Diverse limonoids from barks of Toona ciliata var. yunnanensis and their biological activities

Toona ciliata Roem., belonging to the Meliaceae family, is now much cultivated throughout the tropics for its colour wood hearts suitable for architecture and furniture. Large amount of barks of T. ciliata are available as the by-product of wood first-stage processing, which also have been used as a Chinese folk medicine to treat diarrhea, dysentery, and ringworm. In order to further exploit their potential uses, 22 new limonoids, ciliatasecones D–Y (1–22) and eight known ones (23–30) were isolated from the barks of this plant in our current research. The cytotoxicity, anti-inflammatory, and anti-multidrug resistance (MDR) activities of these isolates were also evaluated. Compounds 3, 8, 27, and 29 at the concentration of 50 μM displayed significant MDR reversal activities in MCF-7/DOX cells to conventional anticancer drug doxorubicin. Compounds 3 and 29 exerted potentiation effects of 107.94 and 351.50-fold better than the positive control verapamil. This study added new data to the investigations of the structural diversity and biological activity of limonoids and provided phytochemical and pharmacological evidences for the further industrial and medicinal utilization of the barks of this common plant resource.