Plant is a rich source of phytochemicals. How we can identified the compounds present in plant extract without using chromatographic and spectroscopic methods?
Different chemical tests can be employed to detect presence of different classes of compounds but I think to identify compounds one have to do chromatography and/or spectroscopy
You could also use biological sensors (i.e., organisms with a visible phenotypic response to a compound). Using a bacterial biosensor generally does require some basic TLC to separate the compounds.
Qualitative Chemical Examination using various phytochemical tests is the only way out in this case. At least you will come to know what is the chemical composition of your extract. Once you know the chemical categories present in the extract, you can proceed with the isolation studies or chromatographic studies.
There are number of spot test / colour test available for qualitative analysis of phytochemicals but for quantitative estimation fractionation followed by chromatography (HPLC, GCMS) will be beneficial.
If your plant is extensively evaluated previously, then go through the literature and try to test chemically with reported method utilized for the purpose of identification of those compounds. If you are working with unknown sample, then follow the answer of Dr. Alok Nahata.
Please note that without chromatography & spectoscopic methods, identification of unknown compound is not possible. Even if it is done, it will not be authentic one.
First you can choice the polarity of the fisrt solvant used for extraction. If you want to extrract hydrophilic compounds, use a mixture of methanol-water, then you can use less polar solvant (e.g. methanol only or methanol-éthyl acetate) to extract compounds from the residue of the first extraction, and so on. At each steps use more lipophylic solvant until hexane or petroleum ether. Each soluble fraction contains a class of compounds : from sugar, amino acids etc.. to lipids. In each fraction you can try to separate the different compounds by TLC or try to identify the class of compounds by chemical reactions, but it is impossible to identify the chemical structure of compounds without more sophisticated analytical methods such as HPLC, GC, MS and NMR. I suggest to you to prepurify the plant extract as described previously and look for a colaboration with an organic chemistry or phytochemistry department to identify the different components of each fraction. It is always possible to propose a common project to establish a constructive collaboration with other scientists. Don't hesitate to contact phytochemists in other countries, they may be interested to identify compounds from plants of your country.
Phytochemical screening method can be used. This involves adopting chemical reactions to identify the various functional groups present. Different solvent extracts can be tested for by the addition of precipitating or colour inducing reagents. Different functional groups present in the extracts react with these reagents to produce specific characteristic precipitates or colors that can be used to identify them. However, as said by Roger Pezet, these processes do not lead to the drawing of the chemical structure but they are good indicators.
The input of Roger Petez is quite comprehensive. Isolation is not an easy task if you do not have an organic chemistry background or collaborator. The steps for separation and isolation as described above requires a lot of expertize as well as having the relevant chemicals and equipment. There are many modern spectroscopic techniques which makes separation and isolation easy e.g Hplc coupled to MS, Hplc-QTOF, LC-MS etc. Wish you good luck.
Some of the preliminary methods which will help to identify name of phyto-compounds without chromatographic techniques. Phytochemical method of Harborne and Johanson microchemical techniques 1940 and Trease and Evans for phytochemical identification .
I am little confused. What is wrong with these standard methods widely used by researchers all over the world? I do not think it is wise to go back to tedious, time consuming chemical reactions or titrimetric methods. Collaboration is a good idea if funds and facilities are the issues.
I am agree Dr.Rajeswara. May be Vinesh don't have any possibility to use chromatographic and spectroscopic methods in his university, is it right Vinesh?. Tell us why you want to go back to earliest methods?.
I appreciate your concern for the environment . From the answers you have given to the questions of other researchers on ResearchGate, I understand that you are quite knowledgeable about the isolation and identification procedures and techniques in vogue for natural products or phytochemicals from plants and yet you solicit responses from other researchers. This showcases your quest for new knowledge and techniques, which is praiseworthy. Though I have not worked, my colleagues from other institutes are trying ionic liquids which are claimed as environmentally safe green solvents. I think you are aware of them. May be you can check recent literature and try some of them. The concept of "green chemistry" is also one of the topics often discussed among scientific circles. I am sure you are aware of this too.
This whole discussion brings forth one important thing, how to frame a question to solicit appropriate responses form expert scientists. Your question and the explanatory notes missed out on the environmental view point, hence the confusion. I wish you do not disagree with me.
Thanks for your kind appreciation. Yes, I know Green Chemistry can be applicable in environmental point of view for extraction and isolation. With this I am also trying to develop new alternatives which will be easy for the phytochemical studies. Your knowledgeable and valuable support will be vital.
After isolation, first recrystallized then perform following test like melting point, functional group, saturated or unsaturated ,aromatic etc after test you may assumes related compounds. but finally you can not confirm without sophisticated installment analysis.