Why Plants Have Strong Flavors and Effects

Animals can also use their mobility to avoid becoming another creature’s meal, by fleeing or fighting. But stationary plants? They compensate for their immobility with a remarkable ability for chemical synthesis. These master alchemists produce thousands of strong-tasting, sometimes poisonous warning signals that discourage bacteria, fungi, insects, and us from attacking them. A partial list of their chemical warfare agents would include irritating compounds like mustard oil, hot-chilli capsaicin, and the tear-inducing factor in onions; bitter and toxic alkaloids like caffeine in coffee and solanine in potatoes; the cyanide compounds found in lima beans and many fruit seeds; and substances that interfere with the digestive process, including astringent tannins and inhibitors of digestive enzymes.