Limonoids from Citrus: Chemistry, anti-tumor potential, and other bioactivities

Citrus limonoids are tetranortriterpenoids compounds mainly found in oranges, lemons, grapefruits, and other fruits of Citrus. They are proved to be the leading cause of bitterness in Citrus fruits and are mainly consumed for therapeutic purposes and as food. Numerous studies have focused on Citrus limonoids and intend to develop new chemotherapeutic or complementary medicine in recent years. Citrus limonoids showed various bioactivities such as anti-tumor, antioxidative, anti-inflammatory, anti-neurological diseases, immunomodulatory, anti-insect, anti-bacteria, antiviral activities, etc. This review summarized limonoids from Citrus to date, along with their chemical structures and biological activities with a particular focus on their anti-tumor potential.