Nimbolide a limonoid from Azadirachta indica inhibits proliferation and induces apoptosis of human choriocarcinoma (BeWo) cells

Abstract

We investigated the cytotoxic effects of nimbolide, a limonoid present in leaves and flowers of the neem tree (Azadirachta indica) on human choriocarcinoma (BeWo) cells. Treatment with nimbolide resulted in dose- and time-dependent inhibition of growth of BeWo cells with IC(50) values of 2.01 and 1.19 microM for 7 and 24 h respectively, accompanied by downregulation of proliferating cell nuclear antigen. Examination of nuclear morphology revealed fragmentation and condensation indicating apoptosis. Increase in the generation of reactive oxygen species (ROS) that was reversed by addition of reduced glutathione suggested ROS involvement in the cytotoxicity of nimbolide. A decrease in Bcl-2/Bax ratio with increased expression of Apaf-1 and caspase-3, and cleavage of poly(ADP-ribose) polymerase provide compelling evidence that nimbolide-induced apoptosis is mediated by the mitochondrial pathway. The results of the present study suggest that nimbolide has immense potential in cancer prevention and therapy based on its antiproliferative and apoptosis inducing effects.

Nimbolide, a Limonoid Triterpene, Inhibits Growth of Human Colorectal Cancer Xenografts by Suppressing the Proinflammatory Microenvironment

“…Down-regulation of the expression of proteins involved with cell survival and proliferation may contribute to the decreased growth of colon cancer cells. The observed antiproliferative and apoptosis-inducing properties of nimbolide are in agreement with those observed by others in leukemia (24, 29), colon cancer (25, 47), neuroblastoma (20), and choriocarcinoma (31) cells. In a previous study, we demonstrated that nimbolide at lower concentrations can sensitize colon cancer cells to TRAIL by modulating apoptotic pathways (25).…”

“…This limonoid has been shown to possess numerous biological activities such as antifeedant (21), antimalarial (22), antimicrobial (23), and anticancer (19, 20, 24–30) activities. The limonoid exhibits antiproliferative activity in a wide variety of tumor cells, including neuroblastoma, osteosarcoma, choriocarcinoma (31), cervical cancer (32), leukemia, and melanoma (29) cells.…”

The neem limonoids azadirachtin and nimbolide inhibit cell proliferation and induce apoptosis in an animal model of oral oncogenesis

“…Previously, we demonstrated a decrease in Bcl-2/Bax ratio with increased expression of Apaf-1 and caspase-3, and cleavage of PARP after exposure of BeWo cells to nimbolide indicating that nimbolide mediates apoptosis by the mitochondrial pathway [17]. In the present study, we provide compelling evidence to show that azadirachtin and nimbolide transduce apoptosis by both the mitochondrial and death receptor pathways.…”

“…Nimbolide induced cell cycle arrest and antiproliferative effects in a wide range of human cancer cell lines [16,25,36]. Cells treated with nimbolide exhibited apoptotic features characterised by nuclear condensation and fragmentation, progressive vacuolization, membrane blebbing, increased appearance of annexin Vpositive cells, increase in the number of cells in the sub-G1 fraction, expression of phosphatidylserine in the outer cell membrane, generation of reactive oxygen species, and caspase-dependent apoptosis [15][16][17]. Despite its wellproven efficacy on insect cells, the cytotoxicity of azadirachtin on vertebrate cells has not been investigated except for one study that showed decreased survival of human glioblastoma cell lines treated with azadirachtin accompanied by a decrease in binucleation index, and formation of micronuclei [13].…”

“…Previously, we documented the antiproliferative and apoptosis inducing effects of nimbolide on human choriocarcinoma (BeWo) cells [17]. Recently, we demonstrated the modulatory effects of azadirachtin and nimbolide on xenobioticmetabolizing enzymes, oxidative DNA damage, invasion, and angiogenesis in the hamster buccal pouch (HBP) carcinogenesis model [18].…”