You need to isolate compounds firstly, I am sending you as an attachment the paper you should follow in my opinion. The new compounds, as you probably know have mass spectra which are not available in databases, and in the published material worldwide and their 1D and 2D spectra must be recorded and solved in order to be sure that you have new compound. You must record also their UV and IR spectra as well.

Hopefully, this will help. I wish you good luck in your work.

If you want to determine antioxidant activity of compounds, please see my profile and publication in Bulletin of the ethiopian chemical society.

thank you, I need to determine the antioxidant of the extract before identification

There are so many methods related to examination of antioxidant potential of plant extracts. I think you can try DPPH Scavenging method as it does not depend upon the polarity of the extract. You may refer the attached papers based on DPPH assay.

thank you for the valuable data,

what is the best solvent to dissolve the plant extract for the DPPH method

People have used Methanol so you should try the same. Refer the attachments they are having some really good information about DPPH assay.

thank you

You can have all information about determination of antioxidant activity as I mentioned in publication available in my profile (Bulletin of the Ethiopian chemical society) published in 2013....

The most availalble and easiest procedure for antioxidant activity of crude plant extract before its identification is DPPH free radical scavenging assay using Trolox as standard reference

Biologically, antioxidants play their health-beneficial roles via transferring a hydrogen (H) atom or an electron (e–) to reactive species, thereby deactivating them. Antioxidant activity assays imitate this action; that is, antioxidants are measured by their H atom transfer (HAT) or e– transfer (ET) to probe molecules. Antioxidant activity/capacity can be monitored by a wide variety of assays with different mechanisms, including HAT, ET, and mixed-mode (ET/HAT) assays, generally without distinct boundaries between them.

thank you