@ Chirouf Sehla ,

The use of different solvents such as water, ethanol, methanol, ethyl acetate, acetone, hexane, petroleum ether etc, is practiced so as to get the maximum phytochemicals extracted. No doubt that water is a universal solvent but extraction of phytochemicals also depends upon the polarity of the solvent as well. Thus different solvents are used.

Soxhlet extraction method is quite useful for the preparation of extracts.

Sometimes a single phytochemical may be studies using different methods. So the efficacy of the method depends upon the phytochemical to be screened.

Here i would like answer your question in 3 parts

1. The extraction using solvents - The extract will use different solvents to separate the material according to the polar and non polar solvents using water ethanol methanol , ethyl acetate etc.

2. Methods - using different method like Soxhlet extraction , column chromatography

3. Quantification and quality - Using HPLC and LCMS methods

Regards

Before going to Extraction you should take Confirmatory Test (CT), Which types of Secondary metabolites present in your material. Then choose the polar and non-polar solvents using water-ethanol methanol, ethyl acetate, etc. Quantification and quality - Using HPLC and LCMS methods

Phytochemical screening and pharmacognostical studies are the steps involved in the standardisation of crude drugs. It also report the major active secondary metabolites present in the selected solvents ie non polar to polar.