Disclosed are methods for obtaining a natural product preparation with reduced glucosinolate contamination from a plant of Brassicaceae. The methods can include cultivating a plant callus from a plant capable of producing a desired natural product, selecting a callus with reduced glucosinolate production, and cultivating the selected callus in a liquid medium. The method can also include recovering the natural product from the culture. Also disclosed are methods for obtaining cabbage anthocyanin with reduced glucosinolate contamination. The methods can include cultivating a red cabbage plant callus with reduced glucosinolate production in a liquid medium to obtain a suspension culture and cultivating the suspension culture in a medium lacking a nitrogen source. The method can also include recovering the anthocyanin with reduced glucosinolate contamination from the culture. Finally, several specific low-glucosinolate cell lines are described.