Limonoids from the genus Trichilia and biological activities: review

Limonoids, present in the families Meliaceae and Rutaceae, provide the bitter principles in citrus and are derived from limonin (first isolated tetranortriterpenoid). These compounds are highly oxygenated triterpenoids that have lost the four carbon atoms of the side chain and they have attracted attention because they demonstrate several pharmacological activities. Especially in Meliaceae, the Trichilia genus, one of the largest, with 81 species, has long interested scientists due to its limonoids with different biological activities, such as insecticidal, anti-inflammatory, and antineoplastic, among other activities. Based on this, an evaluation was performed of all naturally occurring limonoids from the Trichilia genus, as well as their various bioactivities. In total, 227 limonoids were identified in 21 species distributed in the American, African, and Asian continents. These were separated into three major groups: intact rings, ring-seco, and rearranged limonoids. The compounds with the intact and seco rings are present in greater quantity in the native species of America and Africa, since the rearranged limonoids are concentrated in the Asian species. Finally, a discussion was provided of their biological activities and biosynthesis.