Limonin is a chemically-induced carcinogenesis inhibitor and HIV-1 replication inhibitor.The human immunodeficiency virus (HIV) is a lentivirus that causes the acquired immunodeficiency syndrome (AIDS).

When culturing the HIV-1 in human peripheral blood mononuclear cells (PBMC) and monocytes/macrophages (M/M), Limonin inhibit the HIV-1 replication in all cellular systems and inhibit HIV-1 replication with EC50 value of 60u μM in PBMC cells in a dose-dependent way [1]. In human hepatoma HepG2 cells, limonin can induced apoptosis, which was evidenced by WB analysis of some apoptosis factors [2].

In the female Syrian hamsters treated with DMBA, which can cause tumor, limonin showed a 60% reduction in tumor burden. It decreased 20% tumor number and 50% tumor mass [3]. In male F344 rats treated with azoxymethane (AOM), 0.05% limonin in diet significantly reduced (65%-92% inhibition) the incidence of colonic adenocarcinoma. Thus, limonin has chemopreventive effects on chemically induced carcinogenesis [4].