You don't need MAOI's to make cactus active. And you don't have to do an extraction either.
If you mix MAOI's with psychoactive cactus it will potentiate the effects, and certain people can have adverse effects because the stimulant effects of this combo. If doing this you would most likely be fine, just use caution, I gave myself a minor heat-stroke one time because I was being a little reckless with this combo (I was working in the hot sun and not staying well enough hydrated)
Extracts reduce the amount of material you have to consume, and some find this more pleasant.
My personal favorite method of ingestion is to just stuff the powder into capsules and eat them. You can also make a tea out of the powder, but this requires some technique to get it right and it can be quite foul tasting.
“Surrender is inner acceptance of what is without any reservations. If you have lived long enough, you will know that things “go wrong” quite often. It is precisely at those times that surrender needs to be practiced if you want to eliminate pain and sorrow from your life.”
Eckhart Tolle