You can find informations on these links :

https://pubmed.ncbi.nlm.nih.gov/?term=Antifungal+Activity+of+Plant+Extracts

https://scholar.google.com/scholar?hl=fr&as_sdt=0%2C5&q=Preparation+and+application+of+plant+extracts+for+antifungal+activity++&btnG=

Calculate the required volume of the plant extract: You need to dilute the extract from 19 mg/mL to 10 mg/mL. This means you will need to dilute the extract by a factor of 1.9.

Calculate the volume of extract needed: To make a specific volume (let's say you want 10 mL of stock solution),

Add the solvent: To make up the final volume to 10 mL, you will need to add a solvent (usually distilled water, ethanol, or another solvent suitable for your plant extract).

@Nicolas poirier i means that which volume of solvent and volume of extract will be take for making stock solution for antifungal activity and which is the best dilution of stock solution for antifungal activity like 60% 70% 90% ?

Hi,

You may use the web tool to calculate

https://www.alfa-chemistry.com/solution-dilution-calculator.htm

https://www.alfa-chemistry.com/mass-molarity-calculator.htm

You are mixing the terms 'volume' and 'concentration", so it is impossible to answer your question.

@maria stacewicz i am talking about volume

Your units are mg/ml. These are concentration units. Volume units are mL, L.

I'm just reading the question now and I fully agree with what Maria-Stacewicz-Sapuntzakis wrote