Is there any reason for using the above mentioned solvents for antibacterial screening in single medicinal plants?
methanol is more used than ethanol, the boiling point of Ethanol is 78.4 °C while the boiling point of methanol is 64.7 °C. so when you have a methanol extract you need lower temperature to evaporate the solvent in the rotaryvapor so the extract is less damaged than the ethanol one.
I have not worked with plants, but rather with insect venoms, and I guess it is essentially because it is practical. Many secondary metabolites of plants are soluble in these solvents (which on their part also are not too toxic nor too volatile for the manipulator) and can be partially purified quickly by classical chromatography methods. Do you want to use other solvents?
Hi,
most of the polar compounds are easily eluted by these solvents which is bioactive responsible for their activity.
some non polar groups may also be dissolved in these solvents.
easy to evoparate the elutant
for quick & easy availability.
methanol is more used than ethanol, the boiling point of Ethanol is 78.4 °C while the boiling point of methanol is 64.7 °C. so when you have a methanol extract you need lower temperature to evaporate the solvent in the rotaryvapor so the extract is less damaged than the ethanol one.
Hi
I agree with Eduardo Fox and Noorjahan A that most of the bioactive compounds are soluble n these type of solvents and it also helps us to purify the compounds for further analysis. But ethanol and methanol are not always used to solubilized these compounds other polar non polar and mid polar compounds are also used that depends on the type of compounds which you want to extract and also about its solubility in the solvents.
I hope this will help you out
Actually most of the polar groups like phenolics, alkaloids, terpenes with glycoside they are showing good antibacterial activity which are generally dissolve in methanol and ethanol but then even some of the phytochemicals like glycoside are so much polar so that they are sparingly soluble in these solvent so to compare with you can use water extract also.
This due to the extent ability of ethyl and methyl alcohols to solublize most of secondary metabolites.
But you have to make sure that you evaporated all the alcohol amounts to avoid any possible false positive activities as antimicrobial due to any alcoholic remains
These solvents are very suitable for the extraction of polar and some non- polar metabolites. The basic difference is their boiling points and the nature of work .If it involves animal experiment, ethanol is preferred because it is less toxic to human and animal cells. Methanol is more toxic and any residual quantity in the extract may give false positive results.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.452.9330&rep=rep1&type=pdf
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