I have prepared an aqueous extract and a methanolic extract of a plant. Using the disk diffusion method, the microorganism inhibitory pattern I am intended to observe. In several literature studies, I found the Methanolic extract gives a better inhibitory zone than the aqueous one. But in my case, it is the opposite. So, it will be helpful if anyone specifying the main reason behind this and can refer to some articles (Is polar or nonpolar compounds don't matter for aqueous extract).
Thanks in advance.
In my study the ethanolic extract's inhibitory was better than the aqueous's.
Actually this is why we use both water and methanol(or ethanol) for researches like this, to compare the results and choose the best extract. But I think you should do it again with an instance antibiotic to be sure about the results
in normal cases it should be methanolic extract give better inhibitory than in case of aqueous extract but in your cases it should be repeated after establishment for all factors that may affecting your results mainly contamination.
Hi, @Karima Galal Abdel Hameed thank you for your input. Can you specifically point out the contamination types that may occurs?
After repeating your experiment and be sure, you have to analyze the both extracts using HPLC, to know the effective components, it will may be different.
Anik Banik First, I will recommend checking the reproducibility of the results accurately. Because sometimes, different results might be produced in same experiment.
Yes, there are some possible reasons behind the variations
1. Extraction efficiency of solvents could be varied which is directly related to inhibitory effects.
2. Different solvents used in the extraction process may result in the retention of different bioactive components.
3. Bioactive components of medicinal plant may differ in their solubility depending on the extractive solvents used.
4. Different bacteria have different mode of resistance. The differences in the structure of the cell envelope between gram-positive and -negative bacteria induce different effects using same solvent.
https://www.mdpi.com/2079-6382/9/2/48/htm
https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2309&context=etd
https://mmbr.asm.org/content/56/3/395.short
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Dear Prof. @Mohammed Mehadi Hassan Chowdhury
Thank you very much for describing it so easily, it really meant a lot.
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