Once you decide which part of the plant you will be using for extraction, you can search for the method. For different constituents, different methods are available.

Are these known compounds? If so, a literature search on the plant and compounds is a good place to start. LC-MS would work well.

If they are unknown compounds, do a literature search on your plant and see what has already been discovered.

You are looking at several classes of compounds and no single method will work for all of them.

Taking into consideration that there are several classes of compunds which you're looking for, a single method/test for analyzing all af them does not exist. In a first step you should try some preliminary qualitative tests for each of these groups of metabolites (Shinoda for flavonoids, Draggendorf for alkaloids, etc.) and then look for more modern and specific tests. For example, the UV spectra can give you very useful information, specially in the case of flavonoids, where you gat spectra in Methanol and add different substances (sodium acetate, sodium methoxide, aluminum choride, hydrochloric acid) to get information of the substitution pattern in the flavonid nucleus.

You need to carryout some preliminary (qualitative) tests using different solvents and then proceed to quantifying them. Various methods are available, so we would like to know what exactly you want. This could be helpful.

Test for Alkaloid

The extract (1.0ml) was shaken with 5.0ml of 2% HCL on a steam bath and filtered. To 1ml of the filtrate, Wagner’s reagent (iodine in potassium iodide solution) was added. A reddish brown precipitate confirms that its presence.

Test for Saponin

One millilitre of the filtrate was diluted in 1ml of water and shaken vigorously. A strong frothing confirms presence of saponin.

Test for Tannins

Five millilitres of the extract was added to 2.0ml of 1% HCL. Deposition of a red precipitate shows the presence of tannin.

Test for Hydrogen Cyanide

This was done using spot paper test. One millilitre of the extract was added with 2-3 drops of toluene solution. A change from the yellow colour of the paper to brick red colour is a positive result for hydrogen cyanide.

Test for Steroid

The extract (1ml) was dissolved in 2.0ml of chloroform in a test-tube, and then 1ml of conc. H2So4 was added. Formation of reddish brown colour at the inter-phase confirms the presence of steroid.

Test for Phenol

The extract (1.0ml) was added with 1.0ml of 10% ferric chloride. The formation of a greenish brown or black precipitate or colour is taken as positive for a phenolic nucleus.

Test for Flavonoid

The extract (1.0ml) was diluted in 1.0ml of diluted NaoH. Formation of precipitate shows the presence of flavonoid.

Dear RG colleague

Simply, you can began using TLC with some standards.

HPLC is a good and useful method for identifying phytochemicals. If you work on essential oils, GC-MS.

Best regards

thanks for all research gate colleagues for useful information.