ml of the filtrate was shaken with 1 ml of dilute ammonia solution. A yellow coloration was observed indicating a positive test for flavonoids.



Dear Nagendra

You can try following tests for qualitative detection of phenolics and flavonoids:

A. Ferric chloride Test: The extract is dissolved in distilled water. To this, few drops of neutral 5% ferric chloride solution are added. A dark green colour indicates the presence of phenolic compounds.

Ferric chloride test solution: a 5% w/v solution of ferric chloride in water.

B. Gelatin Test: The extract is dissolved in distilled water and 2 ml of 1% solution of gelatin containing 10% sodium chloride is added to it. White precipitate indicates the presence of phenolic compounds.

C. Lead Acetate Test: The extract is dissolved in distilled water and 3 ml of 10% lead acetate solution is added. A bulky white precipitate indicates the presence of phenolic compounds.

D. Alkaline Reagent Test: An aqueous solution of the extract is treated with 10% ammonium hydroxide solution Yellow fluorescence indicates the presence of flavonoids.

E. Zn/HCl or Mg/HCl Reduction: The extract is dissolved in alcohol and few fragments of magnesium ribbon and concentrated hydrochloric acid (drop wise) are added. If any pink to crimson colour develops, presence of flavanol glycosides is inferred by the development of pink to crimson colour.

Best  Wishes