A process for simultaneously extracting, saponifying, and isolating lutein and zeaxanthin, and a mixture of several rare carotenoids in high purity from plants without the use of harmful organic solvents. Lutein crystals containing 5% zeaxanthin were obtained from the dried petals of Marigold flowers Tagete erecla while zeaxanthin was isolated and purified from the berries of Lycium Chinese Mill (LCM berries). Similarly, this process has been employed to isolate and purify a mixture of lutein, beta-carotene, neoxanthin, violaxanthin, and lutein epoxide from green plants, preferably, kale, collard green, and spinach. These plants, to a lesser extent, also serve as a source of several rare carotenoids such as alpha-cryptoxanthin (Marigolds) and beta-cryptoxanthin (LCM berries). The purified carotenoids isolated by this process are free from impurities and serve as a safe source of nutritional supplement for human consumption as well as providing a suitable and effective color additive for human foods.