Peeling Away Problems

The Antioxidating, Antimicrobial, and Antimutagenic Effects of Tree Bark

Folin-Ciocalteau Assay

(See Reference 5 for more details)

Using gallic acid (3, 4, 5-trihydroxybenzoic acid or C₆H₂(OH)₃CO₂H ) as a standard:

1.      Make a 5mg/ml gallic acid stock solution by weighing 5 mg of gallic acid, adding 100µL Ethanol to resolve, then adding 900µL of water. 

2.      Add 0, 10, 20, 30, 50, and 100 µL of gallic acid stock solution to a tube and then add 1000, 990, 980, 970, 950, and 900 µL of water respectively (so that the total solution is 1000µL) to make 0, 0.05, 0.1, 0.15, 0.25, and 0.5 mg/ml gallic acid working solution. 

3.      Add 10µL of each gallic acid working solution and 1µL of each tree bark sample (since the bark extracts are more concentrated) into separate tubes. 

4.      Add 790µL of H₂O for each gallic acid sample and 799µL of H₂O for each tree bark sample into the tubes. 

5.      Add 50µL of Folin-Ciocalteau Reagent. 

6.      Mix well, then wait between 30 seconds and 8 minutes. 

7.      Add 150µL of sodium carbonate solution (Na₂CO₃), mix well.

8.      Leave the solution at 40ºC for 30 minutes. 

9.      Pipette each reaction into separate cuvette and put into a spectrophotometer. 

10.  Read the absorbance of each of the samples at A₇₆₅ (Absorbance at 765 nm wavelength) against 0 mg/ml of gallic acid reaction.

Sodium Carbonate Solution  

       800 mL       water (H₂O)

       200 g       anhydrous sodium carbonate (Na₂CO₃)

       bring to a boil 

       after cooling, add a few crystals of sodium carbonate (Na₂CO₃)

       filter and add water to 1L

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