This quest is not available in game.
Bring 7 Jungle Remedies and 1 Venom Fern Extract to Sergeant Yohwa at the Rebel Camp.
To have a chance against Kurzen, we need his healing support neutralized. He has gathered a large number of medicine men who heal his forces with jungle remedies and poison our fighters with venom fern extracts.
We need those remedies and extracts for our own. Search the Kurzen Compound - his medicine men and jungle fighters will have the remedies, and the extracts are probably stowed in some of the camp's supply boxes.