An extensive review of uses of the moringa tree, written by Dr. Julia Morton, appears in the current issue of Economic Botany. I thought I should bring one paragraph to your attention.
"The root, best known in India and the Far East, is extremely pungent. When the plant is only 60 cm tall, it can be pulled up, its root scraped, ground up and vinegar and salt added to make a popular condiment much like true horseradish. ...The root bark must be completely removed since it contains two alkaloids allied to ephedrine -- benzylamine (moringine), which is not physiologically active, and the toxic moringinine which acts on the sympathetic nerve endings as well as on the cardiac and smooth muscles all over the body. Also present is the potent antibiotic and fungicide, pterygospermin. The alkaloid, spirachin (a nerve paralyzant) has been found in the roots.... Even when free of bark, the condiment, in excess, may be harmful."
The key words are "in excess." I worked one summer in the laboratory of forage scientist Dr. VanSoest at Cornell University. He said we should learn a lesson from the deer. Deer can eat plants with no ill effect that are poisonous to cattle. The difference is that deer are browsers. They eat a small amount of one thing, then move on to many other things during the course of the day. In contrast, when a cow likes something it keeps eating. "The body is capable of detoxifying small amounts of a great many things."
I have thought of that many times since working with so many kinds of plants at ECHO. No doubt a steady diet of some would be harmful, as is the case with many common foods like cassava which contains cyanide or spinach with oxalates. There is a comforting degree of safety in "browsing" among a large selection of foods. Not only will your body more likely be able to detoxify the small amounts of any particular toxin, but it is more likely to find at least a minimal amount of the various nutrients it requires. All the more reason to work to bring diversity to the diets of people with whom we work.
ECHO Staff 1991. Caution about using Moringa Tree Roots as a Horseradish Substitute. ECHO Development Notes no. 35