cells, the limonin was found to help fight cancers of the mouth, skin, lung, breast, stomach, and colon. California-based Dr Gary Manners said: "Limonin is present in citrus and citrus juices in about the same amount as vitamin C." For the latest experiment, 16 volunteers were given a drink made from limonin in quantities equivalent to drinking seven glasses of orange juice. The researchers also found the limonin stayed in the body far longer than they had expected.