Hi Vaibhavi,

From the equation you can calculate the value of X (conc. of QE extract in ug/ml).

Now, to simplify the calculation forget about the conc. and consider the content, I mean to say the quantity. Let me explain it for you.

As you have used 1 ml of extract (conc. was 2 mg/ml) it means there was 2 mg of extract in the reaction mixture. You got X ug of QE in 1 ml that was actually in 2 mg extract. So, X ug QE/ 2 mg extract or (X÷2) ug QE/ mg extract. Suppose it is P ug QE/mg extract. Multiply both side with 1000 and you will get Q mg QE/gm of extract.

You did not mention the yield of extract from 300 gm dry powder. Now you have to do back calculation to get back to the amount of QE/ gm of dry powder.

Let me know if you need further explanation. Best wishes!

Dear Vaibhavi,

I am working with i.v. form of Q for 20 years. We study Q in patients with AMI and Acute Heart Failure. We have good result first of all for limitation of infarct size and many other aspect. Now we continue to study drug Quercetin in RCT. Could you tell me what is your interest in investigations drug with cardioprotective property? Thanks a lot! 

I am working on ACE inhibition properties of my plant extract which contain 1 of the flavonoid quercetin. but for my initial study i want to know what is total flavonoid content of plant as there are other flavonoid too..other than quercetin in my plant

thank you Sujan Bhowmick ·

from 300 gm dry powder i got 10 gm extract.

Then calculate the amount of flavoniod in 10 gm of extract which is equal to the amount of total flavonoid in 300 gm of dry powder.

Thank you..

In the linear equation obtained from the standard curve, Y is the absorbance of the sample obtained from UV-visible spectrophotometer. X is the concentration of Standard from calibration curve. From the value of X, the total Flavonoid content (mg/g) C can be calculated using following equation.

                                                   C = X x V/N

where: V=volume of extract taken in mL: N=weight of plant extract in g

In your case V = 1mL and N = 0.002 g (2mg)

and the value of X can be calculated from standard curve

First you need to use your calbiration curve. The calibration curve that you can formulate by preparing quercetin solutions at concentrations 10 to 100 μg/ml in methanol. For example the equation becomes, y =11.924x - 0.0307

Now to calculate the value of x, you need the value of y

Where y = Absorbance of your test sample (say 0.342)

x = concentration from the calibration curve

This implies that x = y + 0.0307/11.924

x = 0.0313mg/mL

Therefore, TFC can be calculated as follows

TPC = cV/m

Where c= concentration from calibration curve

V= Volume of the extract used

m= Mass of the extract used

Therefore, TPC = cV/m

TPC = 0.0313x1/0.01

TPC = 3.13mg of Q/ g of extracted compound

Regards

Ashfaq Ahmad Shah

Graphic Era University, Dehradun

Thank you all for your comments which I find helpful. This is my question, am I going to calculate the total flavonoid content for one concentration or for different concentration and then calculate the average